Genetically encoded fluorescent biosensors that detect changes in ATP levels in live cells have enabled the discovery of novel roles for ATP in cellular processes and signaling. Many of these available ATP biosensors have a limited dynamic range, or have ATP affinities that are not suitable for sensing the physiological concentrations of ATP in mammalian cells. To address these limitations, we developed a FRET-based ATP biosensor with enhanced dynamic range and signal to noise ratio, eATeam. Using eATeam, we uncovered distinct spatiotemporal dynamics of ATP changes upon inhibition of cellular energy production. We also developed dimerization-dependent GFP and RFP-based ATP biosensors with enhanced dynamic ranges compared to the current standard in the field. Using the single-color ATP biosensors, we visualized the complex interplay between AMPK activity, ATP, lactate, and calcium by multiplexed imaging in single cells. This palette of ATP sensors expands the toolbox for interrogating subcellular ATP regulation and metabolic signaling in living cells.

6549 Background: The incidence of adolescent and young adults (AYAs) with cancer continues to increase. The psychosocial burden of early cancer diagnosis within this unique AYA population remains poorly characterized. Without proper resources, these patients are likely to seek care in the acute care setting. For AYA patients, we evaluated the impact of malignancy on concurrent diagnosis with depression and on presenting to the emergency department (ED) with intentional self-injury. We further described the influence of concurrent depression diagnosis on hospital admission and extended length of stay (LOS) for AYA cancer patients. Methods: From the National Emergency Department Sample (NEDS), we identified patients between 15-39 years who presented to an ED in 2019. Diagnosis of cancer and depression were identified using International Classification of Diseases, 10th Revision coding. Separate multivariable logistic regressions evaluated the impact of cancer diagnosis on concurrent depression diagnosis and on presenting with intentional self-injury. For the subset of AYA cancer patients, multivariable logistic regressions evaluated the impact of depression on hospital admission and extended LOS ( > 14 days). Results: We identified 10,570,148 AYA patients, and 35,035 had cancer (0.33%). Among AYA cancer patients, average age was 31 and the cohort skewed White (48.7%), female (58.1%), and with Medicaid insurance (48.4%). The prevalence of depression among AYA cancer patients was 9.6% vs. 4.4% for patients without cancer. On multivariable regression, AYA cancer patients had a 46% increased odds of depression diagnosis (odds ratio (OR), 95% confidence interval (CI): 1.46. [1.43-1.49] P < 0.01) and 32% increased odds of intentional self-injury (OR, 95% CI: 1.32 [1.19-1.47] P < 0.01) when compared to patients without cancer. Additional significant factors associated with depression diagnosis among AYA cancer patients were White race, female gender, and Medicaid insurance. Within AYA cancer patients, a concurrent diagnosis with depression was associated with ̃3-fold increased odds of hospital admission (OR, 95% CI: 3.02 [2.90-3.14] P < 0.01) and a 31% increased odds of extended LOS (OR, 95% CI: 1.31 [1.23-1.39] P < 0.01). Conclusions: From this national sample, we found a significant association between cancer diagnosis and depression within AYA patients, with cancer diagnosis also increasing the risk of intentional self-injury. Furthermore, AYA cancer patients diagnosed with depression had increased risk of both hospital admission and extended LOS. Our results underscore the potential gap in psychological care for AYA cancer patients and highlight the need for stronger mental health resources for this at-risk population.