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Scientific Reports Aug 2022The intracellular microsporidian parasite Nosema ceranae is known to compromise bee health by induction of energetic stress and downregulation of the immune system....
The intracellular microsporidian parasite Nosema ceranae is known to compromise bee health by induction of energetic stress and downregulation of the immune system. Porphyrins are candidate therapeutic agents for controlling Nosema infection without adverse effects on honeybees. In the present work, the impact of two protoporphyrin IX derivatives, i.e. PP[Asp] and PP[Lys], on Apis mellifera humoral immune response has been investigated in laboratory conditions in non-infected and N. ceranae-infected honeybees. Fluorescence spectroscopy analysis of hemolymph showed for the first time that porphyrin molecules penetrate into the hemocoel of honeybees. Phenoloxidase (PO) activity and the expression of genes encoding antimicrobial peptides (AMPs: abaecin, defensin, and hymenoptaecin) were assessed. Porphyrins significantly increased the phenoloxidase activity in healthy honeybees but did not increase the expression of AMP genes. Compared with the control bees, the hemolymph of non-infected bees treated with porphyrins had an 11.3- and 6.1-fold higher level of PO activity after the 24- and 48-h porphyrin administration, respectively. Notably, there was a significant inverse correlation between the PO activity and the AMP gene expression level (r = - 0.61696, p = 0.0143). The PO activity profile in the infected bees was completely opposite to that in the healthy bees (r = - 0.5118, p = 0.000), which was related to the changing load of N. ceranae spores in the porphyrin treated-bees. On day 12 post-infection, the spore loads in the infected porphyrin-fed individuals significantly decreased by 74%, compared with the control bees. Our findings show involvement of the honeybee immune system in the porphyrin-based control of Nosema infection. This allows the infected bees to improve their lifespan considerably by choosing an optimal PO activity/AMP expression variant to cope with the varying level of N. ceranae infection.
Topics: Animals; Amides; Bees; Immunity; Monophenol Monooxygenase; Nosema; Protoporphyrins
PubMed: 36002552
DOI: 10.1038/s41598-022-18534-9 -
Biochimica Et Biophysica Acta. Proteins... Jan 2021There is a high functional diversity within the structural superfamily of porphyrin-binding dimeric α + β barrel proteins. In this review we aim to analyze... (Review)
Review
There is a high functional diversity within the structural superfamily of porphyrin-binding dimeric α + β barrel proteins. In this review we aim to analyze structural constraints of chlorite dismutases, dye-decolorizing peroxidases and coproheme decarboxylases in detail. We identify regions of structural variations within the highly conserved fold, which are most likely crucial for functional specificities. The loop linking the two ferredoxin-like domains within one subunit can be of different sequence lengths and can adopt various structural conformations, consequently defining the shape of the substrate channels and the respective active site architectures. The redox cofactor, heme b or coproheme, is oriented differently in either of the analyzed enzymes. By thoroughly dissecting available structures and discussing all available results in the context of the respective functional mechanisms of each of these redox-active enzymes, we highlight unsolved mechanistic questions in order to spark future research in this field.
Topics: Bacteria; Bacterial Proteins; Carboxy-Lyases; Catalytic Domain; Conserved Sequence; Ferredoxins; Heme; Models, Molecular; Oxidation-Reduction; Oxidoreductases; Peroxidases; Porphyrins; Protein Binding; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand; Protein Interaction Domains and Motifs; Protein Multimerization; Water Decolorization
PubMed: 32891739
DOI: 10.1016/j.bbapap.2020.140536 -
Nature Communications Jun 2022Photoremovable protecting groups (PPGs) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical...
Photoremovable protecting groups (PPGs) represent one of the main contemporary implementations of photochemistry in diverse fields of research and practical applications. For the past half century, organic and metal-complex PPGs were considered mutually exclusive classes, each of which provided unique sets of physical and chemical properties thanks to their distinctive structures. Here, we introduce the meso-methylporphyrin group as a prototype hybrid-class PPG that unites traditionally exclusive elements of organic and metal-complex PPGs within a single structure. We show that the porphyrin scaffold allows extensive modularity by functional separation of the metal-binding chromophore and up to four sites of leaving group release. The insertion of metal ions can be used to tune their spectroscopic, photochemical, and biological properties. We provide a detailed description of the photoreaction mechanism studied by steady-state and transient absorption spectroscopies and quantum-chemical calculations. Our approach applied herein could facilitate access to a hitherto untapped chemical space of potential PPG scaffolds.
