Biology subjects

Johnson, C. C.

Publications and source records attributed to Johnson, C. C..

7 recordsLinked to original sources

bioRxiv2025

Immune pathways and perinatal environmental exposures contribute to epigenetic gestational age prediction and acceleration

DNA methylation (DNAm), capturing biological gestational age (GA) and epigenetic gestational age acceleration (EGAA), can be modified by environmental exposures. The Asthma&Allergy array is a new DNAm array developed with content focused on asthma and allergy loci. The association between content on the Asthma&Allergy array and chronological GA and EGAA has not been evaluated alone or in the context of perinatal exposures. We performed an epigenome wide association study(EWAS) based on chronological GA at single CpG sites and regions. We further constructed a multi-CpG site methylation model to predict chronological GA in cord blood from 391 newborn children from a Detroit-based birth cohort. Associations between perinatal environmental factors with GA, epigenetic gestational age (EGA), and EGAA were assessed. We identified 2,435 CpG sites associated with chronological GA. HLA class II (HLA-DRB1,HLA-DQB1,HLA-DRB6) were the most significantly associated with chronological GA. Our multi-CpG site model attained predictive accuracy (cross-validated Pearsons correlation=0.75) comparable to other EGA methods. Using genes implicated in region-based analyses (n=395 regions), the pathways most significantly enriched with chronological GA-associated CpGs included T helper 1(Th1) and 2(Th2) activation, macrophage classical activation, and IL10 signaling, which were also enriched in at least one of the other published epigenetic clocks. In multi-exposure models, prenatal indoor pet exposure and unplanned C-section were associated with EGA deceleration, while infants first-born status was associated with EGAA. Our findings highlight enrichment for T cell modulated pathways and antigen presentation as biological processes enriched in chronological GA, as well as novel perinatal factors that may impact EGAA.

genomics↗

bioRxiv2025

A targeted LC MS/MS assay of a health surveillance panel and its application to chronic kidney disease

Robust and reproducible assays capable of specific and quantitative monitoring of multiple biologically important proteins amongst the thousands of human plasma proteins can potentially be used to distinguish health versus disease. In this study, we established an LC-MS assay to monitor a Health Surveillance Panel (HSP) comprising 60 circulating plasma proteins selected based on their broad biological functions and assay performance. Plasma samples were prepared for proteomic analysis in an automated process. A scheduled LC-MRM assay with a 30-minute 5% - 35% acetonitrile gradient and 50.5 minutes of total run time was used to quantify the 60 endogenous proteins by monitoring 364 transitions from 117 proteotypic peptides along with their stable isotopic labeled standard peptides in a single assay. For each proteotypic peptide, we selected a quantifier ion and at least two qualifier ions. The quantifier ions have a linear response over a 100-fold range, and the peak area ratios of the three peptide ions were consistent. As proof of concept, we evaluated the performance of our HSP assay in a case-control study of progressive chronic kidney disease (CKD). Reduced plasma concentrations of alpha-2-antiplasmin, antithrombin-III, and immunoglobulin heavy constant alpha 1 correlated with CKD indicated by reduced GFR with p values < 0.05. These results demonstrate that the HSP proteins can be accurately and reproducibly quantified with a high-quality multiplexed MRM assay and the HSP assay can detect disease-associated differences.

biochemistry↗

bioRxiv2023

FluoMALDI microscopy: matrix co-crystallization simultaneously enhances fluorescence and MALDI imaging

We report that co-crystallization of fluorophores with matrix-assisted laser desorption/ionization (MALDI) imaging matrices significantly enhances fluorophore brightness up to 79-fold, enabling the amplification of innate tissue autofluorescence. This discovery facilitates FluoMALDI, the imaging of the same biological sample by both fluorescence microscopy and MALDI imaging. Our approach combines the high spatial resolution and specific labeling capabilities of fluorescence microscopy with the inherently multiplexed, versatile imaging capabilities of MALDI imaging. This new paradigm eliminates the notion that MALDI matrices obscure and obstruct optical microscopy approaches, allowing to image the exact same cells in tissues, free of any physical changes between fluorescence and MALDI imaging, which minimizes data registration processes. Matrix-fluorophore co-crystallization also facilitates applications with insufficient fluorescence brightness. We showcase the capabilities of FluoMALDI imaging with endogenous and exogenous fluorophores and autofluorescence-based FluoMALDI of brain and kidney tissue sections. FluoMALDI will advance structural-functional microscopic imaging in cell biology, biomedicine, and pathology.

biochemistry↗

bioRxiv2023

RaMALDI: enabling simultaneous Raman and MALDI imaging of the same tissue section

