Caroline Helen Johnson, PhD

Assistant Professor of Epidemiology (Environmental Health Sciences)

Research Interests

Environmental Exposure; Mass Spectrometry; Metabolomics

Public Health Interests

Colorectal Cancer; Environmental Health

Research Organizations

School of Public Health: Caroline Johnson Lab

Virus and Other Infection-associated Cancers

Extensive Research Description

Microbial metabolites and colon cancer

Colon cancers that present on the right versus the left side of the colon have significantly worse prognosis for the patient. A recent discovery revealed that right-sided colon cancers (RCCs) harbor mucosal bacterial biofilms, whereas left-sided colon cancers (LCC) are predominantly devoid of biofilms. These biofilms are associated with increased cellular proliferation and inflammation even in normal colon tissues. Using mass spectrometry-based metabolomics, we investigated the metabolism of colon cancers with and without biofilms, and observed a correlation between increased diacetylspermine production and biofilm presence on RCCs. Using antibiotic treatment, IHC, and stable isotope-assisted metabolomics we showed that diacetylspermine is an end product of polyamine metabolism produced by bacterial biofilms. We thus hypothesized that microbiota use host-derived polyamines to form biofilms. It is still not known why biofilms only form only on RCC, but it could be due to other factors such as diet and genetic predisposition.

Therefore, we aim are to examine the influence of these factors in LCC and RCC pathogenicity by investigating the roles of dietary metabolites, microbial communities and genetic predisposition.

Human exposure to chemicals in artificial turf

Artificial turf fields contain crumb rubber infill recycled from tires. Studies have shown that rubber crumb taken from synthetic turf fields contain hazardous materials such as volatile organic chemicals, including polycyclic aromatic hydrocarbons, and semi volatile organic chemicals. Over the past several years, worldwide public health concerns have been raised about the potential exposure of athletes to these compounds through inhalation, ingestion, or dermal contact with tire crumb rubber. However, exposure and health data are very limited. Using mass spectrometry approaches and questionnaire data I will be assessing human exposure and short-term health effects of activities on artificial turf fields.

Assessment of chemical exposures and adverse pregnancy outcomes

Preterm birth can cause serious life-long health problems for the child, importantly it is the greatest contributor to neonatal mortality. One of the major causes for preterm birth is preterm premature rupture of the membranes (PPROM). The mechanism for PPROM is unknown but hypothesized to be caused by placental inflammation which induces early labor. One potential mediator of placental inflammation is exposure to environmental toxins.

In the Johnson Lab we will be developing methods for measuring exposures during pregnancy and identify novel mechanisms for PPROM. We will be using samples collected locally from the Yale Pregnancy and prediction Outcome Study (YPOPS) http://ypops.yale.edu/


Selected Publications

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Contact Info

Caroline Helen Johnson, PhD
Office Location
Laboratory of Epidemiology and Public Health (LEPH)
60 College Street, Rm 442

New Haven, CT 06510
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Johnson-lab

Diacetylspermine and its role in biofilm-associated colon cancer