Using High Molecular Precision to Study Enzymatically Induced Disassembly of Polymeric Nanocarriers: Direct Enzymatic Activation or Equilibrium-Based Degradation?

Exploiting surface endocytosis receptors using carbohydrate-conjugated nanocarriers brings outstanding approaches to an efficient delivery towards a specific target. Macrophages are cells of innate immunity found throughout the body. Plasticity of macrophages is evidenced by alterations in phenotypic polarization in response to stimuli, and is associated with changes in effector molecules, receptor expression, and cytokine profile. M1-polarized macrophages are involved in pro-inflammatory responses while M2 macrophages are capable of anti-inflammatory response and tissue repair. Modulation of macrophages’ activation state is an effective approach for several disease therapies, mediated by carbohydrate-coated nanocarriers. In this review, polymeric nanocarriers targeting macrophages are described in terms of production methods and conjugation strategies, highlighting the role of mannose receptor in the polarization of macrophages, and targeting approaches for infectious diseases, cancer immunotherapy, and prevention. Translation of this nanomedicine approach still requires further elucidation of the interaction mechanism between nanocarriers and macrophages towards clinical applications.

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An enzymatic activation of formaldehyde for nucleotide methylation

Nature Communications ◽

10.1038/s41467-021-24756-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Charles Bou-Nader ◽

Frederick W. Stull ◽

Ludovic Pecqueur ◽

Philippe Simon ◽

Vincent Guérineau ◽

...

Keyword(s):

Amino Acids ◽

Thymidylate Synthase ◽

Active Site ◽

De Novo ◽

Crystallographic Structure ◽

De Novo Synthesis ◽

Active Site Residues ◽

Enzymatic Activation ◽

Enzyme Cofactors ◽

Unique Ability

AbstractFolate enzyme cofactors and their derivatives have the unique ability to provide a single carbon unit at different oxidation levels for the de novo synthesis of amino-acids, purines, or thymidylate, an essential DNA nucleotide. How these cofactors mediate methylene transfer is not fully settled yet, particularly with regard to how the methylene is transferred to the methylene acceptor. Here, we uncovered that the bacterial thymidylate synthase ThyX, which relies on both folate and flavin for activity, can also use a formaldehyde-shunt to directly synthesize thymidylate. Combining biochemical, spectroscopic and anaerobic crystallographic analyses, we showed that formaldehyde reacts with the reduced flavin coenzyme to form a carbinolamine intermediate used by ThyX for dUMP methylation. The crystallographic structure of this intermediate reveals how ThyX activates formaldehyde and uses it, with the assistance of active site residues, to methylate dUMP. Our results reveal that carbinolamine species promote methylene transfer and suggest that the use of a CH2O-shunt may be relevant in several other important folate-dependent reactions.

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Wound Closure in the Invasive Green AlgaCaulerpa taxifolia by Enzymatic Activation of a Protein Cross-Linker

Angewandte Chemie International Edition ◽

10.1002/anie.200462276 ◽

2005 ◽

Vol 44 (18) ◽

pp. 2806-2808 ◽

Cited By ~ 33

Author(s):

Sven Adolph ◽

Verena Jung ◽

Janine Rattke ◽

Georg Pohnert

Keyword(s):

Wound Closure ◽

Enzymatic Activation ◽

Cross Linker

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Enzymatic activation of hydrazine derivatives. A spin-trapping study.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)33119-3 ◽

1983 ◽

Vol 258 (2) ◽

pp. 796-801 ◽

Cited By ~ 4

Author(s):

B K Sinha

Keyword(s):

Spin Trapping ◽

Hydrazine Derivatives ◽

Enzymatic Activation

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Polymeric Nanocarriers: A Transformation in Doxorubicin Therapies

Materials ◽

10.3390/ma14092135 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2135

Author(s):

Kamila Butowska ◽

Anna Woziwodzka ◽

Agnieszka Borowik ◽

Jacek Piosik

Keyword(s):

Drug Delivery ◽

Wide Spectrum ◽

Stimuli Responsive ◽

First Line ◽

Medical Expenses ◽

Polymeric Nanocarriers ◽

Essential Properties ◽

Life Threatening ◽

History Of ◽

Cancerous Cells

Doxorubicin, a member of the anthracycline family, is a common anticancer agent often used as a first line treatment for the wide spectrum of cancers. Doxorubicin-based chemotherapy, although effective, is associated with serious side effects, such as irreversible cardiotoxicity or nephrotoxicity. Those often life-threatening adverse risks, responsible for the elongation of the patients’ recuperation period and increasing medical expenses, have prompted the need for creating novel and safer drug delivery systems. Among many proposed concepts, polymeric nanocarriers are shown to be a promising approach, allowing for controlled and selective drug delivery, simultaneously enhancing its activity towards cancerous cells and reducing toxic effects on healthy tissues. This article is a chronological examination of the history of the work progress on polymeric nanostructures, designed as efficient doxorubicin nanocarriers, with the emphasis on the main achievements of 2010–2020. Numerous publications have been reviewed to provide an essential summation of the nanopolymer types and their essential properties, mechanisms towards efficient drug delivery, as well as active targeting stimuli-responsive strategies that are currently utilized in the doxorubicin transportation field.

