Type 2 diabetic mice enter a state of spontaneous hibernation-like suspended animation following accumulation of uric acid

A Crucial Role of Adenosine Deaminase in Regulating Gluconeogenesis in mice

Adenosine deaminase (ADA) catalyzes the irreversible deamination of adenosine to inosine and regulates adenosine concentration. ADA ubiquitously expresses in various tissues to mediate adenosine receptor signaling. A significant increase in plasma ADA activity has been shown to be associated with the pathogenesis of type 2 diabetes mellitus (T2DM). Here we show that elevated plasma ADA activity is a compensated response to high level of adenosine in T2DM and plays an essential role in the regulation of glucose homeostasis. Supplementing with more ADA, instead of inhibiting ADA can reduces adenosine levels and decreases hepatic gluconeogenesis. ADA restores a euglycemic state and recovers functional islets in db/db and high-fat-STZ diabetic mice. Mechanistically, ADA catabolizes adenosine and increases Akt and FoxO1 phosphorylation independent of insulin action. ADA lowers blood glucose at a slower rate and longer duration compared to insulin, delaying or blocking the incidence of insulinogenic hypoglycemia shock. Finally, ADA suppresses gluconeogenesis in fasted mice and insulin-deficient diabetic mice, indicating the ADA regulating gluconeogenesis is a universal biological mechanism. Overall, these results suggest that ADA is expected to be a new therapeutic target for diabetes.

ATP-induced hypothermia improves burn injury and relieves burn pain in mice

Thermal burn injury is a severe and life-threatening form of trauma that presents a significant challenge to clinical therapy. Therapeutic hypothermia has been shown to be beneficial in various human pathologies. Adenosine triphosphate (ATP) induces a hypothermic state that resembles hibernation-like suspended animation in mammals. This study investigates the potential protective role of ATP-induced hypothermia in thermal burn injury. Male C57BL/6 mice underwent a sham procedure or third-degree burn, and ATP-induced hypothermia was applied immediately or 1 h after burn injury. Our results show that ATP-induced hypothermia significantly improved burn depth progression and reduced collagen degradation. Moreover, hypothermia induced by ATP alleviated burn-induced hyperinflammatory responses and oxidative stress. Metabolomic profiling revealed that ATP-induced hypothermia reversed the shifts of metabolic profiles of the skin in burn mice. In addition, ATP-induced hypothermia relieved nociceptive and inflammatory pain, as observed in the antinociceptive test. Our findings suggest that ATP-induced hypothermia attenuates burn injury and provides new insights into first-aid therapy after thermal burn injury.

Effects of Exogenous ATP on Melanoma Growth and Tumor Metabolism in C57BL/6 Mice

Altered energy metabolism (glucose, lipid, amino acid) is a hallmark of cancer growth that provides the theoretical basis for the development of metabolic therapies as cancer treatments. ATP is one of the major biochemical constituents of the tumor microenvironment. ATP promotes tumor progression or suppression depending on various factors, including concentration and tumor type. Here we evaluated the antitumor effect of extracellular ATP on melanoma and the potential underlying mechanisms. A subcutaneous tumor model in mice was used to investigate the antitumor effects of ATP. Major lymphocyte cell changes and intratumoral metabolic changes were assessed. Metabolomic analysis (1H nuclear magnetic resonance spectroscopy) was performed on tumor samples. We measured the activities of lactate dehydrogenase A (LDHA) and LDHB in the excised tumors and serum and found that ATP and its metabolites affected the proliferation of and LDHA activity in B16F10 cells, a murine melanoma cell line. In addition, treatment with ATP dose-dependently reduced tumor size in melanoma-bearing mice. Moreover, flow cytometry analysis demonstrated that the antitumor effect of ATP was not achieved through changes in T-cell or B-cell subsets. Metabolomics analysis revealed that ATP treatment simultaneously reduced multiple intratumoral metabolites related to energy metabolism as well as serum and tumor LDHA activities. Furthermore, both ATP and its metabolites significantly suppressed both tumor cell proliferation and LDHA activity in the melanoma cell line. Our results in vivo and in vitro indicate that exogenous ATP inhibits melanoma growth in association with altered intratumoral metabolism.