Johanna DiStefano

Johanna DiStefano Ph.D.

Metabolic and Fibrotic Disease Program

Diabetes and Fibrotic Disease Unit 

Johanna DiStefano Ph.D.

Dr. Johanna DiStefano is a Professor and Head of the Diabetes and Fibrotic Disease Unit where she leads research in the molecular mechanisms of chronic, progressive metabolic diseases.

For more than twenty years, Dr. DiStefano has investigated molecular mechanisms underlying type 2 diabetes and related hepatic and renal complications. During this time, she has led many successful NIH-funded studies to identify genetic and molecular factors associated with the development and progression of diabetic kidney disease, nonalcoholic fatty liver disease (NAFLD), and diabetic dyslipidemia, all of which contribute significantly to morbidity and mortality in patients with diabetes. She currently has major efforts in the investigation of epigenetic mechanisms underlying the development and progression of NAFLD and the role of extracellular vesicle content in mediating metabolic derangements in obesity and improvements in metabolic parameters associated with bariatric surgery and lifestyle interventions. Her team works with ethnically diverse patient populations using state-of-the-art laboratory approaches, including high throughput sequencing of DNA, RNA, and noncoding RNA, in vitro model systems, functional genomics, extracellular vesicle profiling, and global DNA methylation analysis, to address important gaps in our understanding of disease pathogenesis and directly impact unmet clinical needs. The longstanding goal of her scientific program has been to conduct research leading to 1) an enhanced mechanistic understanding of complex disease processes, 2) early and noninvasive diagnostic assays to identify at-risk individuals for preventative strategies, 3) individualized treatment strategies in the clinical management of disease, and 4) identification of targets for the development of new and improved therapeutics.

Dr. DiStefano has published over 100 scientific articles and book chapters related to the molecular analysis of complex metabolic diseases. She has been a standing member of the Kidney, Nutrition, Obesity, and Diabetes (KNOD) study section of the National Institutes of Health and regularly participates in ad hoc grant review committees. Dr. DiStefano has mentored over 50 undergraduate and graduate students, post-doctoral fellows, and junior faculty, and has served on a number of steering committees and multi-centered consortia. In addition, she holds an Affiliate Faculty position in the College of Nursing at Arizona State University. She has also been a member of the Family Investigation in Nephropathy and Diabetes (FIND) study, adjunct faculty in the School of Life Sciences at Arizona State University, a consultant to the Charles R. Drew University of Medicine and Science-NIH/NIDDK High School Summer Research Program, and a Visiting Professor in the Department of Internal Medicine at Catholic University in Rome, Italy. She earned a B.S. in Chemistry and Psychology from The Ohio State University and a Ph.D. in Molecular Biology and Biochemistry from Kent State University. She completed a post-doctoral fellowship in genetic studies of diabetes in Native Americans at the NIDDK, where she served as a Staff Fellow prior to joining the faculty at TGen in 2003.


Differentially expressed mRNAs and lncRNAs shared between activated human hepatic stellate cells and NASH fibrosis.  Gerhard GS, Davis B, Wu X, Hanson A, Wilhelmsen D, Piras IS, Still CD, Chu X, Petrick AT, DiStefano JK. 2020. Biochem Biophys Rep. 22: 100753.

Fructose-mediated Effects on Gene Expression and Epigenetic Mechanisms Associated with NAFLD Pathogenesis. DiStefano JK. 2019. Cell Mol Life Sci. 77 (11): 2079-2090.

AEBP1 expression increases with severity of fibrosis in NASH and is regulated by glucose, palmitate, and miR-372-3p.  Gerhard GS, Hanson A, Wilhelmsen D, Piras IS, Still CD, Chu X, Petrick AT, DiStefano JK. 2019. PLOS ONE. 14(7): e0219764.

Chemokine ligand 20 (CCL20) expression increases with NAFLD stage and hepatic stellate cell activation.   Hanson A, Piras IS, Wilhelmsen D, Still CD, Chu X, Petrick AT, Gerhard GS, DiStefano JK. 2019. Cytokine. 123:154789.

Differentially methylated loci in NAFLD cirrhosis are associated with key signaling pathways.  Gerhard GS, Malenica I, Llaci L, Chu X, Petrick A, Still CD, DiStefano JK. 2018. Clin Epigenetics 10(1): 93-102.

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