RESUMO
Epidemiological and animal studies indicate that pre-existing diabetes increases the risk of Parkinson's disease(PD).However,the mechanisms underlying this association remain unclear.In the present study,we found that high glucose(HG)levels in the cerebrospinal fluid(CSF)of diabetic rats might enhance the effect of a subthreshold dose of the neurotoxin 6-hydroxydopamine(6-OHDA)on the development of motor disorders,and the damage to the nigrostriatal dopaminergic neuronal pathway.In vitro,HG promoted the 6-OHDA-induced apoptosis in PC12 cells differentiated to neurons with nerve growth factor(NGF)(NGF-PC12).Metabolomics showed that HG promoted hyperglycolysis in neurons and impaired tricarboxylic acid cycle(TCA cycle)activity,which was closely related to abnormal mito-chondrial fusion,thus resulting in mitochondrial loss.Interestingly,HG-induced upregulation of pyruvate kinase M2(PKM2)combined with 6-OHDA exposure not only mediated glycolysis but also promoted abnormal mitochondrial fusion by upregulating the expression of MFN2 in NGF-PC12 cells.In addition,we found that PKM2 knockdown rescued the abnormal mitochondrial fusion and cell apoptosis induced by HG+6-OHDA.Furthermore,we found that shikonin(SK),an inhibitor of PKM2,restored the mito-chondrial number,promoted TCA cycle activity,reversed hyperglycolysis,enhanced the tolerance of cultured neurons to 6-OHDA,and reduced the risk of PD in diabetic rats.Overall,our results indicate that diabetes promotes hyperglycolysis and abnormal mitochondrial fusion in neurons through the upre-gulation of PKM2,leading to an increase in the vulnerability of dopaminergic neurons to 6-OHDA.Thus,the inhibition of PKM2 and restoration of mitochondrial metabolic homeostasis/pathways may prevent the occurrence and development of diabetic PD.
RESUMO
As a powerful tool to advance drug discovery, molecular imaging may provide new insights into the process of drug effect and therapy at cellular and molecular levels. When compared with other detection methods, fluorescence-based strategies are highly attractive and can be used to illuminate pathways of drugs' transport, with multi-color capacity, high specificity and good sensitivity. The conjugates of fluorescent molecules and therapeutic agents create exciting avenues for real-time monitoring of drug delivery and distribution, both in vitro and in vivo. In this short review, we discuss recent developments of small molecule-based fluorophore-drug conjugates, including non-cleavable and cleavable ones, that are capable of visualizing drug delivery.
RESUMO
Therapeutic monoclonal antibodies have become one of the central components of the healthcare system and continuous efforts are made to bring innovative antibody therapeutics to patients in need. It is equally critical to acquire sufficient knowledge of their molecular structure and biological functions to ensure the efficacy and safety by incorporating new detection approaches since new challenges like individual differences and resistance are presented. Conventional techniques for determining antibody disposition including plasma drug concentration measurements using LC-MS or ELISA, and tissue dis-tribution using immunohistochemistry and immunofluorescence are now complemented with molecular imaging modalities like positron emission tomography and near-infrared fluorescence imaging to obtain more dynamic information, while methods for characterization of antibody's interaction with the target antigen as well as visualization of its cellular and intercellular behavior are still under development. Recent progress in detecting therapeutic antibodies, in particular, the development of methods suitable for illustrating the molecular dynamics, is described here.
