Elizabeth Kopras

Developing a bidirectional academic-community partnership with an Appalachian-American community for environmental health research and risk communication.

Background: Marietta, Ohio, is an Appalachian-American community whose residents have long struggled with understanding their exposure to airborne manganese (Mn). Although community engagement in research is strongly endorsed by the National Institutes of Health and the National Institute of Environmental Health Sciences in particular, little has been documented demonstrating how an academic–community partnership that implements the community-based participatory research (CBPR) principles can be created and mobilized for research. Objectives: We created a bidirectional, academic–community partnership with an Appalachian-American community to a) identify the community’s thoughts and perceptions about local air quality, its effect on health, and the perception of risk communication sources and b) jointly develop and conduct environmental health research. Methods: We formed a community advisory board (CAB), jointly conducted pilot research studies, and used the results to develop a community-driven research agenda. Results: Persons in the community were “very concerned” to “concerned” about local air quality (91%) and perceived the air quality to have a direct impact on their health and on their children’s health (93% and 94%, respectively). The CAB identified the primary research question: “Does Mn affect the cognition and behavior of children?” Although the community members perceived research scientists as the most trusted and knowledgeable regarding risks from industrial emissions, they received very little risk information from research scientists. Conclusions: Engaging a community in environmental health research from its onset enhanced the quality and relevance of the research investigation. The CBPR principles were a useful framework in building a strong academic–community partnership. Because of the current disconnect between communities and research scientists, academic researchers should consider working collaboratively with community-based risk communication sources.

Cellular distribution of secretin receptor expression in rat pancreas

Secretin is an important regulator of pancreatic function, but the molecular basis of its actions is not well understood. We have, therefore, used in situ autoradiography, photoaffinity labeling, and RNase protection assays with healthy rat pancreas, dispersed acinar cells, and pancreas depleted of acinar cells to explore the cellular distribution and molecular identity of high-affinity secretin receptors in this complex organ. The autoradiographic examination of125I-labeled [Tyr10]rat secretin-27 binding to normal pancreas demonstrated saturable and specific high-affinity binding sites on both acinar and duct cells, with a uniform lobular distribution, but with no binding above background over islets or vascular structures. Photoaffinity labeling demonstrated that the ductular binding site in acinar cell-depleted copper-deficient rat pancreas represented the same glycoprotein with a molecular weight of 50,000-62,000 that was present on acinar cells. RNase protection assays confirmed the molecular identity of the secretin receptors expressed on these distinct cells. The apparent absence or extreme low density of similar secretin receptors on islets and pancreatic vascular structures suggests that the pharmacological effects of secretin on those cells may either be indirect or mediated by another secretin family receptor that recognizes this hormone with lower affinity.Secretin is an important regulator of pancreatic function, but the molecular basis of its actions is not well understood. We have, therefore, used in situ autoradiography, photoaffinity labeling, and RNase protection assays with healthy rat pancreas, dispersed acinar cells, and pancreas depleted of acinar cells to explore the cellular distribution and molecular identity of high-affinity secretin receptors in this complex organ. The autoradiographic examination of 125I-labeled [Tyr10]rat secretin-27 binding to normal pancreas demonstrated saturable and specific high-affinity binding sites on both acinar and duct cells, with a uniform lobular distribution, but with no binding above background over islets or vascular structures. Photoaffinity labeling demonstrated that the ductular binding site in acinar cell-depleted copper-deficient rat pancreas represented the same glycoprotein with a molecular weight of 50,000-62,000 that was present on acinar cells. RNase protection assays confirmed the molecular identity of the secretin receptors expressed on these distinct cells. The apparent absence or extreme low density of similar secretin receptors on islets and pancreatic vascular structures suggests that the pharmacological effects of secretin on those cells may either be indirect or mediated by another secretin family receptor that recognizes this hormone with lower affinity.

Actions of endocrine disrupting chemicals on stem/progenitor cells during development and disease

Development and fate of the stem cell are regulated by extrinsic signals from the environment. Endocrine-disrupting chemicals which perturb hormonal signaling in utero and during early childhood may cause deregulation of multiple developmental processes, ranging from breakdown of stem cell niche architecture, developmental reprograming and altered stem cell fate to impaired organ and gonad development and sexual differentiation. Therefore, study of the environmental effects on stem cell integrity and normal development is a new and emerging focus for developmental biologists and cell toxicologists. When combined with new human and mouse stem cell-based models, stem cell differentiation dynamics can be studied in more biologically relevant ways. In this study, we review the current status of our understanding of the molecular mechanisms by which endocrine disruptors alter embryonic stem cell and adult stem/progenitor cell fate, organ development, cancer stem cell activity, and tumorigenesis.

