Breaking News
February 20, 2019 - Over Half of Hip Replacements Expected to Last 25 Years
February 20, 2019 - Microscopic eye movements affect how we see contrast
February 20, 2019 - Computer vs. patient: Fighting for residents’ attention | News Center
February 20, 2019 - New “Smart Drug” Shows Promise for Metastatic Triple-Negative Breast Cancer
February 20, 2019 - Researchers develop large-scale window material for high-efficiency PM2.5 capture
February 20, 2019 - Widespread confusion among consumers on food date labels lead to unnecessary discards
February 20, 2019 - Researchers unlock plant’s secret of producing specialized metabolites
February 20, 2019 - Newly released national framework identifies obstacles to improving EMS systems
February 20, 2019 - Exercise can shift human body clock depending on time when people work out
February 20, 2019 - Female adolescent blood donors more likely to have iron deficiency and related anemia
February 20, 2019 - Rubicon level linked to inhibition of autophagic process
February 20, 2019 - Researchers find potential therapeutic strategy to treat Alzheimer’s
February 20, 2019 - New forms of older anti-cancer agent appear to enhance immune response to fight melanoma
February 20, 2019 - Health Tip: Eat Less Saturated Fat
February 20, 2019 - Sleeping in contact lenses puts you at risk of dangerous infection
February 20, 2019 - “We should study that!”: How a nurse-scientist found her passion
February 20, 2019 - Cervical microbiome may influence HPV infection more than previously thought
February 20, 2019 - Sausage mislabeling in Canada is down, new study finds
February 20, 2019 - Study shows blood pressure benefits of morning exercise for older overweight/obese adults
February 20, 2019 - New screening method could catch organ rejection much earlier without a biopsy needle
February 20, 2019 - Study may have important implications for refining parenting during child’s adolescence
February 20, 2019 - Study sheds new light on how antibiotic resistance genes are transferred between bacteria
February 20, 2019 - Chronic Wasting Disease may soon spread to humans, warns CDC
February 20, 2019 - Scientists identify new genetic causes linked to abnormal pregnancies and miscarriages
February 20, 2019 - Using LyoSpeed technology to avoid residual solvent when drying HPLC fractions
February 20, 2019 - Scientists join forces to identify a new approach to fight African sleeping sickness
February 20, 2019 - New screening tool more likely to identify sexual and labor exploitation of youth
February 20, 2019 - Newly licensed nurses work for long hours, also have a second paid job
February 20, 2019 - Physicists identify simple mechanism used by deadly bacteria to fend off antibiotics
February 20, 2019 - FDA Grants Priority Review to Genentech’s Personalized Medicine Entrectinib
February 20, 2019 - Exposure to chemicals before and after birth is associated with a decrease in lung function
February 20, 2019 - Neuroscientists reveal that simple brain region can guide complex feats of mental activity
February 20, 2019 - Study finds new link between food allergies and multiple sclerosis
February 20, 2019 - First gene therapy operation for macular degeneration is a success
February 20, 2019 - Physicians graduated outside the U.S. offer better care for Medicare patients with complex needs
February 20, 2019 - Study shows therapeutic potential of VEGF-A mRNA for regenerative angiogenesis in humans
February 20, 2019 - FDA Approves Keytruda (pembrolizumab) for the Adjuvant Treatment of Patients with Melanoma with Involvement of Lymph Node(s) Following Complete Resection
February 20, 2019 - Study identifies brain cells that modulate behavioral response to threats
February 20, 2019 - Researchers take closer look at how viruses bind cells and cause infection
February 20, 2019 - Newly developed gene therapy helps decelerate aging process
February 20, 2019 - Study suggests new treatment strategy for deadly brain cancer
February 20, 2019 - Scientists develop unique hybrid implant that imitates bone structure
February 20, 2019 - Push-ups can be tailored to meet specific needs of individuals
February 20, 2019 - Early-career job loss has long term health implications
February 20, 2019 - CVD Does Not Modify Depression-Mortality Link in Elderly
February 20, 2019 - Electrical activity early in fruit flies’ brain development could shed light on how neurons wire the brain
February 20, 2019 - Machine learning technique helps predict which asthma patients respond to corticosteroid therapy
February 20, 2019 - Self-reported sleep duration is a useful tool to measure sleep in children, study suggests
February 20, 2019 - T-cells play key role in how the body fights follicular lymphoma
February 20, 2019 - Study shows how 3D organization of genetic material helps perpetuate the species
February 20, 2019 - Researchers engineer stem cell with ‘suicide genes’ to induce cell death in all but beta cells
February 20, 2019 - Study reveals major sex differences in management of cardiovascular risk factors among U.S. adults
February 20, 2019 - Health Tip: Get Your Child to School on Time
February 20, 2019 - Shortcut strategy for screening compounds with clinical potentials for drug development
February 20, 2019 - Common acid reflux drugs tied to elevated risk for kidney disease
February 20, 2019 - Microbiome could be culprit when good drugs do harm
February 20, 2019 - Prenatal exposure to forest fires causes stunted growth in children
February 20, 2019 - Gene therapy restores hearing in mice with congenital genetic deafness
February 20, 2019 - First molecular test predicts treatment response for kidney cancer
February 20, 2019 - New method for improved visualization of single-cell RNA- sequencing data
February 20, 2019 - Researchers capture altered brain activity patterns of Parkinson’s in mice
February 20, 2019 - A possible blood test for detecting Alzheimer’s disease before symptoms show
February 20, 2019 - Primary care physicians associated with longevity, new research finds
February 19, 2019 - New study identifies many key lessons to establish sanctioned safe consumption sites
February 19, 2019 - Single CRISPR treatment can safely and stably correct genetic disease
February 19, 2019 - Multinational initiative to study familial primary distal renal tubular acidosis
February 19, 2019 - Breakthrough study highlights the promise of cell therapies for muscular dystrophy
February 19, 2019 - Subsymptom Threshold Exercise Speeds Concussion Recovery
February 19, 2019 - Midline venous catheters – infants: MedlinePlus Medical Encyclopedia
February 19, 2019 - Searching for side effects
February 19, 2019 - Humanity is all right, probably, although human extinction remains quite possible, researcher says
February 19, 2019 - Having Anesthesia Once as a Baby Does Not Cause Learning Disabilities, New Research Shows
February 19, 2019 - Anti-cancer immunotherapy could be used to fight HIV
February 19, 2019 - Customized Micropatterning for Improved Physiological Relevance
February 19, 2019 - Unique gene therapy approach paves new way to tackle rare, inherited diseases
February 19, 2019 - Activating gene that helps excite neurons reverses depression in male mice
February 19, 2019 - Science Puzzling Out Differences in Gut Bacteria Around the World
February 19, 2019 - Cells that destroy the intestine
February 19, 2019 - On recovery, vulnerability and ritual: An exhibit in white
February 19, 2019 - Scientific Duo Gets Back To Basics To Make Childbirth Safer
Biochemist, physicist team to see antibacterial TCS deform mitochondria

