Photodynamic inactivation of E. coli with cationic imidazolyl-porphyrin photosensitizers and their synergic combination with antimicrobial cinnamaldehyde.

Bacterial infections are a global health concern, particularly due to the increasing resistance of bacteria to antibiotics. Multi-drug resistance (MDR) is a considerable challenge, and novel approaches are needed to treat bacterial infections. Photodynamic inactivation (PDI) of microorganisms is increasingly recognized as an effective method to inactivate a broad spectrum of bacteria and overcome resistance mechanisms. This study presents the synthesis of a new cationic 5,15-di-imidazolyl porphyrin derivative and the impact of n-octanol/water partition coefficient (logP) values of this class of photosensitizers on PDI efficacy of Escherichia coli. The derivative with logP = -0.5, IP-H-OH2+, achieved a remarkable 3 log CFU reduction of E. coli at 100 nM with only 1.36 J/cm2 light dose at 415 nm, twice as effective as the second-best porphyrin IP-H-Me2+, of logP = -1.35. We relate the rapid uptake of IP-H-OH2+ by E. coli to improved PDI and the very low uptake of a fluorinated derivative, IP-H-CF32+, logP ≈ 1, to its poor performance. Combination of PDI with cinnamaldehyde, a major component of the cinnamon plant known to alter bacteria cell membranes, offered synergic inactivation of E. coli (7 log CFU reduction), using 50 nM of IP-H-OH2+ and just 1.36 J/cm2 light dose. The success of combining PDI with this natural compound broadens the scope of therapies for MDR infections that do not add drug resistance. In vivo studies on a mouse model of wound infection showed the potential of cationic 5,15-di-imidazolyl porphyrins to treat clinically relevant infected wounds.

Refining antimicrobial photodynamic therapy: effect of charge distribution and central metal ion in fluorinated porphyrins on effective control of planktonic and biofilm bacterial forms.

Antibiotic resistance represents a pressing global health challenge, now acknowledged as a critical concern within the framework of One Health. Photodynamic inactivation of microorganisms (PDI) offers an attractive, non-invasive approach known for its flexibility, independence from microbial resistance patterns, broad-spectrum efficacy, and minimal risk of inducing resistance. Various photosensitizers, including porphyrin derivatives have been explored for pathogen eradication. In this context, we present the synthesis, spectroscopic and photophysical characteristics as well as antimicrobial properties of a palladium(II)-porphyrin derivative (PdF2POH), along with its zinc(II)- and free-base counterparts (ZnF2POH and F2POH, respectively). Our findings reveal that the palladium(II)-porphyrin complex can be classified as an excellent generator of reactive oxygen species (ROS), encompassing both singlet oxygen (Φ△ = 0.93) and oxygen-centered radicals. The ability of photosensitizers to generate ROS was assessed using a variety of direct (luminescence measurements) and indirect techniques, including specific fluorescent probes both in solution and in microorganisms during the PDI procedure. We investigated the PDI efficacy of F2POH, ZnF2POH, and PdF2POH against both Gram-negative and Gram-positive bacteria. All tested compounds proved high activity against Gram-positive species, with PdF2POH exhibiting superior efficacy, leading to up to a 6-log reduction in S. aureus viability. Notably, PdF2POH-mediated PDI displayed remarkable effectiveness against S. aureus biofilm, a challenging target due to its complex structure and increased resistance to conventional treatments. Furthermore, our results show that PDI with PdF2POH is more selective for bacterial than for mammalian cells, particularly at lower light doses (up to 5 J/cm2 of blue light illumination). This enhanced efficacy of PdF2POH-mediated PDI as compared to ZnF2POH and F2POH can be attributed to more pronounced ROS generation by palladium derivative via both types of photochemical mechanisms (high yields of singlet oxygen generation as well as oxygen-centered radicals). Additionally, PDI proved effective in eliminating bacteria within S. aureus-infected human keratinocytes, inhibiting infection progression while preserving the viability and integrity of infected HaCaT cells. These findings underscore the potential of metalloporphyrins, particularly the Pd(II)-porphyrin complex, as promising photosensitizers for PDI in various bacterial infections, warranting further investigation in advanced infection models.

