Ijeoma Okeigwe1, Serdar Bulun1, Shimeng Liu1, Alfred W Rademaker2, John S Coon1, Stacy Kujawa1, Jared Robins1, Ping Yin1. 1. Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois. 2. Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
Abstract
CONTEXT: Uterine leiomyoma (fibroids) are the most common tumors in women. Recently, perilipin-2 (PLIN2) was identified as a critical target gene of the progesterone receptor; however, its function in the pathogenesis of fibroids is unknown. OBJECTIVE: To determine the function of PLIN2 in leiomyoma cells. DESIGN: Tissue and primary cells from leiomyoma and myometrium were analyzed. PLIN2 function in leiomyoma was assessed using small interfering RNA. RNA-sequencing was performed to identify genome-wide effects of PLIN2 depletion. Metabolic activity was measured using the Seahorse XF96 analyzer. Real-time quantitative PCR and immunoblotting were also performed. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-one premenopausal women undergoing surgery for fibroids. MAIN OUTCOME MEASURES: Gene expression, oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and cell proliferation. RESULTS: PLIN2 gene expression was 2.4-fold lower in leiomyoma compared with adjacent myometrium, suggesting a link between PLIN2 deficiency and fibroids. A total of 3877 genes were differentially expressed after PLIN2 knockdown. Gene ontology analysis identified metabolism as the second-highest biological process affected by PLIN2 depletion. OCR (mitochondrial respiration) and ECAR (glycolysis) were significantly upregulated after PLIN2 knockdown; PLIN2-depleted cells had a greater basal metabolic activity and higher metabolic stress response. Cell proliferation was also significantly increased after PLIN2 knockdown. CONCLUSIONS: PLIN2 depletion increases mitochondrial respiration and glycolysis, suggesting that PLIN2 is a critical regulator of metabolic function in leiomyoma cells. PLIN2 deficiency also reprograms leiomyoma cells to a proproliferative phenotype. These findings introduce metabolomics as an area to explore to better understand leiomyoma tumorigenesis.
CONTEXT: Uterine leiomyoma (fibroids) are the most common tumors in women. Recently, perilipin-2 (PLIN2) was identified as a critical target gene of the progesterone receptor; however, its function in the pathogenesis of fibroids is unknown. OBJECTIVE: To determine the function of PLIN2 in leiomyoma cells. DESIGN: Tissue and primary cells from leiomyoma and myometrium were analyzed. PLIN2 function in leiomyoma was assessed using small interfering RNA. RNA-sequencing was performed to identify genome-wide effects of PLIN2 depletion. Metabolic activity was measured using the Seahorse XF96 analyzer. Real-time quantitative PCR and immunoblotting were also performed. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-one premenopausal women undergoing surgery for fibroids. MAIN OUTCOME MEASURES: Gene expression, oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and cell proliferation. RESULTS:PLIN2 gene expression was 2.4-fold lower in leiomyoma compared with adjacent myometrium, suggesting a link between PLIN2 deficiency and fibroids. A total of 3877 genes were differentially expressed after PLIN2 knockdown. Gene ontology analysis identified metabolism as the second-highest biological process affected by PLIN2 depletion. OCR (mitochondrial respiration) and ECAR (glycolysis) were significantly upregulated after PLIN2 knockdown; PLIN2-depleted cells had a greater basal metabolic activity and higher metabolic stress response. Cell proliferation was also significantly increased after PLIN2 knockdown. CONCLUSIONS:PLIN2 depletion increases mitochondrial respiration and glycolysis, suggesting that PLIN2 is a critical regulator of metabolic function in leiomyoma cells. PLIN2 deficiency also reprograms leiomyoma cells to a proproliferative phenotype. These findings introduce metabolomics as an area to explore to better understand leiomyoma tumorigenesis.
Authors: Deborah E Ikhena; Shimeng Liu; Stacy Kujawa; Ecem Esencan; John S Coon; Jared Robins; Serdar E Bulun; Ping Yin Journal: J Clin Endocrinol Metab Date: 2018-05-01 Impact factor: 5.958