Kelsey E. Johnson, PhD
Postdoctoral Fellow, Department of Genetics, Cell Biology & Development
Contact information
University of Minnesota
Biography
I attended University of Wisconsin - Madison for my undergraduate degree in Zoology, and the University of Pennsylvania for my PhD where I studied human population and statistical genetics. Towards the end of my PhD I had my first child and as I spent a lot of time reading about human milk in the office lactation room, I became interested in the role of genetics in human milk composition. This struck me as a very understudied area, and I thought that a better understanding of the effects of genetic variation on milk composition could allow us to disentangle the effects of variation in milk composition on infant health. I decided to pursue this interest for my postdoc and came to the University of Minnesota, where I found an amazing team of advisors to guide me on this project. In addition to working with Dr. Demerath, I am advised by Ran Blekhman and Frank Albert in the Department of Genetics, Cell Biology and Development in the College of Biological Sciences.
Published articles
Kelsey E. Johnson – PubMed Articles
Gestational diabetes, human milk oligosaccharide concentrations, and their links to infant weight gain and the gut microbiome in a United States observational cohort
CONCLUSIONS: Mothers with a GDM diagnosis had higher milk concentrations of LNFP III and 6'SL, and 6'SL was in turn associated with increased infant growth rate, but neither HMO was associated with differential infant gut microbial abundances. The results suggest that the link between 6'SL and faster infant growth, if causal, occurs via mechanisms independent of the infant gut microbiome. This study was registered at clinicaltrials.gov as NCT03301753.
Assembly of the infant gut microbiome and resistome are linked to bacterial strains in mother's milk
The establishment of the gut microbiome in early life is critical for healthy infant development. Although human milk is recommended as sole nutrition for the infant, little is known about how variation in the milk microbiome shapes the microbial communities in the infant gut. Here, we quantified the similarity between the maternal milk and the infant gut microbiomes using 507 metagenomic samples collected from 195 mother-infant pairs at one, three, and six months postpartum. Microbial taxonomic...
Genomics of host-microbiome interactions in humans
The human microbiome is a complex ecosystem of microorganisms that inhabit the human body and have a crucial role in human health. Microbiome composition is shaped by its interaction with many factors, including human genetics. Advances in genomic technologies are improving the ability to quantify the effect of human genetics on the microbiome through improved heritability studies and microbiome genome-wide association studies (GWAS). Complementary studies using transcriptomic analyses are...
Maternal Physical Activity and Its Relationship to the Human Milk Metabolome and Infant Body Composition
CONCLUSION: Maternal exercise was associated with differences in the breast milk metabolome. Metabolites that were associated both with acute exercise and habitual activity correlated with infant adiposity measures.
Patient-reported outcomes for remote and in-person visits for genetic counseling in adult neurology
At our center, we offer clinical genetic counseling (GC) visits for adults with a personal and/or family history of neurologic disease. Here, we report patient experience and outcomes from different visit modalities (e.g., in person, videoconferencing, and telephone) in clinical neurogenetics. Individuals who completed a GC visit in the Neurology Department at the University of Pennsylvania between January 2021 and January 2023 were surveyed after an initial evaluation and/or a disclosure visit....
Receptor-Interacting Protein Kinase-3 Expression Impacts Ocular Vascular Development and Pathological Neovascularization
Functional cell death pathways are essential for normal ocular vascular development and tissue homeostasis. As our understanding of necrosis-based cell death pathways has expanded, the inclusion of regulated forms, including necroptosis, ferroptosis, and oxytosis, has occurred. Although the existence of these pathways is well described, our understanding of their role during vascular development and pathological neovascularization is very limited. Here, we examined the role of...
Gestational Diabetes, the Human Milk Metabolome, and Infant Growth and Adiposity
CONCLUSIONS AND RELEVANCE: In this observational cohort study, GD was associated with altered concentrations of several human milk metabolites. The associations between these metabolites and infant growth suggest that milk compositional differences in mothers with GD may beneficially moderate the growth and body composition of their infants.
Lethal COVID-19 associates with RAAS-induced inflammation for multiple organ damage including mediastinal lymph nodes
Lethal COVID-19 outcomes are attributed to classic cytokine storm. We revisit this using RNA sequencing of nasopharyngeal and 40 autopsy samples from patients dying of SARS-CoV-2. Subsets of the 100 top-upregulated genes in nasal swabs are upregulated in the heart, lung, kidney, and liver, but not mediastinal lymph nodes. Twenty-two of these are "noncanonical" immune genes, which we link to components of the renin-angiotensin-activation-system that manifest as increased fibrin deposition, leaky...
Human milk variation is shaped by maternal genetics and impacts the infant gut microbiome
Human milk is a complex mix of nutritional and bioactive components that provide complete nourishment for the infant. However, we lack a systematic knowledge of the factors shaping milk composition and how milk variation influences infant health. Here, we characterize relationships between maternal genetics, milk gene expression, milk composition, and the infant fecal microbiome in up to 310 exclusively breastfeeding mother-infant pairs. We identified 482 genetic loci associated with milk gene...