Binding mechanism and biological effects of flavone DYRK1A inhibitors for the design of new antidiabetics.

The selective inhibition of kinases from the diabetic kinome is known to promote the regeneration of beta cells and provide an opportunity for the curative treatment of diabetes. The effect can be achieved by carefully tailoring the selectivity of inhibitor toward a particular kinase, especially DYRK1A, previously associated with Down syndrome and Alzheimer's disease. Recently DYRK1A inhibition has been shown to promote both insulin secretion and beta cells proliferation. Here, we show that commonly available flavones are effective inhibitors of DYRK1A. The observed biochemical activity of flavone compounds is confirmed by crystal structures solved at 2.06 Å and 2.32 Å resolution, deciphering the way inhibitors bind in the ATP-binding pocket of the kinase, which is driven by the arrangement of hydroxyl moieties. We also demonstrate antidiabetic properties of these biomolecules and prove that they could be further improved by therapy combined with TGF-ß inhibitors. Our data will allow future structure-based optimization of the presented scaffolds toward potent, bioavailable and selective anti-diabetic drugs.

DYRK1A inhibitors leucettines and TGF-ß inhibitor additively stimulate insulin production in beta cells, organoids, and isolated mouse islets.

The decreased ß-cell mass and impaired ß-cell functionality are the primary causes of diabetes mellitus (DM). Nevertheless, the underlying molecular mechanisms by which ß-cell growth and function are controlled are not fully understood. In this work, we show that leucettines, known to be DYRK1A kinase inhibitors, can improve glucose-stimulated insulin secretion (GSIS) in rodent ß-cells and isolated islets, as well as in hiPSC-derived ß-cells islets. We confirm that DYRK1A is expressed in murine insulinoma cells MIN6. In addition, we found that treatment with selected leucettines stimulates proliferation of ß-cells and promotes MIN6 cell cycle progression to the G2/M phase. This effect is also confirmed by increased levels of cyclin D1, which is highly responsive to proliferative signals. Among other leucettines, leucettine L43 had a negligible impact on ß-cell proliferation, but markedly impair GSIS. However, leucettine L41, in combination with LY364947, a, a potent and selective TGF-ß type-I receptor, significantly promotes GSIS in various cellular diabetic models, including MIN6 and INS1E cells in 2D and 3D culture, iPSC-derived ß-cell islets derived from iPSC, and isolated mouse islets, by increased insulin secretion and decreased glucagon level. Our findings confirm an important role of DYRK1A inhibitors as modulators of ß-cells function and suggested a new potential target for antidiabetic therapy. Moreover, we show in detail that leucettine derivatives represent promising antidiabetic agents and are worth further evaluation, especially in vivo.

Liposomal Binuclear Ir(III)-Cu(II) Coordination Compounds with Phosphino-Fluoroquinolone Conjugates for Human Prostate Carcinoma Treatment.

