Rationale: Dysregulation of cellular metabolism has been shown to participate in several pathologic processes. However, the role of metabolic reprogramming is not well appreciated in the pathogenesis of organ fibrosis.Objectives: To determine if glycolytic reprogramming participates in the pathogenesis of lung fibrosis and assess the therapeutic potential of glycolytic inhibition in treating lung fibrosis.Methods: A cell metabolism assay was performed to determine glycolytic flux and mitochondrial respiration. Lactate levels were measured to assess glycolysis in fibroblasts and lungs. Glycolytic inhibition by genetic and pharmacologic approaches was used to demonstrate the critical role of glycolysis in lung fibrosis.Measurements and Main Results: Augmentation of glycolysis is an early and sustained event during myofibroblast differentiation, which is dependent on the increased expression of critical glycolytic enzymes, in particular, 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3). Augmented glycolysis contributes to the stabilization of hypoxia-inducible factor 1-a, a master regulator of glycolytic enzymes implicated in organ fibrosis, by increasing cellular levels of tricarboxylic acid cycle intermediate succinate in lung myofibroblasts. Inhibition of glycolysis by the PFKFB3 inhibitor 3PO or genomic disruption of the PFKFB3 gene blunted the differentiation of lung fibroblasts into myofibroblasts, and attenuated profibrotic phenotypes in myofibroblasts isolated from the lungs of patients with idiopathic pulmonary fibrosis. Inhibition of glycolysis by 3PO demonstrates therapeutic benefit in bleomycin-induced and transforming growth factor-b1-induced lung fibrosis in mice.Conclusions: Our data support the novel concept of glycolytic reprogramming in the pathogenesis of lung fibrosis and provide proof-of-concept that targeting this pathway may be efficacious in treating fibrotic disorders, such as idiopathic pulmonary fibrosis.
Each major step leading to the classical yellow, orange and red constituents of Monascus azaphilone pigments was defined.
Nicotinamide adenine dinucleotide (NAD+) and its metabolites function as critical regulators to maintain physiologic processes, enabling the plastic cells to adapt to environmental changes including nutrient perturbation, genotoxic factors, circadian disorder, infection, inflammation and xenobiotics. These effects are mainly achieved by the driving effect of NAD+ on metabolic pathways as enzyme cofactors transferring hydrogen in oxidation-reduction reactions. Besides, multiple NAD+-dependent enzymes are involved in physiology either by post-synthesis chemical modification of DNA, RNA and proteins, or releasing second messenger cyclic ADP-ribose (cADPR) and NAADP+. Prolonged disequilibrium of NAD+ metabolism disturbs the physiological functions, resulting in diseases including metabolic diseases, cancer, aging and neurodegeneration disorder. In this review, we summarize recent advances in our understanding of the molecular mechanisms of NAD+-regulated physiological responses to stresses, the contribution of NAD+ deficiency to various diseases via manipulating cellular communication networks and the potential new avenues for therapeutic intervention.
Ever present hurdles for the discovery of new drugs for cancer therapy have necessitated the development of the alternative strategy of drug repurposing, the development of old drugs for new therapeutic purposes. This strategy with a cost-effective way offers a rare opportunity for the treatment of human neoplastic disease, facilitating rapid clinical translation. With an increased understanding of the hallmarks of cancer and the development of various data-driven approaches, drug repurposing further promotes the holistic productivity of drug discovery and reasonably focuses on target-defined antineoplastic compounds. The "treasure trove" of non-oncology drugs should not be ignored since they could target not only known but also hitherto unknown vulnerabilities of cancer. Indeed, different from targeted drugs, these old generic drugs, usually used in a multi-target strategy may bring benefit to patients. In this review, aiming to demonstrate the full potential of drug repurposing, we present various promising repurposed non-oncology drugs for clinical cancer management and classify these candidates into their proposed administration for either mono-or drug combination therapy. We also summarize approaches used for drug repurposing and discuss the main barriers to its uptake.
The M1 and M2 polarized phenotypes dictate distinctive roles for macrophages as they participate in inflammatory disorders. There has been growing interest in the role of cellular metabolism in macrophage polarization. However, it is currently unclear if different aspects of a specific metabolic program coordinately regulate this cellular process. In this study, we found that pyruvate dehydrogenate kinase 1 (PDK1), a key regulatory enzyme in glucose metabolism, plays an important role in the differential activation of macrophages. Knockdown of PDK1 diminished M1, whereas it enhanced M2 activation of macrophages. Mechanistically, PDK1 knockdown led to diminished aerobic glycolysis in M1 macrophages, which likely accounts for the attenuated inflammatory response in these cells. Furthermore, we found that mitochondrial respiration is enhanced during and required by the early activation of M2 macrophages. Suppression of glucose oxidation, but not that of fatty acids, inhibits this process. Consistent with its inhibitory role in early M2 activation, knockdown of PDK1 enhanced mitochondrial respiration in macrophages. Our data suggest that two arms of the glucose metabolism synergistically regulate the differential activation of macrophages. Our findings also highlight the central role of PDK1 in this event via controlling glycolysis and glucose oxidation.
Macrophages demonstrate a high level of plasticity, with the ability to undergo dynamic transition between M1 and M2 polarized phenotypes. The role of miRNAs in regulating macrophage polarization has been largely undefined. In this study, we found that microRNA let-7c is expressed at a higher level in M-BMM (M2 macrophages) than in GM-BMM (M1 macrophages). let-7c levels are also greater in alveolar macrophages from fibrotic lungs as compared to those from normal lungs. let-7c expression was decreased when M-BMM converted to GM-BMM whereas increased when GM-BMM converted to M-BMM. LPS stimulation reduced let-7c expression in M-BMM. We found that overexpression of let-7c in GM-BMM diminished M1 phenotype expression while promoting polarization to the M2 phenotype. In contrast, knockdown of let-7c in M-BMM promoted M1 polarization, and diminished M2 phenotype expression. We found that let-7c targets C/EBP-δ, a transcriptional factor that plays an important role in inflammatory response. Furthermore, we found that let-7c regulates bactericidal and phagocytic activities of macrophages, two functional phenotypes implicated in macrophage polarization. Our data suggest that the microRNA let-7c plays an important role in regulating macrophage polarization.
Breast cancer is the most common cancer among women worldwide, yet successful treatment remains a clinical challenge. Ivermectin, a broad-spectrum antiparasitic drug, has recently been characterized as a potential anticancer agent due to observed antitumor effects. However, the molecular mechanisms involved remain poorly understood. Here, we report a role for ivermectin in breast cancer suppression by activating cytostatic autophagy both in vitro and in vivo. Mechanistically, ivermectin-induced autophagy in breast cancer cells is associated with decreased P21-activated kinase 1 (PAK1) expression via the ubiquitinationmediated degradation pathway. The inhibition of PAK1 decreases the phosphorylation level of Akt, resulting in the blockade of the Akt/mTOR signaling pathway. In breast cancer xenografts, the ivermectin-induced cytostatic autophagy leads to suppression of tumor growth. Together, our results provide a molecular basis for the use of ivermectin to inhibit the proliferation of breast cancer cells and indicate that ivermectin is a potential option for the treatment of breast cancer. Cancer Res; 76(15); 4457-69. Ó2016 AACR.
Background:The role of miRNAs in macrophage polarization has not been well defined. Results: miR-125a-5p promotes M2, while it suppresses M1 macrophage polarization. Conclusion: miR-125a-5p is an important regulator of the differential activation of macrophages. Significance: Delineation of the role of miR-125a-5p in macrophage polarization provides insights into miRNA regulation of inflammation, tissue repair and tumor progression.
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