Biochemist, physicist team to see antibacterial TCS deform mitochondria

image_pdfDownload PDFimage_print
Credit: University of Maine

Grocery shopping can be an illuminating chore for a toxicologist.

Julie Gosse, a University of Maine associate professor of molecular and biomedical sciences, has scanned the supermarket aisles for products that contain triclosan (TCS), a synthetic antibacterial agent.

Since the ’90s, TCS has been in a slew of consumer products, including facial cleansers, toothpaste, mouthwash and hand sanitizers.

For years, Gosse has studied TCS, which for decades also has been used as a hospital scrub to reduce risk of infection.

She became interested in examining triclosan when listening to a talk by Environmental Protection Agency scientist Susan Richardson and noting that the molecular structure of TCS resembles the molecular structure of dioxins, which are toxic environmental pollutants.

In 2016, the Food and Drug Administration banned triclosan from consumer bar soaps, liquid soaps and body washes. At that time, the FDA challenged manufacturers to either prove TCS was more effective at killing germs than plain soap, or to remove it from their soap product within a year.

The antimicrobial agent, which is readily absorbed into the skin and the lining of the mouth, has recently been found to have detrimental effects on human fertility, development, thyroid function and immunology, and has been associated with increased occurrence of asthma.

Then, about six months ago, the FDA also announced a ban on products such as hand washes and antiseptic rubs containing TCS that are used in medical settings.

There’s no such ban on Colgate Total, the popular toothpaste that contains TCS. That’s because it’s been found to be more effective at treating gingivitis than toothpaste without it.

Gingivitis is an important health concern as it can lead to tooth loss. And research has indicated the bacteria that causes periodontitis can enter a person’s bloodstream and harm the heart and lungs.

Gosse understands why people with gingivitis would use Colgate Total; she just wants millions of people without gingivitis who also use the product to be aware of possible risks.