Novel heteronuclear IrIII-CuII coordination compounds ([Ir(η5-Cp*)Cl2Pcfx-Cu(phen)](NO3)·1.75(CH3OH)·0.75(H2O) (1), [Ir(η5-Cp*)Cl2Pnfx-Cu(phen)](NO3)·1.75(CH3OH)·0.75(H2O) (2), [Ir(η5-Cp*)Cl2Plfx-Cu(phen)](NO3)·1.3(H2O)·1.95(CH3OH) (3), [Ir(η5-Cp*)Cl2Psfx-Cu(phen)] (4)) bearing phosphines derived from fluoroquinolones, namely, sparfloxacin (Hsfx), ciprofloxacin (Hcfx), lomefloxacin (Hlfx), and norfloxacin (Hnfx), have been synthesized and studied as possible anticancer chemotherapeutics. All compounds have been characterized by electrospray ionization mass spectrometry (ESI-MS), a number of spectroscopic methods (i.e., IR, fluorescence, and electron paramagnetic resonance (EPR)), cyclic voltammetry, variable-temperature magnetic susceptibility measurements, and X-ray diffractometry. The coordination geometry of IrIII in all complexes adopts a characteristic piano-stool geometry with the η5-coordinated and three additional sites occupied by two chloride and phosphine ligands, while CuII ions in complexes 1 and 2 form a distorted square-pyramidal coordination geometry, and in complex 3, the coordination geometry around CuII ions is a distorted octahedron. Interestingly, the crystal structure of [Ir(η5-Cp*)Cl2Plfx-Cu(phen)] features the one-dimensional (1D) metal-organic polymer. Liposomes loaded with redox-active and fluorescent [Ir(η5-Cp*)Cl2Pcfx-Cu(phen)] (1L) have been prepared to increase water solubility and minimize serious systemic side effects. It has been proven, by confocal microscopy and an inductively coupled plasma mass spectrometry (ICP-MS) analysis, that the liposomal form of compound 1 can be effectively accumulated inside human lung adenocarcinoma and human prostate carcinoma cells with selective localization in nuclei. A cytometric analysis showed dominance of apoptosis over the other cell death types. Furthermore, the investigated nanoformulations induced changes in the cell cycle, leading to S phase arrest in a dose-dependent manner. Importantly, in vitro anticancer action on three-dimensional (3D) multicellular tumor spheroids has been demonstrated.

Synthesis and Characterization of Size- and Charge-Tunable Silver Nanoparticles for Selective Anticancer and Antibacterial Treatment.

Advances in the research of nanoparticles (NPs) with controlled charge and size are driven by their potential application in the development of novel technologies and innovative therapeutics. This work reports the synthesis, characterization, and comprehensive biological evaluation of AgNPs functionalized by N,N,N-trimethyl-(11-mercaptoundecyl) ammonium chloride (TMA) and trisodium citrate (TSC). The prepared AgNPs were well characterized in terms of their morphological, spectroscopic and functional properties and biological activities. The implementation of several complementary techniques allowed not only the estimation of the average particle size (from 3 to 40 nm depending on the synthesis procedure used) but also the confirmation of the crystalline nature of the NPs and their round shape. To prove the usefulness of these materials in biological systems, cellular uptake and cytotoxicity in microbial and mammalian cells were determined. Positively charged 10 nm Ag@TMA2 revealed antimicrobial activity against Gram-negative bacteria with a minimum inhibitory concentration (MIC) value of 0.17 µg/mL and complete eradication of Escherichia coli (7 logs) for Ag@TMA2 at a concentration of 0.50 µg/mL, whereas negatively charged 10 nm Ag@TSC1 was effective against Gram-positive bacteria (MIC = 0.05 µg/mL), leading to inactivation of Staphylococcus aureus at relatively low concentrations. In addition, the largest 40 nm Ag@TSC2 was shown to exhibit pronounced anticancer activity against murine colon carcinoma (CT26) and murine mammary gland carcinoma (4T1) cells cultured as 2D and 3D tumor models and reduced toxicity against human HaCaT keratinocytes. Among the possible mechanisms of AgNPs are their ability to generate reactive oxygen species, which was further evaluated in vitro and correlates well with cellular accumulation and overall activity of AgNPs. Furthermore, we confirmed the anticancer efficacy of the most potent Ag@TSC2 in hiPSC-derived colonic organoids and demonstrated that the NPs are biocompatible and applicable in vivo. A pilot study in BALB/c mice evidenced that the treatment with Ag@TSC2 resulted in temporary (>60 days) remission of CT26 tumors.

Two out of Three Musketeers Fight against Cancer: Synthesis, Physicochemical, and Biological Properties of Phosphino CuI, RuII, IrIII Complexes.