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Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

Polymers ◽

10.3390/polym13071164 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1164

Author(s):

Angeliki Chroni ◽

Thomas Mavromoustakos ◽

Stergios Pispas

Keyword(s):

Molecular Weight ◽

Chain Transfer ◽

Raft Polymerization ◽

Polymeric Nanocarriers ◽

Reversible Addition ◽

2D Noesy ◽

Drug Nanocarriers ◽

Glycol Methyl Ether ◽

Different Molecular Weight

The focus of this study is the development of highly stable losartan potassium (LSR) polymeric nanocarriers. Two novel amphiphilic poly(n-butyl acrylate)-block-poly(oligo(ethylene glycol) methyl ether acrylate) (PnBA-b-POEGA) copolymers with different molecular weight (Mw) of PnBA are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the encapsulation of LSR into both PnBA-b-POEGA micelles. Based on dynamic light scattering (DLS), the PnBA30-b-POEGA70 and PnBA27-b-POEGA73 (where the subscripts denote wt.% composition of the components) copolymers formed micelles of 10 nm and 24 nm in water. The LSR-loaded PnBA-b-POEGA nanocarriers presented increased size and greater mass nanostructures compared to empty micelles, implying the successful loading of LSR into the inner hydrophobic domains. A thorough NMR (nuclear magnetic resonance) characterization of the LSR-loaded PnBA-b-POEGA nanocarriers was conducted. Strong intermolecular interactions between the biphenyl ring and the butyl chain of LSR with the methylene signals of PnBA were evidenced by 2D-NOESY experiments. The highest hydrophobicity of the PnBA27-b-POEGA73 micelles contributed to an efficient encapsulation of LSR into the micelles exhibiting a greater value of %EE compared to PnBA30-b-POEGA70 + 50% LSR nanocarriers. Ultrasound release profiles of LSR signified that a great amount of the encapsulated LSR is strongly attached to both PnBA30-b-POEGA70 and PnBA27-b-POEGA73 micelles.

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Remodeling of Cancer-Specific Metabolism under Hypoxia with Lactate Calcium Salt in Human Colorectal Cancer Cells

Cancers ◽

10.3390/cancers13071518 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1518

Author(s):

Keun-Yeong Jeong ◽

Jae-Jun Sim ◽

Min Hee Park ◽

Hwan Mook Kim

Keyword(s):

Colorectal Cancer ◽

Intracellular Calcium ◽

Cancer Cells ◽

Calcium Salt ◽

Lactate Production ◽

Tca Cycle ◽

Anaerobic Glycolysis ◽

Human Colorectal Cancer ◽

Antitumor Effects ◽

Enzymatic Activation

Hypoxic cancer cells meet their growing energy requirements by upregulating glycolysis, resulting in increased glucose consumption and lactate production. Herein, we used a unique approach to change in anaerobic glycolysis of cancer cells by lactate calcium salt (CaLac). Human colorectal cancer (CRC) cells were used for the study. Intracellular calcium and lactate influx was confirmed following 2.5 mM CaLac treatment. The enzymatic activation of lactate dehydrogenase B (LDHB) and pyruvate dehydrogenase (PDH) through substrate reaction of CaLac was investigated. Changes in the intermediates of the tricarboxylic acid (TCA) cycle were confirmed. The cell viability assay, tube formation, and wound-healing assay were performed as well as the confirmation of the expression of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF). In vivo antitumor effects were evaluated using heterotopic and metastatic xenograft animal models with 20 mg/kg CaLac administration. Intracellular calcium and lactate levels were increased following CaLac treatment in CRC cells under hypoxia. Then, enzymatic activation of LDHB and PDH were increased. Upon PDH knockdown, α-ketoglutarate levels were similar between CaLac-treated and untreated cells, indicating that TCA cycle restoration was dependent on CaLac-mediated LDHB and PDH reactivation. CaLac-mediated remodeling of cancer-specific anaerobic glycolysis induced destabilization of HIF-1α and a decrease in VEGF expression, leading to the inhibition of the migration of CRC cells. The significant inhibition of CRC growth and liver metastasis by CaLac administration was confirmed. Our study highlights the potential utility of CaLac supplementation in CRC patients who display reduced therapeutic responses to conventional modes owing to the hypoxic tumor microenvironment.

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