Charles E. Schmidt College of Medicine
Florida Atlantic University
777 Glades Road
Boca Raton, FL 33431
Yoshimi Shibata received his Ph.D. degree from Tohoku University School of Medicine, Sendai, Japan. Under the supervision of mentor Dr. Nakao Ishida, his doctoral research focused on characterizing a systemic effect of local macrophages producing an acute phase protein in pro-cancer development. His postdoctoral training was conducted in the laboratory of Dr. Alvin Volkman at East Carolina University School of Medicine in Greenville, NC. Dr. Shibata’s post-doctoral research was to establish novel experimental approaches dissecting roles of heterogeneous macrophage populations that are activated under chronic inflammatory conditions relevant to tuberculosis, cancer and sarcoidosis.
To further understand inflammatory roles of heterogeneous macrophage populations, Dr. Shibata’s lab at FAU has developed a method to prepare non-toxic particles of chitin, purified from crab shells. Chitin is a natural N-acetyl glucosamine polymer and exists in fungi, parasites, insects and crustaceans, but not in mammals. Current research in his group focuses on chitin particles in order to understand roles of chitin in host responses to chitin-containing pathogens and allergens. A wide range of polarized macrophage activations by chitin particles, seemingly dependent on their particle sizes, has been proposed. For instance, phagocytosis of chitin microparticles (1 – 10 µm diameters) induces classically activated macrophages (M1), capable of killing intracellular microbes but also damaging near-by tissues. In contrast, large chitin beads (40 – 70 µm), which are larger than macrophages and difficult to be phagocytosed, tend to induce alternatively activated macrophages (M2), which repair tissue damage but enhance allergic responses.
The phenotypes of M1 and M2 activated by chitin addressed above are commonly seen in chronic inflammatory diseases, such as mycobacterial infections, atherosclerosis, asthma, and cancer. To understand inflammatory roles of macrophages, Dr. Shibata’s lab specifically studies a mechanism of a shift of M1-to-M2 activation, regulating the fate of inflammation. The chronic inflammatory diseases appear to be due to an incomplete shift of M1-to-M2 (less magnitude and/or delayed timing). Therefore, we seek molecular events during the M1-to-M2 shift and determine whether applications of selected chitin particles above restore the shift in an appropriate manner, beneficial as novel anti-inflammatory treatments. In addition, we are evaluating whether dietary chitin particles induce gut probiosis, an additional aspect of anti-inflammatory effects on inflammatory bowel disease (IBD), asthma, autoimmune diseases, obesity and cancer. Interestingly, the anti-IBD effect of dietary chitin particles seems to be dependent on sex and GI enzymes digesting chitin.
Dr. Shibata is also dedicated to education and training. He led the medical research education program at FAU, training high school students and undergraduate students in summers, as well as DIS, MS and Ph.D. students and post-doctoral fellows, to enjoy daily research activities and explore potential breakthrough in medical biology.