Two novel phosphine ligands, Ph2PCH2N(CH2CH3)3 (1) and Ph2PCH2N(CH2CH2CH2CH3)2 (2), and six new metal (Cu(I), Ir(III) and Ru(II)) complexes with those ligands: iridium(III) complexes: Ir(η5-Cp*)Cl2(1) (1a), Ir(η5-Cp*)Cl2(2) (2a) (Cp*: Pentamethylcyclopentadienyl); ruthenium(II) complexes: Ru(η6-p-cymene)Cl2(1) (1b), Ru(η6-p-cymene)Cl2(2) (2b) and copper(I) complexes: [Cu(CH3CN)2(1)BF4] (1c), [Cu(CH3CN)2(2)BF4] (2c) were synthesized and characterized using elemental analysis, NMR spectroscopy, and ESI-MS spectrometry. Copper(I) complexes turned out to be highly unstable in the presence of atmospheric oxygen in contrast to ruthenium(II) and iridium(III) complexes. The studied Ru(II) and Ir(III) complexes exhibited promising cytotoxicity towards cancer cells in vitro with IC50 values significantly lower than that of the reference drug-cisplatin. Confocal microscopy analysis showed that Ru(II) and Ir(III) complexes effectively accumulate inside A549 cells with localization in cytoplasm and nuclei. A precise cytometric analysis provided clear evidence for the predominance of apoptosis in induced cell death. Furthermore, the complexes presumably induce the changes in the cell cycle leading to G2/M phase arrest in a dose-dependent manner. Gel electrophoresis experiments revealed that Ru(II) and Ir(III) inorganic compounds showed their unusual low genotoxicity towards plasmid DNA. Additionally, metal complexes were able to generate reactive oxygen species as a result of redox processes, proved by gel electrophoresis and cyclic voltamperometry. In vitro cytotoxicity assays were also carried out within multicellular tumor spheroids and efficient anticancer action on these 3D assemblies was demonstrated. It was proven that the hydrocarbon chain elongation of the phosphine ligand coordinated to the metal ions does not influence the cytotoxic effect of resulting complexes in contrast to metal ions type.

DYRK1A Kinase Inhibitors Promote ß-Cell Survival and Insulin Homeostasis.

The rising prevalence of diabetes is threatening global health. It is known not only for the occurrence of severe complications but also for the SARS-Cov-2 pandemic, which shows that it exacerbates susceptibility to infections. Current therapies focus on artificially maintaining insulin homeostasis, and a durable cure has not yet been achieved. We demonstrate that our set of small molecule inhibitors of DYRK1A kinase potently promotes ß-cell proliferation, enhances long-term insulin secretion, and balances glucagon level in the organoid model of the human islets. Comparable activity is seen in INS-1E and MIN6 cells, in isolated mice islets, and human iPSC-derived ß-cells. Our compounds exert a significantly more pronounced effect compared to harmine, the best-documented molecule enhancing ß-cell proliferation. Using a body-like environment of the organoid, we provide a proof-of-concept that small-molecule-induced human ß-cell proliferation via DYRK1A inhibition is achievable, which lends a considerable promise for regenerative medicine in T1DM and T2DM treatment.

Diabetic Kinome Inhibitors-A New Opportunity for ß-Cells Restoration.