Topics: Ions; Light; Metals; Photochemistry; Porphyrins
PubMed: 35750661
DOI: 10.1038/s41467-022-31288-2 -
Protein Science : a Publication of the... Dec 2020Human ATP-binding cassette transporter 6 of subfamily B (ABCB6) is an ABC transporter involved in the translocation toxic metals and anti-cancer drugs. Using...
Human ATP-binding cassette transporter 6 of subfamily B (ABCB6) is an ABC transporter involved in the translocation toxic metals and anti-cancer drugs. Using cryo-electron microscopy, we determined the molecular structure of full-length ABCB6 in an apo state. The structure of ABCB6 unravels the architecture of a full-length ABCB transporter that harbors two N-terminal transmembrane domains which is indispensable for its ATPase activity in our in vitro assay. A slit-like substrate binding pocket of ABCB6 may accommodate the planar shape of porphyrins, and the existence of a secondary cavity near the mitochondrial intermembrane space side would further facilitate substrate release. Furthermore, the ATPase activity of ABCB6 stimulated with a variety of porphyrin substrates showed different profiles in the presence of glutathione (GSH), suggesting the action of a distinct substrate translocation mechanism depending on the use of GSH as a cofactor.
Topics: ATP-Binding Cassette Transporters; Cryoelectron Microscopy; Glutathione; HEK293 Cells; Humans; Porphyrins; Protein Domains
PubMed: 33007128
DOI: 10.1002/pro.3960 -
Angewandte Chemie (International Ed. in... Aug 2022Multifunctional porphyrin-peptide conjugates with different propensities for self-assembly into various supramolecular nanoarchitectures play important roles in advanced...
Multifunctional porphyrin-peptide conjugates with different propensities for self-assembly into various supramolecular nanoarchitectures play important roles in advanced materials and biomedical research. However, preparing prefunctionalized core porphyrins by traditional low-yielding statistical synthesis and purifying them after peptide ligation through many rounds of HPLC purification is tedious and unsustainable. Herein, we report a novel integrated solid-phase synthetic protocol for the construction of porphyrin moieties from simple aldehydes and dipyrromethanes on resin-bound peptides directly to form mono-, cis/trans-di-, and trivalent porphyrin-peptide conjugates in a highly efficient and controllable manner; moreover, only single final-stage HPLC purification of the products is needed. This efficient strategy enables the rapid, greener, and substrate-controlled diversity-oriented synthesis of multivalent porphyrin-(long) peptide conjugate libraries for multifarious biological and materials applications.
Topics: Peptides; Porphyrins
PubMed: 35730925
DOI: 10.1002/anie.202207532 -
Proceedings of the National Academy of... Aug 2022Elucidating the underlying photochemical mechanisms of action (MoA) of photodynamic therapy (PDT) may allow its efficacy to be improved and could set the stage for the...
Elucidating the underlying photochemical mechanisms of action (MoA) of photodynamic therapy (PDT) may allow its efficacy to be improved and could set the stage for the development of new classes of PDT photosensitizers. Here, we provide evidence that "photoredox catalysis in cells," wherein key electron transport pathways are disrupted, could constitute a general MoA associated with PDT. Taking the cellular electron donor nicotinamide adenine dinucleotide as an example, we have found that well-known photosensitizers, such as Rose Bengal, BODIPY, phenoselenazinium, phthalocyanine, and porphyrin derivatives, are able to catalyze its conversion to NAD. This MoA stands in contrast to conventional type I and type II photoactivation mechanisms involving electron and energy transfer, respectively. A newly designed molecular targeting photocatalyst (termed CatER) was designed to test the utility of this mechanism-based approach to photosensitizer development. Photoexcitation of CatER induces cell pyroptosis via the caspase 3/GSDME pathway. Specific epidermal growth factor receptor positive cancer cell recognition, high signal-to-background ratio tumor imaging (SBRTI = 12.2), and good tumor growth inhibition (TGI = 77.1%) are all hallmarks of CatER. CatER thus constitutes an effective near-infrared pyroptotic cell death photo-inducer. We believe the present results will provide the foundation for the synthesis of yet-improved phototherapeutic agents that incorporate photocatalytic chemistry into their molecular design.
