Progress 07/01/24 to 06/30/25

Outputs
Target Audience:Consumers, particularly people with high intake of refined carbohydrates and sweet sugar beverages may benefit from the protective effects of increased consumption of tomatoes and tomato products rich in phytoene and from the knowledge that phytoene is a key biologically active food-derived component against nonalcoholic fatty liver disease. Phytoene is a precursor of major carotenoids in plants. Farmers of these vegetables and fruits rich in phytoene will benefit commercially and economically as well. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project utilizing animal models, biochemistry and molecular biology, and omics techiques provided a strong training enviroment for one Ph.D. student and two master studentsof Tufts University School of Nutrition. How have the results been disseminated to communities of interest?We have reported our research finding at the following meetings: Wang XD. Oral presentation on "Dietary tomato carotenoids on gut-liver axis" NIFA/AFRI Project Director meeting, 06/2025 Lee, NY and Wang, XD. Oral presentation on "Feeding phytoene, an upstream plant precursor of lycopene in tomatoes, attenuated nonalcoholic fatty liver disease in mice" in the American Socity of Nutrition annual meeting, 05/2025 What do you plan to do during the next reporting period to accomplish the goals?We will continue to determine if age (8 months vs. 24 months) and carotenoid cleavage enzymes (BCO1/BCO2) differentially modulate HRCD-induced NAFLD development through altering the SIRT1 signaling, gut microbiome, gut-liver axis, and systemic metabolomic profiles. We will further to determine whether tomato powder and phytoene elicits protection against NAFLD through modulating the gut microbiome and plasma metabolomic profiles. We will 1) to carry out gut microbial profiles analysis using fecal samples and examine intestinal barrier function by altering structure and localization of tight junctions; 2) examine whether increased SIRT1 activity by phytoene suppresses biomarkers of lipolysis in mesenteric adipose tissue and free fatty acid since we have showed that the loss of SIRT1 activity induces NAFLD by enhancing lipolysis and mobilizing free fatty acids to the liver from mesenteric adipose tissue; 3) to examine plasma metabolomics for targeted metabolic profiling (e.g., perturbations of lipid metabolism and bile-acid synthesis); and 4) to identify differentially expressed genes associated with SIRT1 pathway activation using RNA-seq analysis.

Impacts
What was accomplished under these goals? Colorless phytoene, a precursor of major carotenoids and lycopene abundant in tomatoes, has received comparatively little attention despite its bioavailability. We investigated whether dietary phytoenecontributes to protective effects against high-refined carbohydrate diet-induced nonalcoholic fatty liver disease (NAFLD) in mice, and whether its effects depend on carotenoid cleavage enzymes (BCO1 and BCO2).We found that phytoene feeding (equivalent to 2-3 medium-sized tomatoes per day in humans)resulted significant accumulation of phytoene in both plasma and liver tissue of mice. Interestingly, phytoene feeding, similar to tomato powder feeding, significantly reduced HRCD-induced hepatic steatosis scores and hepatic triglyceride levels compared to HRCD-fed alone controls. These protective effects were associated with increased hepatic mRNA and protein expression of the deacetylase sirtuin 1; increased hepatic AMPK phosphorylation and acetyl-CoA carboxylase phosphorylation; and upregulated hepatic mRNA expression of mitochondrial fatty acid oxidation genes.Our finding provided a strong experimental evidence that lycopene alone is not solely responsible for the health benefits of tomato consumption against NAFLD, but may instead be independently related to phytoene in tomatoes. The protective effects of phytoene may involve the up-regulation of sirtuin 1 and the enhancement of mitochondrial fatty acid oxidation through the AMPK-ACC axis. We further evaluated the protective effects of phytoene feeding against HRCD-induced NAFLD development in the absence of carotenoid cleavage enzymes (BCO1/BCO2) in mice. We found that the phytoene feeding resulted significant higher accumulation of phytoene, but there was no protective effect of phytoene feeding against NAFLD in the liver of micelacking BCO1/BCO2, as compared with that of wildtype mice. These data indicate that phytoene can be cleaved/metabolized by BCO1/BCO2 in vivo, and the observed protective effect of phytoene could be related to BCO1/BCO2 cleavage metabolites of phytoene, rather than its intact form.

Publications

Progress 07/01/23 to 06/30/24

Outputs
Target Audience:Researchers in the field of fatty liver disease prevention and consumers, particularly people with obesity, will benefit from the healthy benifits of tomatoes and tomato products, and from knowledge of tomato carotenoids as dietary biological active components. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The projet has provided a training enviroment for PHD students of Tufts School of Nutrition. The project utilizing biochemistry and molecular biology techniques assisted onegraduate student to working on herPHD thesis research and twomaster students for their lab pratictum projects. How have the results been disseminated to communities of interest?We have reported our finding at the following meetings: Wang XD. Oral presentation on "Dietary Tomato Powder Feeding Attenuated Non-Alcoholic Fatty Liver Disease" NIFA/AFRI project director meeting, Indiana, 05/2024 Wang XD. Invited speaker on "Role of sirtuin 1 and heathy benefits of carotenoids against age-related diseases" in the American Society of Nutrition (ASN) annual meeting, Chicago, IL 06/2024 Lee N, Cheng J, and Wang XD. Poster presentation on "Dietary Tomato Powder Feeding Attenuated Non-Alcoholic Fatty Liver Disease Independent of Sirtuin 1 Activity in Mice" in the ASN annual meeting, Chicago, IL 06/2024 What do you plan to do during the next reporting period to accomplish the goals?We will contuine to explore whether age and carotenoid cleavage enzymes may differentially contribute to nonalcoholic fatty liver disease development and whether tomato powder and key tomato-based carotenoids (such as phytoene) elicit protection against nonalcoholic fatty liver disease through modulating the senescent cells, gut microbiome, metabolic endotoxemia, and systemic plasma metabolomic profiles.

Impacts
What was accomplished under these goals? Weexamined whether dietary tomato powder feeding as a whole food preventsnonalcoholic fliver disease (NAFLD)dependent on sirtuin 1 (SIRT1), which is a highly conserved NAD+-dependent protein deacetylase that modulates lipid metabolism, oxidative stress, inflammation and lifespan.We found that tomato powder feeding (equivalent to dietary lycopene intake of 8.1 mg or 2-3 median size of raw tomatoes (~300 g wet weight) per day in humans) significantly reduced plasma levels of triglycerides, hepatic steatosis score, and inflammatory foci in both wild type mice and mutation mice with ablated sirt1 activity at comparable hepatic lycopene concentrations. Interestingly, in the absence of sirt1 activity, tomato powder feeding still decreased hepatic levels of oxidative stress biomarkers, and lowered the mRNA expression of IL-6 in mesenteric adipose tissue and the protein concentration of IL-6 in both plasma and the liver. We concluded that dietary tomato feeding, independent of SIRT1 activity, ameliorates HFD-induced NAFLD, oxidative stress and inflammatory responses in the liver and mesenteric adipose tissue.

Publications