Diabetes, and several diseases related to diabetes, including cancer, cardiovascular diseases and neurological disorders, represent one of the major ongoing threats to human life, becoming a true pandemic of the 21st century. Current treatment strategies for diabetes mainly involve promoting ß-cell differentiation, and one of the most widely studied targets for ß-cell regeneration is DYRK1A kinase, a member of the DYRK family. DYRK1A has been characterized as a key regulator of cell growth, differentiation, and signal transduction in various organisms, while further roles and substrates are the subjects of extensive investigation. The targets of interest in this review are implicated in the regulation of ß-cells through DYRK1A inhibition-through driving their transition from highly inefficient and death-prone populations into efficient and sufficient precursors of islet regeneration. Increasing evidence for the role of DYRK1A in diabetes progression and ß-cell proliferation expands the potential for pharmaceutical applications of DYRK1A inhibitors. The variety of new compounds and binding modes, determined by crystal structure and in vitro studies, may lead to new strategies for diabetes treatment. This review provides recent insights into the initial self-activation of DYRK1A by tyrosine autophosphorylation. Moreover, the importance of developing novel DYRK1A inhibitors and their implications for the treatment of diabetes are thoroughly discussed. The evolving understanding of DYRK kinase structure and function and emerging high-throughput screening technologies have been described. As a final point of this work, we intend to promote the term "diabetic kinome" as part of scientific terminology to emphasize the role of the synergistic action of multiple kinases in governing the molecular processes that underlie this particular group of diseases.

Photodynamic Inactivation of Bacteria with Porphyrin Derivatives: Effect of Charge, Lipophilicity, ROS Generation, and Cellular Uptake on Their Biological Activity In Vitro.

Resistance of microorganisms to antibiotics has led to research on various therapeutic strategies with different mechanisms of action, including photodynamic inactivation (PDI). In this work, we evaluated a cationic, neutral, and anionic meso-tetraphenylporphyrin derivative's ability to inactivate the Gram-negative and Gram-positive bacteria in a planktonic suspension under blue light irradiation. The spectroscopic, physicochemical, redox properties, as well as reactive oxygen species (ROS) generation capacity by a set of photosensitizers varying in lipophilicity were investigated. The theoretical calculations were performed to explain the distribution of the molecular charges in the evaluated compounds. Moreover, logP partition coefficients, cellular uptake, and phototoxicity of the photosensitizers towards bacteria were determined. The role of a specific microbial efflux pump inhibitor, verapamil hydrochloride, in PDI was also studied. The results showed that E. coli exhibited higher resistance to PDI than S. aureus (3-5 logs) with low light doses (1-10 J/cm2). In turn, the prolongation of irradiation (up to 100 J/cm2) remarkably improved the inactivation of pathogens (up to 7 logs) and revealed the importance of photosensitizer photostability. The PDI potentiation occurs after the addition of KI (more than 3 logs extra killing). Verapamil increased the uptake of photosensitizers (especially in E. coli) due to efflux pump inhibition. This effect suggests that PDI is mediated by ROS, the electrostatic charge interaction, and the efflux of photosensitizers (PSs) regulated by multidrug-resistance (MDR) systems. Thus, MDR inhibition combined with PDI gives opportunities to treat more resistant bacteria.

Recent advances in strategies for overcoming hypoxia in photodynamic therapy of cancer.

The selectivity of photodynamic therapy (PDT) derived from the tailored accumulation of photosensitizing drug (photosensitizer; PS) in the tumor microenvironment (TME), and from local irradiation, turns it into a "magic bullet" for the treatment of resistant tumors without sparing the healthy tissue and possible adverse effects. However, locally-induced hypoxia is one of the undesirable consequences of PDT, which may contribute to the emergence of resistance and significantly reduce therapeutic outcomes. Therefore, the development of strategies using new approaches in nanotechnology and molecular biology can offer an increased opportunity to eliminate the disadvantages of hypoxia. Emerging evidence indicates that wisely designed phototherapeutic procedures, including: (i) ROS-tunable photosensitizers, (ii) organelle targeting, (iii) nano-based photoactive drugs and/or PS delivery nanosystems, as well as (iv) combining them with other strategies (i.e. PTT, chemotherapy, theranostics or the design of dual anticancer drug and photosensitizers) can significantly improve the PDT efficacy and overcome the resistance. This mini-review addresses the role of hypoxia and hypoxia-related molecular mechanisms of the HIF-1α pathway in the regulation of PDT efficacy. It also discusses the most recent achievements as well as future perspectives and potential challenges of PDT application against hypoxic tumors.