“Our job is to do the best science we can do and make people aware,” she says. “As scientists, we communicate our findings, and the public or companies or government decides what they should do.”

Triclosan also remains in certain “antibacterial” products not under the FDA’s control—such as cutting boards and baby products.

In various studies, Gosse and colleagues have made multiple discoveries about TCS. In conducting their research, they’ve used TCS dosages that correspond to doses people are exposed to when brushing their teeth or showering with products that contain the antimicrobial.

One discovery is that TCS is a mitochondrial uncoupler. That is, it’s toxic to mitochondria, which are the energy powerhouses of cells. When mitochondria are deformed or shut down, they can’t make the energy that cells need to perform functions—including immune defense.

One study outside of UMaine found increased TCS levels in mothers of babies with birth defects. Another study, also outside of UMaine, indicated mitochondrial dysfunction was linked to cognitive decline in monkeys.

Gosse determined TCS is 30 to 60 times more toxic than 2,4-dinitrophenol, another uncoupler once used in diet drugs (and to make explosives) that was banned in the late 1930s because it resulted in death or severe side effects.

In UMaine’s most recent study, the team sought to determine the mechanisms underlying TCS disruption of mitochondrial function and mast cell signaling.

To do so, Gosse and her doctoral student Lisa Weatherly teamed with professor of physics Sam Hess and his doctoral student Andrew Nelson.

Hess invented a fluorescence photoactivation localization microscopy (FPALM) technique that allows researchers to witness triclosan’s deformation of live cells’ mitochondria, in real time.

Mitochondria are generally an elongated oval shape. TCS either deforms mitochondria from an oval to a doughnut shape or breaks up the energy powerhouses, within minutes.

Gosse has pored through conference proceedings and publications and believes the UMaine team is the first to use super-resolution microscopy work in the field of toxicology.

Following up on the microscope findings, Gosse and her team determined the biochemical mechanisms that underlie triclosan’s fission of mitochondria—including generation of damaging reactive oxygen species.

TCS, says Gosse, also inhibits cellular cytoskeletons, which are microscopic networks of protein filaments and tubules in the cytoplasm of living cells. Cytoskeletons help the cell move, transport cargo, and carry out many other tasks essential for health.

When TCS inhibits cytoskeletons, it inhibits mast cell function. Mast cells are part of the immune and nervous systems that, when stimulated, release chemicals that play many roles in the body, including antimicrobial defense, cancer and even emotional regulation.

Mast cells are in most human tissues, including the lining of the mouth and in skin—both of which absorb TCS. So, when mast cells are inhibited, problems may arise.

The Gosse lab also found that, of several cell types tested, primary human skin cells were the cells most harmed by TCS.

The UMaine team’s most recent findings were published in April in the article “Antimicrobial agent triclosan disrupts mitochondrial structure, revealed by super-resolution microscopy, and inhibits mast cell signaling via calcium modulation” in Toxicology and Applied Pharmacology.

In addition to Gosse, Hess, Weatherly and Nelson, UMaine researchers participating in the study included graduate students Juyoung Shim and Andrew Hart and undergraduates Erik Gerson and Abigail Riitano; as well as Timothy Ryan and Jaime de Juan-Sanz of Weill Cornell Medicine; and Roger Sher of Stony Brook University.

Funding was provided by an R15 Academic Research Enhancement Award which supports meritorious research and exposes undergraduate and graduate students to hands-on research—from the National Institutes of Health. Graduate School of Biomedical Science and Engineering student Weatherly was supported by UMaine’s Chase Distinguished Research Assistantship and Michael J. Eckardt Dissertation Fellowship.

Thanks to research conducted by Gosse and other scientists, consequences of exposure to triclosan are becoming better understood and known.

And thanks to Hess’ FPALM technique, the field of toxicology has a powerful new tool for understanding chemical effects on human health.

Triclosan, though, is one of about 80,000 synthetic chemicals that people are regularly exposed to, says Gosse. And many of their long-term effects have not been studied.


Explore further:
Common antimicrobial inhibits immune cell function

More information:
Lisa M. Weatherly et al. Antimicrobial agent triclosan disrupts mitochondrial structure, revealed by super-resolution microscopy, and inhibits mast cell signaling via calcium modulation, Toxicology and Applied Pharmacology (2018). DOI: 10.1016/j.taap.2018.04.005

Journal reference:
Toxicology and Applied Pharmacology

Provided by:
University of Maine

Tagged with:

About author

Related Articles