Human cytomegalovirus in breast milk is associated with milk composition and the infant gut microbiome and growth
Human cytomegalovirus (CMV) is a highly prevalent herpesvirus that is often transmitted to the neonate via breast milk. Postnatal CMV transmission can have negative health consequences for preterm and immunocompromised infants, but any effects on healthy term infants are thought to be benign. Furthermore, the impact of CMV on the composition of the hundreds of bioactive factors in human milk has not been tested. Here, we utilize a cohort of exclusively breastfeeding full-term mother-infant pairs...
Identifying rare variants inconsistent with identity-by-descent in population-scale whole-genome sequencing data
Analyses of genetic variation typically assume that rare variants within a population are inherited from a single common ancestral event identity-by-descent (IBD). However, there are genetic and technical processes through which rare variants in population genetic data may deviate from this simple evolutionary model, including recurrent mutations, gene conversions and genotyping error. All these processes can decrease the expected length of shared background haplotype surrounding a rare variant...
Disparities in Genetic Testing for Neurologic Disorders
BACKGROUND AND OBJECTIVES: Genetic testing is now the standard of care for many neurologic conditions. Health care disparities are unfortunately widespread in the US health care system, but disparities in the utilization of genetic testing for neurologic conditions have not been studied. We tested the hypothesis that access to and results of genetic testing vary according to race, ethnicity, sex, socioeconomic status, and insurance status for adults with neurologic conditions.
The Importance of Offering Exome or Genome Sequencing in Adult Neuromuscular Clinics
Advances in gene-specific therapeutics for patients with neuromuscular disorders (NMDs) have brought increased attention to the importance of genetic diagnosis. Genetic testing practices vary among adult neuromuscular clinics, with multi-gene panel testing currently being the most common approach; follow-up testing using broad-based methods, such as exome or genome sequencing, is less consistently offered. Here, we use five case examples to illustrate the unique ability of broad-based testing to...
Assembly, stability, and dynamics of the infant gut microbiome are linked to bacterial strains and functions in mother's milk
The establishment of the gut microbiome in early life is critical for healthy infant development. Although human milk is recommended as the sole source of nutrition for the human infant, little is known about how variation in milk composition, and especially the milk microbiome, shapes the microbial communities in the infant gut. Here, we quantified the similarity between the maternal milk and the infant gut microbiome using 507 metagenomic samples collected from 195 mother-infant pairs at one,...
Genetic testing in adults with neurologic disorders: indications, approach, and clinical impacts
The role of genetic testing in neurologic clinical practice has increased dramatically in recent years, driven by research on genetic causes of neurologic disease and increased availability of genetic sequencing technology. Genetic testing is now indicated for adults with a wide range of common neurologic conditions. The potential clinical impacts of a genetic diagnosis are also rapidly expanding, with a growing list of gene-specific treatments and clinical trials, in addition to important...
Importance of human milk for infants in the clinical setting: Updates and mechanistic links
CONCLUSION: In this review, we affirm the importance of HM for all infants, especially clinical populations. An understanding of how HM composition is modulated by maternal and environmental factors is important to progress the field forward with respect to mechanistic links between HM biology and infant health outcomes.
Preimplantation Genetic Testing for Adult-Onset Neurodegenerative Disease: Considerations for Access, Utilization, and Counseling
Preimplantation genetic testing for monogenic conditions (PGT-M), formerly called preimplantation genetic diagnosis, is a specialized assisted reproduction technique that aims to reduce the risk of a pregnancy inheriting a monogenic condition. Despite calls to increase awareness and prepare neurologists for discussing PGT-M with patients and their families, no guidelines currently exist. When introducing PGT-M to those who may be interested in using it, there are major factors for discussion,...
Human Cytomegalovirus in breast milk is associated with milk composition, the infant gut microbiome, and infant growth
Human cytomegalovirus (CMV) is a highly prevalent herpesvirus that is often transmitted to the neonate via breast milk. Postnatal CMV transmission can have negative health consequences for preterm and immunocompromised infants, but any effects on healthy term infants are thought to be benign. Furthermore, the impact of CMV on the composition of the hundreds of bioactive factors in human milk has not been tested. Here, we utilize a cohort of exclusively breastfeeding full term mother-infant pairs...
Human milk variation is shaped by maternal genetics and impacts the infant gut microbiome
Human milk is a complex mix of nutritional and bioactive components that provide complete nutrition for the infant. However, we lack a systematic knowledge of the factors shaping milk composition and how milk variation influences infant health. Here, we used multi-omic profiling to characterize interactions between maternal genetics, milk gene expression, milk composition, and the infant fecal microbiome in 242 exclusively breastfeeding mother-infant pairs. We identified 487 genetic loci...
The Influence of Geographical Origin, Age, Sex, and Animal Husbandry on the Spontaneous Histopathology of Laboratory Cynomolgus Macaques (<em>Macaca Fascicularis</em>): A Contemporary Global and Multisite Review of Historical Control Data
To investigate the influence of geographical origin, age, and sex on toxicologically relevant spontaneous histopathology findings in cynomolgus macaques (Macaca fascicularis), we performed a comparative analysis of historical control data (HCD) from 13 test sites that included 3351 animals (1645 females and 1706 males) sourced from Mauritius, China, Vietnam, and Cambodia, aged from 2 to 9.5 years, and from 446 toxicology studies evaluated between 2016 and 2021. The most common findings were...