Topics: Antineoplastic Agents; Catalysis; Cell Line, Tumor; Humans; Neoplasms; Photochemotherapy; Photosensitizing Agents; Porphyrins
PubMed: 35969782
DOI: 10.1073/pnas.2210504119 -
International Journal of Nanomedicine 2020Local recurrences of glioblastoma (GBM) after heavy standard treatments remain frequent and lead to a poor prognostic. Major challenges are the infiltrative part of the...
BACKGROUND
Local recurrences of glioblastoma (GBM) after heavy standard treatments remain frequent and lead to a poor prognostic. Major challenges are the infiltrative part of the tumor tissue which is the ultimate cause of recurrence. The therapeutic arsenal faces the difficulty of eradicating this infiltrating part of the tumor tissue while increasing the targeting of tumor and endogenous stromal cells such as angiogenic endothelial cells. In this aim, neuropilin-1 (NRP-1), a transmembrane receptor mainly overexpressed by endothelial cells of the tumor vascular system and associated with malignancy, proliferation and migration of GBM, highlighted to be a relevant molecular target to promote the anti-vascular effect of photodynamic therapy (VTP).
METHODS
The multiscale selectivity was investigated for KDKPPR peptide moiety targeting NRP-1 and a porphyrin molecule as photosensitizer (PS), both grafted onto original AGuIX design nanoparticle. AGuIX nanoparticle, currently in Phase II clinical trials for the treatment of brain metastases with radiotherapy, allows to achieve a real-time magnetic resonance imaging (MRI) and an accumulation in the tumor area by EPR (enhanced permeability and retention) effect. Using surface-plasmon resonance (SPR), we evaluated the affinities of KDKPPR and scramble free peptides, and also peptides-conjugated AGuIX nanoparticles to recombinant rat and human NRP-1 proteins. For in vivo selectivity, we used a cranial window model and parametric maps obtained from T2*-weighted perfusion MRI analysis.
RESULTS
The photophysical characteristics of the PS and KDKPPR molecular affinity for recombinant human NRP-1 proteins were maintained after the functionalization of AGuIX nanoparticle with a dissociation constant of 4.7 μM determined by SPR assays. Cranial window model and parametric maps, both revealed a prolonged retention in the vascular system of human xenotransplanted GBM. Thanks to the fluorescence of porphyrin by non-invasive imaging and the concentration of gadolinium evaluated after extraction of organs, we checked the absence of nanoparticle in the brains of tumor-free animals and highlighted elimination by renal excretion and hepatic metabolism.
CONCLUSION
Post-VTP follow-ups demonstrated promising tumor responses with a prolonged delay in tumor growth accompanied by a decrease in tumor metabolism.
Topics: Animals; Endothelial Cells; Gadolinium; Glioblastoma; Humans; Molecular Targeted Therapy; Nanoparticles; Neoplasm Metastasis; Neuropilin-1; Photochemotherapy; Porphyrins; Precision Medicine; Rats; Theranostic Nanomedicine; Tissue Distribution
PubMed: 33223826
DOI: 10.2147/IJN.S261352 -
International Journal of Molecular... Jul 2022Mitochondria are essential organelles of mammalian cells, often emphasized for their function in energy production, iron metabolism and apoptosis as well as heme... (Review)
Review
Mitochondria are essential organelles of mammalian cells, often emphasized for their function in energy production, iron metabolism and apoptosis as well as heme synthesis. The heme is an iron-loaded porphyrin behaving as a prosthetic group by its interactions with a wide variety of proteins. These complexes are termed hemoproteins and are usually vital to the whole cell comportment, such as the proteins hemoglobin, myoglobin or cytochromes, but also enzymes such as catalase and peroxidases. The building block of porphyrins is the 5-aminolevulinic acid, whose exogenous administration is able to stimulate the entire heme biosynthesis route. In neoplastic cells, this methodology repeatedly demonstrated an accumulation of the ultimate heme precursor, the fluorescent protoporphyrin IX photosensitizer, rather than in healthy tissues. While manifold players have been proposed, numerous discrepancies between research studies still dispute the mechanisms underlying this selective phenomenon that yet requires intensive investigations. In particular, we wonder what are the respective involvements of enzymes and transporters in protoporphyrin IX accretion. Is this mainly due to a boost in protoporphyrin IX anabolism along with a drop of its catabolism, or are its transporters deregulated? Additionally, can we truly expect to find a universal model to explain this selectivity? In this report, we aim to provide our peers with an overview of the currently known mitochondrial heme metabolism and approaches that could explain, at least partly, the mechanism of protoporphyrin IX selectivity towards cancer cells.
