New research on the X chromosome from the School of Veterinary Medicine points to an abnormality in the immune system’s T cells as a possible contributing factor in lupus and other autoimmune diseases.
The autoimmune disease lupus, which can cause fatigue, a facial rash, and joint pain, strikes females far more often than males. Eight-five percent of people with lupus are female, and their second X chromosome seems partly to blame. According to a new study by Penn researchers, females with lupus don’t fully “silence” their second X chromosome in the immune system’s T cells, leading to abnormal expression of genes linked to that chromosome.
The work, led by Montserrat Anguera of the School of Veterinary Medicine and published in the journal JCI Insight, is the first to connect disruptions in maintaining X chromosome inactivation in T cells to lupus. It also suggests that changes to the nuclear structure in the inactive X chromosome of T cells may play a part in the genetic missteps that can arise in lupus—the first time that nuclear organization has been noted as a feature of this disease.
“In normal circumstances, the inactive X should be silenced, and what we show is, in lupus, it’s not,” says Anguera, a biologist at Penn Vet. “And it’s ultimately affecting gene expression.”
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