Using ant venom, Emory and Case Western Reserve University (Ohio) researchers have discovered a potential treatment for psoriasis, a common autoimmune skin disease.
Fire ant venom contains solenopsin, an organic compound that inflicts pain when humans are bitten, according to School of Medicine Professor of Dermatology Jack Arbiser. However, solenopsin also has properties similar to ceramide molecules, which provide the healthy barrier functions of the skin, said Shikha Rao, a postdoctoral fellow in Emory’s School of Medicine who collaborated with Arbiser on the project.
Arbiser’s team developed an analog compound resembling natural ceramide molecules of fire ant venom, Rao said. The compound may be able to reduce skin irritation caused by psoriasis, according to Nicole Ward, an associate professor of dermatology at Case Western who collaborated with Arbiser.
Psoriasis occurs when skin cells grow too rapidly, causing skin to become thick, red and scaly, according to the Centers for Disease Control and Prevention (CDC). The condition can lead to psoriatic arthritis, which is found in 10 to 20 percent of psoriasis patients. Psoriasis currently affects 2.5 to 6 million patients in the United States, according to Arbiser’s study.
Existing treatments and topical steroid creams for psoriasis cause side effects, such as increased susceptibility to bruising and thinning of skin, Ward said. Patients can also develop resistances to the creams after long-term use, according to the study.
“It’s really a surprising result,” Arbiser said of the study. “Who would think ant venom could do anything good? I always say, ‘God is a better chemist than we are.’”
Arbiser and his team developed the ceramide analog compound in 2012 and 2013. They then sent the compound to Ward and her team at Case Western, who work with mice genetically programmed to develop psoriasis. Undergraduate students at Case Western began testing the compound on mice by applying it to their skin twice a day for 28 days, Ward said.
The compound decreases cellular production of the interleukin (IL)-22 protein, which causes inflammation, according to the study. It also increased production of IL-12, an anti-inflammatory protein.
Mice treated with the solenopsin compound had a 30 percent reduction in skin thickness when compared with mice not treated by the compound, the study showed.
Ward and Rao said they believe that the treatment could also lead to treatments for other skin conditions with similar inflammations.
Psoriasis and skin cancer share the IL-22 protein as well as similarities of development and symptoms, and Arbiser is working on a grant to see if his compound can prevent skin cancer in mice, according to Arbiser.
The next goal is to translate the study’s findings into a treatment for human patients, Ward said. She hopes to culture psoriasis samples to ensure that the treatment works on psoriasis cells before beginning clinical trials on humans.
After the creation of the ceramide analog, Arbiser suggested a collaboration with Ward. The undergraduates in Ward’s lab began the tests on mice in 2016, and the study was published September 2017.
The study began as a collaboration between researchers at Emory and the University of Georgia (UGA) 15 years ago. UGA researchers were studying whether spraying a similar compound on fire ants would convince the ants that they had already developed venom, so they would produce fewer toxins, Arbiser said. The tests were unsuccessful, but they led to the discovery that solenopsin resembles ceramides, which helped Arbiser develop the topical cream.
Arbiser added that his team must partner with a company in the pharmaceutical industry in order to receive the licensing and regulatory information necessary to conduct clinical trials on human subjects.
Arbiser’s goals are to determine if the treatment may be able to decrease inflammation caused by skin cancer and to determine if the treatment has the same healing effects on human psoriasis patients as it did on mice with psoriasis. The findings may be linked to each other, he added.
“The whole scientific process goes a lot slower than [my team and I] would like, but if the treatment works in mouse models of skin cancers, we may be able to get even more interest from companies so that we can try the treatments in human clinical trials too,” Arbiser said.
Ward said that she hopes to see further results from the treatment.
“This has been a long collaboration, and we’re super excited about our results, so I’m excited about what we will be able to do next,” Ward said.