A Rare Coexistence of Pheochromocytoma and Parkinson\u27s Disease With Diagnostic Challenges

We herein report a case of pheochromocytoma occurring in the course of Parkinson’s disease. The coexis-tence of these two disease is extremely rare, with only four cases hitherto reported across the public data-bases. It is also noteworthy that biochemical tests, which are critical for the diagnosis of pheochromocytoma, are severely confounded by dopaminergic medications fo r Parkinson’s disease, highlighting the importance of image-based modalities in this setting. We further attemp ted to gain insight into the potential molecular mechanisms, proposing that hypoxia-inducible factor signaling could make these two diseases mutually ex-clusive, while excessive reactive oxygen species could enable their coexistence

KLF15 Enables Rapid Switching between Lipogenesis and Gluconeogenesis during Fasting

SummaryHepatic lipogenesis is nutritionally regulated (i.e., downregulated during fasting and upregulated during the postprandial state) as an adaptation to the nutritional environment. While alterations in the expression level of the transcription factor SREBP-1c are known to be critical for nutritionally regulated lipogenesis, upstream mechanisms governing Srebf1 expression remain unclear. Here, we show that the fasting-induced transcription factor KLF15, a key regulator of gluconeogenesis, forms a complex with LXR/RXR, specifically on the Srebf1 promoter. This complex recruits the corepressor RIP140 instead of the coactivator SRC1, resulting in reduced Srebf1 and thus downstream lipogenic enzyme expression during the early and euglycemic period of fasting prior to hypoglycemia and PKA activation. Through this mechanism, KLF15 overexpression specifically ameliorates hypertriglyceridemia without affecting LXR-mediated cholesterol metabolism. These findings reveal a key molecular link between glucose and lipid metabolism and have therapeutic implications for the treatment of hyperlipidemia