Type 2 diabetes (T2D) has reached an epidemic level globally. Most current treatments ameliorate the hyperglycemic symptom but are not effective in correcting the underlying cause. One important causal factor of T2D is ectopic accumulation of lipid in organs such as liver and muscle. Mitochondrial uncoupling, which reduces cellular energy efficiency and increases lipid oxidation, represents an appealing therapeutic strategy. The challenge, however, is to discover safe mitochondrial uncouplers for practical use. Niclosamide is an FDA approved anthelmintic drug that uncouples mitochondria of parasitic worms. Here we show that niclosamide ethanolamine salt (NEN) uncouples mammalian mitochondria at upper nanomolar concentrations. Oral NEN increases energy expenditure and lipid metabolism in mice. It is efficacious in preventing and treating high-fat diet (HFD) induced hepatic steatosis and insulin resistance. Moreover, it improves glycemic control and delays disease progression of the db/db mice. Given the well- documented safety profile of NEN, our study provides a potentially practical pharmacological embodiment of a new strategy for treating T2D.

Metabolism of cancer cells is characterized by aerobic glycolysis, or the Warburg effect. Aerobic glycolysis reduces pyruvate flux into mitochondria, preventing a complete oxidation of glucose and shunting glucose to anabolic pathways essential for cell proliferation. Here we tested a new strategy, mitochondrial uncoupling, for its potential of antagonizing the anabolic effect of aerobic glycolysis and for its potential anticancer activities. Mitochondrial uncoupling is a process that facilitates proton influx across the mitochondrial inner membrane without generating ATP, stimulating a futile cycle of acetyl- CoA oxidation. We tested two safe mitochondrial uncouplers, NEN (niclosamide ethanolamine) and oxyclozanide, on their metabolic effects and anti-cancer activities. We used metabolomic NMR to examine the effect of mitochondrial uncoupling on glucose metabolism in colon cancer MC38 cells. We further tested the anti-cancer effect of NEN and oxyclozanide in cultured cell models, APCmin/+ mouse model, and a metastatic colon cancer mouse model. Using a metabolomic NMR approach, we demonstrated that mitochondrial uncoupling promotes pyruvate influx to mitochondria and reduces various anabolic pathway activities. Moreover, mitochondrial uncoupling inhibits cell proliferation and reduces clonogenicity of cultured colon cancer cells. Furthermore, oral treatment with mitochondrial uncouplers reduces intestinal polyp formation in APCmin/+ mice, and diminishes hepatic metastasis of colon cancer cells transplanted intrasplenically. Our data highlight a unique approach for targeting cancer cell metabolism for cancer prevention and treatment, identified two prototype compounds, and shed light on the anti-cancer mechanism of niclosamide.

Chenpi is the dry peel of the plant Citrus reticulata Blanco after an aging processing. It has been used as an antidigestive and anti-inflammatory traditional medicine, as well as culinary seasoning and dietary supplement, in China. However, its efficacy and underlying scientific mechanism have not been sufficiently investigated. Chenpi is uniquely enriched with a high content of 5-demethylated polymethoxyflavones (5-OH PMFs). The effect of chenpi extract on improving metabolic features was examined using high-fat diet (HFD)-induced obesity/diabetes mouse model. Oral administration of 0.25 and 0.5% chenpi extract in food over 15 weeks markedly prevented HFD-induced obesity, hepatic steatosis, and diabetic symptoms. The beneficial effect is associated with 5'-adenosine monophosphate-activated protein kinase (AMPK) activation in adipose tissue. Our results indicate that 5-OH PMFs-enriched chenpi extract is effective in preventing obesity and type 2 diabetes, and its effect might be related to improvement in lipid metabolism associated with activation of the AMPK pathway.