Multimodal tissue imaging techniques that integrate two complementary modalities are powerful discovery tools for unraveling biological processes and identifying biomarkers of disease. Combining Raman spectroscopic imaging (RSI) and matrix-assisted laser-desorption/ionization (MALDI) mass spectrometry imaging (MSI) to obtain fused images with the advantages of both modalities has the potential of providing spatially resolved, sensitive, and specific biomolecular information, but has so far involved two separate, consecutive tissue sections for RSI and MALDI MSI, resulting in images from two separate entities with inherent disparities. We have developed RaMALDI, a streamlined, integrated, multimodal imaging workflow of RSI and MALDI MSI, performed on a single tissue section with one sample preparation protocol. We show that RaMALDI imaging of various tissues effectively integrates molecular information acquired from both RSI and MALDI MSI of the same sample. Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/539107v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1829ccaorg.highwire.dtl.DTLVardef@3d018org.highwire.dtl.DTLVardef@531015org.highwire.dtl.DTLVardef@144f1a3_HPS_FORMAT_FIGEXP M_FIG C_FIG We demonstrate for the first time RaMALDI imaging, a streamlined, integrated multimodal imaging workflow of Raman spectroscopy imaging (RSI) and matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI), which is performed on a single sample and uses one sample preparation protocol. RaMALDI imaging of various tissues effectively integrates molecular information acquired from both RSI and MALDI MSI of the same sample.

bioengineering↗

bioRxiv2021

Capturing the start point of the virus-cell interaction with high-speed 3D single-virus tracking

The early stages of the virus-cell interaction have long evaded observation by existing microscopy methods due to the rapid diffusion of virions in the extracellular space and the large 3D cellular structures involved. Here we present an active-feedback single-particle tracking method with simultaneous volumetric imaging of the live cell environment to address this knowledge gap to present unprecedented detail to the extracellular phase of the infectious cycle. We report previously unobserved phenomena in the early stages of the virus-cell interaction, including skimming contact events at the millisecond timescale, orders of magnitude change in diffusion coefficient upon binding, and cylindrical and linear diffusion modes along cellular protrusions. Finally, we demonstrate how this new method can move single-particle tracking from simple monolayer culture towards more tissue-like conditions by tracking single virions in tightly packed epithelial cells. This multi-resolution method presents new opportunities for capturing fast, 3D processes in biological systems. One-Sentence SummaryActive-feedback 3D single-particle tracking enables an unprecedented look at the early stages of virus-cell interactions.

biophysics↗

bioRxiv2019

TLR5 participates in the TLR4 receptor complex and biases towards MyD88-dependent signaling in environmental lung injury

Lung disease causes significant morbidity and mortality, and is exacerbated by environmental injury, e.g. through lipopolysaccharide (LPS) or ozone (O3). Toll-like receptors (TLRs) orchestrate immune responses to injury by recognizing pathogen- or danger-associated molecular patterns. TLR4, the prototypic receptor for LPS, also mediates inflammation after O3, triggered by endogenous hyaluronan. Regulation of TLR4 signaling is incompletely understood. TLR5, the flagellin receptor, is expressed in alveolar macrophages, and regulates immune responses to environmental injury. Using in vivo animal models of TLR4-mediated inflammations (LPS, O3, hyaluronan), we show that TLR5 impacts the in vivo response to LPS, hyaluronan and O3. We demonstrate that immune cells of human carriers of a dominant negative TLR5 allele have decreased inflammatory response to O3 exposure ex vivo and LPS exposure in vitro. Using primary murine macrophages, we find that TLR5 physically associates with TLR4 and biases TLR4 signaling towards the MyD88 pathway. Our results suggest an updated paradigm for TLR4/TLR5 signaling.

immunology↗

bioRxiv2018

Neonatal gut-microbiome-derived 12,13 DiHOME impedes tolerance and promotes childhood atopy and asthma

Neonates at risk of childhood atopy and asthma are characterized by gut microbiome perturbation and fecal enrichment of 12,13 DiHOME(1); however, the underlying mechanism and source of this metabolite remain poorly understood. Here we show that 12,13 DiHOME treatment of human dendritic cells altered peroxisome proliferator-activated receptor {gamma} regulated gene expression and decreased immune tolerance. In mice, 12,13 DiHOME treatment prior to airway challenge exacerbated pulmonary inflammation and decreased lung regulatory T cells. Neonatal fecal metagenomic sequencing revealed putative bacterial sources of 12,13 DiHOME. In our cohort, three bacterial genes and their product, 12,13 DiHOME, are associated with increased odds of childhood atopy or asthma, suggesting that early-life gut-microbiome risk factors may shape immune tolerance and identify high-risk neonates years in advance of clinical symptoms.\n\nOne Sentence SummaryEarly-life gut-microbiome risk factors may shape immune tolerance and identify neonates at high-risk of disease.

microbiology↗