Spontaneous Pneumothoraces in Patients with Birt–Hogg–Dubé Syndrome

Rationale: Spontaneous pneumothorax is a common complication of Birt‐Hogg‐Dubé syndrome (BHD). Objectives: The optimal approach to treatment and prevention of BHD‐associated spontaneous pneumothorax, and to advising patients with BHD regarding risk of pneumothorax associated with air travel, is not well established. Methods: Patients with BHD were recruited from the Rare Lung Diseases Clinic Network and the BHD Foundation and surveyed about disease manifestations and air travel experiences. Results: A total of 104 patients completed the survey. The average age at diagnosis was 47 years, with an average delay from first symptoms of 13 years. Pulmonary cysts were the most frequent phenotypic manifestation of BHD, present in 85% of patients. Spontaneous pneumothorax was the presenting manifestation that led to the diagnosis of BHD in 65% of patients, typically after the second episode (mean, 2.4 episodes). Seventy‐nine (76%) of 104 patients had at least one spontaneous pneumothorax during their lifetime, and 82% had multiple pneumothoraces. Among patients with multiple pneumothoraces, 73% had an ipsilateral recurrence, and 48% had a subsequent contralateral spontaneous pneumothorax following a sentinel event. The mean ages at first and second pneumothoraces were 36.5 years (range, 14‐63 yr) and 37 years (range, 20‐55 yr), respectively. The average number of spontaneous pneumothoraces experienced by patients with a sentinel pneumothorax was 3.6. Pleurodesis was generally performed after the second (mean, 2.4) ipsilateral pneumothorax and reduced the ipsilateral recurrence rate by half. A total of 11 episodes of spontaneous pneumothorax occurred among eight patients either during or within the 24‐hour period following air travel, consistent with an air travel‐related pneumothorax rate of 8% per patient and 0.12% per flight. Prior pleurodesis reduced the occurrence of a subsequent flight‐related pneumothorax. Conclusions: Spontaneous pneumothorax is an important, recurrent manifestation of pulmonary involvement in patients with BHD, and pleurodesis should be considered following the initial pneumothorax to reduce the risk of recurrent episodes. In general, in patients with BHD, pneumothorax occurs in about 1‐2 per 1,000 flights, and the risk is lower among patients with a history of prior pleurodesis.

A Phase II Clinical Trial of an Aromatase Inhibitor for Postmenopausal Women with Lymphangioleiomyomatosis

Rationale: Lymphangioleiomyomatosis (LAM) is a progressive cystic lung disease that predominantly affects women and can worsen with pregnancy, estrogen treatment, and the menstrual cycle, suggesting an important role for estrogen in disease pathogenesis. Objectives: To assess the efficacy and safety of the aromatase inhibitor letrozole in the treatment of LAM. Methods: Seventeen postmenopausal women with LAM were enrolled in this phase II trial and randomized to receive letrozole 2.5 mg daily (n = 9) or placebo (n = 8) for a period of 12 months. Five patients in each group were also taking sirolimus at baseline and remained on the drug throughout the treatment period. Lung function, exercise capacity, quality of life, and serum vascular endothelial growth factor D (VEGF‐D) were measured at baseline and at 3‐month intervals. Results: Fifteen patients completed the study. Two patients withdrew. There were no differences in adverse events in the letrozole and placebo groups. The target enrollment of 25 patients per arm was not met, so the efficacy of letrozole could not be assessed as planned. After adjusting for sirolimus use, we found that the rate of change in FEV1 for all subjects was ‐3 ± 3 ml/mo (P = 0.4), and for serum VEGF‐D, the rate of change was ‐0.024 ± 0.009 pg/ml/mo (P = 0.015), showing a steeper decline in the letrozole group (‐0.029 ± 0.013; P = 0.025). All patients who were taking sirolimus had a reduction in VEGF‐D levels from baseline to the last visit, compared with only half of the patients who were not taking sirolimus. In a post hoc analysis, eight matched letrozole‐treated‐placebo‐treated pairs were constructed, six of which demonstrated better FEV1 improvement for the letrozole‐treated patients. Conclusions: Letrozole treatment appears to be safe and well tolerated in postmenopausal patients with LAM, including those taking sirolimus. Enrollment in this trial was compromised by the publication of an effective treatment (sirolimus) in the same month as the study opened, resulting in limited power to detect treatment effects. Post hoc matched pairs exploration studies provide tentative support for additional studies of letrozole in LAM. Considering the reduced rate of lung function decline in postmenopausal patients, future studies will likely require enhanced study designs, such as selective enrollment of those with prognostic biomarkers predictive of decline. Clinical trial registered with www.clinicaltrials.gov (NCT01353209).

Tuberin Regulates Prostaglandin Receptor-mediated Viability, via Rheb, in mTORC1-hyperactive Cells.

Tuberous sclerosis complex (TSC) is a tumor-suppressor syndrome affecting multiple organs, including the brain, skin, kidneys, heart, and lungs. TSC is associated with mutations in TSC1 or TSC2, resulting in hyperactivation of mTOR complex 1 (mTORC1). Clinical trials demonstrate that mTORC1 inhibitors decrease tumor volume and stabilize lung function in TSC patients; however, mTOR inhibitors are cytostatic not cytocidal, and long-term benefits and toxicities are uncertain. Previously, we identified rapamycin-insensitive upregulation of cyclooxygenase 2 (PTGS2/COX2) and prostaglandin E2 (PGE2) production in TSC2-deficient cells and postulated that the action of excess PGE2 and its cognate receptors (EP) contributes to cell survival. In this study, we identify upregulation of EP3 (PTGER3) expression in TSC2-deficient cells, TSC renal angiomyolipomas, lymphangioleiomyomatosis lung nodules, and epileptic brain tubers. TSC2 negatively regulated EP3 expression via Rheb in a rapamycin-insensitive manner. The EP3 antagonist, L-798106, selectively suppressed the viability of TSC2-deficient cells in vitro and decreased the lung colonization of TSC2-deficient cells. Collectively, these data reveal a novel function of TSC2 and Rheb in the regulation of EP3 expression and cell viability. Implications: Therapeutic targeting of an aberrant PGE2-EP3 signaling axis may have therapeutic benefit for TSC patients and for other mTOR-hyperactive neoplasms. Mol Cancer Res; 15(10); 1318–30. ©2017 AACR.