Chain-dependent photocytotoxicity of tricationic porphyrin conjugates and related mechanisms of cell death in proliferating human skin keratinocytes

Enhancing singlet oxygen generation in semiconducting polymer nanoparticles through fluorescence resonance energy transfer for tumor treatment

Photosensitizers (PSs) are of particular importance for efficient photodynamic therapy (PDT). Challenges for PSs simultaneously possessing strong light-absorbing ability, high 1O2 generation by effective intersystem crossing from the singlet to the triplet state, good water-solubility and excellent photostability still exist. Reported here are a new kind of dual-emissive semiconducting polymer nanoparticles (SPNs) containing fluorescent BODIPY derivatives and near-infrared (NIR) phosphorescent iridium(iii) complexes. In the SPNs, the BODIPY units serve as the energy donors in the fluorescence resonance energy transfer (FRET) process for enhancing the light absorption of the SPNs. The NIR emissive iridium(iii) complexes are chosen as the energy acceptors and efficient photosensitizers. The ionized semiconducting polymers can easily self-assemble to form hydrophilic nanoparticles and homogeneously disperse in aqueous solution. Meanwhile, the conjugated backbone of SPNs provides effective shielding for the two luminophores from photobleaching. Thus, an excellent overall performance of the SPN-based PSs has been realized and the high 1O2 yield (0.97) resulting from the synergistic effect of BODIPY units and iridium(iii) complexes through the FRET process is among the best reported for PSs. In addition, owing to the phosphorescence quenching of iridium(iii) complexes caused by 3O2, the SPNs can also be utilized for O2 mapping in vitro and in vivo, which assists in the evaluation of the PDT process and provides important instructions in early-stage cancer diagnosis.

A New Protocol for the Synthesis of New Thioaryl-Porphyrins Derived from 5,10,15,20-Tetrakis(pentafluorophenyl)porphyrin: Photophysical Evaluation and DNA-Binding Interactive Studies

A new protocol for the preparation of thioaryl-porphyrins is described. The compounds were prepared from different disulfides employing NaBH₄ as a reducing agent. The methodology allowed the preparation of four different thioaryl-porphyrins in very-good to excellent yields under soft conditions, such as short reaction times and smooth heating. Additionally, the photophysical properties of new compounds were determined and experimental and theoretical DNA interactions were assessed.

An insight on the role of photosensitizer nanocarriers for Photodynamic Therapy

Photodynamic therapy (PDT) is a modality of cancer treatment in which tumor cells are destroyed by reactive oxygen species (ROS) produced by photosensitizers following its activation with visible or near infrared light. The PDT success is dependent on different factors namely on the efficiency of the photosensitizer deliver and targeting ability. In this review a special attention will be given to the role of some drug delivery systems to improve the efficiency of tetrapyrrolic photosensitizers to this type of treatment.

Inonotus obliquus polysaccharide regulates gut microbiota of chronic pancreatitis in mice

Polysaccharide is efficient in attenuation of metabolic ailments and modulation of gut microbiota as prebiotics. The therapeutic effect of Inonotus obliquus polysaccharide (IOP) on chronic pancreatitis (CP) in mice has been validated in our previous study. However, it is not clear whether IOP is conducive to maintaining the homeostasis between gut microbiota and host. The aim of this study is to testify the potential effects of IOP on gut microbiota composition and diversity in mice with CP. The changes in glutathione peroxidase (GSH-P_X), total antioxidant capacity (TAOC), tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), lipase and trypsin levels were measured by commercial assay kits, meanwhile the gut microbiota composition and diversity were analyzed by high throughput sequencing. The IOP treatment increased GSH-P_X and TAOC levels, and decreased TNF-α, TGF-β, lipase and trypsin levels in CP mice. It was also observed that gut microbiota in IOP treated groups were less diverse than others in terms of lower Shannon diversity index and Chao 1 estimator. IOP increased the proportion of Bacteroidetes and decreased that of Firmicutes at phylum level. Bacteroidetes was found positively correlated with GSH-P_X and TAOC, and Firmicutes correlated with TNF-α, TGF-β, and lipase. In conclusion, administration of IOP could regulate gut microbiota composition and diversity to a healthy profile in mice with CP, and some bacterial phylum significantly correlated with characteristic parameters.

Photodegradation of organic pollutants in water by immobilized porphyrins and phthalocyanines

New methods for water treatment are required as a result from an increasing awareness in the reduction of the pollution impact in the environment. In the perspective of the photo-oxidation of organic pollutants present in water, the principal incentive for the preparation of heterogeneous photocatalysts is their easy recovery from the reaction mixture, which allows their reuse in successive runs, minimizing the loss of their original photocatalytic properties. Different types of supports can be used in the immobilization of photoactive species, such as porphyrins (Pors) and phthalocyanines (Pcs). This mini-review will consider the different methodologies for the immobilization of Pors and Pcs and their photocatalytic performance in the photodegradation of organic pollutants in water, addressing also their recycling ability in successive water treatments.

meso-Mono-[4-(1,4,7-triazacyclononanyl)]-tri(phenyl)]porphyrin and the respective zinc(ii)-complex: complete characterization and biomolecules binding abilities

We aimed to synthesize a new series of triazacyclononanyl-porphyrins (4and5) with the potential ability to bind DNA.

Synthesis, characterization and biomolecule-binding properties of novel tetra-platinum(ii)-thiopyridylporphyrins

New tetra-platinum(ii)-thiopyridylporphyrin complexes and their DNA binding studies.

iASPP is a novel autophagy inhibitor in keratinocytes

The protein iASPP (encoded by PPP1R13L) is an evolutionarily conserved p53 inhibitor, the expression of which is often upregulated in human cancers. We have recently shown that iASPP is a crucial regulator of epidermal homeostasis. Here, we report that iASPP also acts as autophagy inhibitor in keratinocytes. Our data show that depletion of iASPP protects keratinocytes from apoptosis by modulating the expression of Noxa (also known as PMAIP1). In our model, iASPP expression can affect the fission-fusion cycle, mass and shape of mitochondria. iASPP-silenced keratinocytes display disorganization of cytosolic compartments and increased metabolic stress caused by deregulation of mTORC1 signaling. Moreover, increased levels of lipidated LC3 protein confirmed the activation of autophagy in iASPP-depleted cells. We have identified a novel mechanism modulating autophagy in keratinocytes that relies upon iASPP expression specifically reducing the interaction of Atg5-Atg12 with Atg16L1, an interaction that is essential for autophagosome formation or maturation. Using organotypic culture, we further explored the link between autophagy and differentiation, and we showed that impairing autophagy affects epidermal terminal differentiation. Our data provide an alternative mechanism to explain how epithelial integrity is maintained against environmental stressors and might also improve the understanding of the etiology of skin diseases that are characterized by defects in differentiation and DNA damage responses.

Silica nanoparticles functionalized with porphyrins and analogs for biomedical studies

This review focus on the preparation of silica nanoparticles functionalized with porphyrins and related compounds. It is aimed to highlight their features as photosensitizers in the area of photodynamic therapy. In this field, photosensitizers have been covalently and non-covalently linked to silica nanoparticles, in order to study their photophysical and biological properties. Another fascinating scenario for photosensitizer-silica nanoparticles hybrids involves the possibility of including metal cores for conditioning the uptake in the target cells, allowing most of the times the combination of therapies and in certain conditions to facilitate the removal and reutilization of the photosensitizer in environmental applications.