shikonin and Inflammatory-Bowel-Diseases

Pyruvate kinase M2 is a critical enzyme that regulates cell metabolism and growth under different physiological conditions. In its metabolic role, pyruvate kinase M2 catalyzes the last glycolytic step which converts phosphoenolpyruvate to pyruvate with the generation of ATP. Beyond this metabolic role in glycolysis, PKM2 regulates gene expression in the nucleus, phosphorylates several essential proteins that regulate major cell signaling pathways, and contribute to the redox homeostasis of cancer cells. The expression of PKM2 has been demonstrated to be significantly elevated in several types of cancer, and the overall inflammatory response. The unusual pattern of PKM2 expression inspired scientists to investigate the unrevealed functions of PKM2 and the therapeutic potential of targeting PKM2 in cancer and other disorders. Therefore, the purpose of this review is to discuss the mechanistic and therapeutic potential of targeting PKM2 with the focus on cancer metabolism, redox homeostasis, inflammation, and metabolic disorders. This review highlights and provides insight into the metabolic and non-metabolic functions of PKM2 and its relevant association with health and disease.

Topics: Adenosine Triphosphate; Atherosclerosis; Carrier Proteins; Cell Proliferation; Enzyme Inhibitors; Gene Expression Regulation, Enzymologic; Glycolysis; Homeostasis; Humans; Inflammation; Inflammatory Bowel Diseases; Insulin; Kidney Diseases; Liver; Membrane Proteins; Metabolic Diseases; Naphthoquinones; Neoplasm Metastasis; Neoplasms; Neuralgia; Oxidants; Oxidation-Reduction; Protein Isoforms; Sepsis; Signal Transduction; Thyroid Hormone-Binding Proteins; Thyroid Hormones; Tissue Distribution

Shikonin is a natural product with antioxidant and anti-inflammatory activities. The biological activity of shikonin is still not fully understood, as well as its association with innate immunity and immune and inflammatory bowel disease (IBD) in humans. In this study, the toxicity of shikonin on Raw264.7 cells was assayed by MTT, and polarization of inflammatory macrophages was determined by flow cytometry. The results showed that shikonin can inhibit the polarization of macrophages towards M1 type and significantly inhibited the production of NO in the concentration range of 0.5-1 μM. In addition, after treatment with shikonin, the production of IL-1β and TNF-α was significantly decreased. After shikonin administration, the body weight loss and decrease of colon length were significantly suppressed in DSS-treated colitis C57BL/6 mice. The pro-inflammatory cytokines TNF-α and IL-1β in colonic homogenate were significantly decreased. Shikonin treatment resulted in a notable improvement in the histopathological manifestations in DSS-treated animals at 25/50 mg/kg. Meanwhile, we found that shikonin can regulate differentiation of T helper 17 cell (Th17)/regulatory T cell (Treg), thereby regulating the balance of Th17/Treg cells and exerting an anti-inflammatory effect in IBD animal models. In conclusion, we found that shikonin protects against DSS-induced acute colitis by, among other things, reducing immune cell infiltration, polarizing macrophages, and regulating Th17/Treg differentiation, as well as by downregulating the release of inflammatory cytokines. These findings showed that shikonin can improve inflammation by affecting macrophage polarization. Our experimental data provide experimental evidence and theory basis for research on anti-inflammatory effects for the shikonin as health or functional food.

Topics: Animals; Colitis; Colon; Cytokines; Disease Models, Animal; Humans; Inflammatory Bowel Diseases; Mice; Mice, Inbred C57BL; Tumor Necrosis Factor-alpha

Topics: Animals; Chitosan; Colitis; Colon; Cytokines; Hydrogen-Ion Concentration; Inflammatory Bowel Diseases; Mice; Nanoparticles