Topics: Aminolevulinic Acid; Animals; Heme; Iron; Mammals; Neoplasms; Porphyrins; Protoporphyrins
PubMed: 35887311
DOI: 10.3390/ijms23147974 -
Nature Communications Nov 2022The nuclear receptor REV-ERB plays an important role in a range of physiological processes. REV-ERB behaves as a ligand-dependent transcriptional repressor and heme has...
The nuclear receptor REV-ERB plays an important role in a range of physiological processes. REV-ERB behaves as a ligand-dependent transcriptional repressor and heme has been identified as a physiological agonist. Our current understanding of how ligands bind to and regulate transcriptional repression by REV-ERB is based on the structure of heme bound to REV-ERB. However, porphyrin (heme) analogues have been avoided as a source of synthetic agonists due to the wide range of heme binding proteins and potential pleotropic effects. How non-porphyrin synthetic agonists bind to and regulate REV-ERB has not yet been defined. Here, we characterize a high affinity synthetic REV-ERB agonist, STL1267, and describe its mechanism of binding to REV-ERB as well as the method by which it recruits transcriptional corepressor both of which are unique and distinct from that of heme-bound REV-ERB.
Topics: Nuclear Receptor Subfamily 1, Group D, Member 1; Heme; Ligands; Porphyrins
PubMed: 36414641
DOI: 10.1038/s41467-022-34892-4 -
Biomolecules Sep 2021The evidence that telomerase is overexpressed in almost 90% of human cancers justifies the proposal of this enzyme as a potential target for anticancer drug design. The... (Review)
Review
The evidence that telomerase is overexpressed in almost 90% of human cancers justifies the proposal of this enzyme as a potential target for anticancer drug design. The inhibition of telomerase by quadruplex stabilizing ligands is being considered a useful approach in anticancer drug design proposals. Several aromatic ligands, including porphyrins, were exploited for telomerase inhibition by adduct formation with G-Quadruplex (GQ). 5,10,15,20-Tetrakis(-methyl-4-pyridinium)porphyrin (HTMPyP) is one of the most studied porphyrins in this field, and although reported as presenting high affinity to GQ, its poor selectivity for GQ over duplex structures is recognized. To increase the desired selectivity, porphyrin modifications either at the peripheral positions or at the inner core through the coordination with different metals have been handled. Herein, studies involving the interactions of TMPyP and analogs with different DNA sequences able to form GQ and duplex structures using different experimental conditions and approaches are reviewed. Some considerations concerning the structural diversity and recognition modes of G-quadruplexes will be presented first to facilitate the comprehension of the studies reviewed. Additionally, considering the diversity of experimental conditions reported, we decided to complement this review with a screening where the behavior of HTMPyP and of some of the reviewed metal complexes were evaluated under the same experimental conditions and using the same DNA sequences. In this comparison under unified conditions, we also evaluated, for the first time, the behavior of the Ag complex of HTMPyP. In general, all derivatives showed good affinity for GQ DNA structures with binding constants in the range of 10-10 M and ligand-GQ stoichiometric ratios of 3:1 and 4:1. A promising pattern of selectivity was also identified for the new Ag derivative.
Topics: Acenaphthenes; Antineoplastic Agents; Binding Sites; G-Quadruplexes; Humans; Ligands; Neoplasms; Porphyrins; Telomerase
PubMed: 34680037
DOI: 10.3390/biom11101404