COVID-19 mRNA vaccines effectively reduce incidence of severe disease, hospitalisation and death. The biodistribution and pharmacokinetics of the mRNA-containing lipid nanoparticles (LNPs) in these vaccines are unknown in humans. In this study, we used qPCR to track circulating mRNA in blood at different time-points after BNT162b2 vaccination in a small cohort of healthy individuals. We found that vaccine-associated synthetic mRNA persists in systemic circulation for at least 2 weeks. Furthermore, we used transmission electron microscopy (TEM) to investigate SARS-CoV-2 spike protein expression in human leukemic cells and in primary mononuclear blood cells treated in vitro with the BNT162b2 vaccine. TEM revealed morphological changes suggestive of LNP uptake, but only a small fraction of K562 leukemic cells presented spike-like structures at the cell surface, suggesting reduced levels of expression for these specific phenotypes.

Mutant calreticulin (CALR) proteins resulting from a −1/+2 frameshifting mutation of the CALR exon 9 carry a novel C-terminal amino acid sequence and drive the development of myeloproliferative neoplasms (MPNs). Mutant CALRs were shown to interact with and activate the thrombopoietin receptor (TpoR/MPL) in the same cell. We report that mutant CALR proteins are secreted and can be found in patient plasma at levels up to 160 ng/mL, with a mean of 25.64 ng/mL. Plasma mutant CALR is found in complex with soluble transferrin receptor 1 (sTFR1) that acts as a carrier protein and increases mutant CALR half-life. Recombinant mutant CALR proteins bound and activated the TpoR in cell lines and primary megakaryocytic progenitors from patients with mutated CALR in which they drive thrombopoietin-independent colony formation. Importantly, the CALR-sTFR1 complex remains functional for TpoR activation. By bioluminescence resonance energy transfer assay, we show that mutant CALR proteins produced in 1 cell can specifically interact in trans with the TpoR on a target cell. In comparison with cells that only carry TpoR, cells that carry both TpoR and mutant CALR are hypersensitive to exogenous mutant CALR proteins and respond to levels of mutant CALR proteins similar to those in patient plasma. This is consistent with CALR-mutated cells that expose TpoR carrying immature N-linked sugars at the cell surface. Thus, secreted mutant CALR proteins will act more specifically on the MPN clone. In conclusion, a chaperone, CALR, can turn into a rogue cytokine through somatic mutation of its encoding gene.

The antitumoral activity, and in general, the biological activity is strongly altered by the low uptake of the active agents within the targeted cells. Therefore, lots of efforts have been made to ensure better cellular uptake by using specific carriers. In the present research we have obtained magnetic nanoparticles stabilized by polyethylene glycol (PEG) coating, and functionalized with aspartic acid, which is an important amino acid for protein synthesis and energy production in the body. Such decorated nanoparticles can be internalized by the tumoral cell due to their higher metabolic rate. The nanoparticles were used as a delivery system for antitumoral drugs as cisplatin, carboplatin or irinotecan in a Trojan Horse strategy. Based on the obtained results, it was found that aspartic acid can improve the internalization efficiency of the magnetic carriers after being loaded with antitumoral agents. The nanoparticles are quite stable, can reach and enter the mitochondria and organize around lipid vesicles in quite a high concentration, best results being obtained for the system loaded with cisplatin starting from 0.1 mg/mL.

Mistletoe (Viscum album L.), a semi-parasitic medicinal plant, continues to be of interest, due to its phytochemical composition. The leaves of mistletoe contain phenols, which have a variety of biological effects. The main goal was to characterize the mistletoe that parasitized Robinia pseudoacacia L., (called VAR) in terms of phenolic compounds and to assess the wound healing potential in vitro using the scratch method. Furthermore, the antioxidant capacity was evaluated both by spectrophotometric techniques (DPPH, FRAP, TEAC), as well as by the ability of the mistletoe extract to synthesize green selenium nanoparticles. Among the phenolic acids, dihydroxybenzoic acid is in high level (2.86±0.03 mg/g dw), whereas isorhamnetin-glucuronides dominate the flavonol class (0.593±0.03 mg/g dw). The presence of phenolic compounds in the VAR leaves provides antioxidant capacity. The reducing capacity of VAR extract was demonstrated for the first time by the biosynthesis of nanoselenium particles (NSePs) with a regular, spherical shape and a diameter of around 130 nm. The VAR concentrations of 25-200 µg/mL showed no toxic effect on normal human dermal fibroblasts (NHDF), and the concentration of 100 µg/mL exhibited the best percentage of wound surface closure in vitro (94.08%). The results show that mistletoe is a promising plant because of its phytochemical composition and antioxidant capacity, which can modulate the wound repair process in vitro.

Coated magnetic nanoparticles (MNPs) comprising Fe₃O₄ are a powerful drug delivery system for cancer treatment. They can be preferentially internalized into the tumour cells and release the antitumoral agents on-site. In the present work, we have functionalized the MNPs with glutamic acid which, even if non-essential, is strongly involved in the protein synthesis as a nitrogen donor, being used as a conjugate for specific antitumoral drugs due to its capability to internalize into tumour versus healthy cells faster. The functionalized MNPs were stabilized by polyethylene glycol (PEG) coating. This system improves drug efficacy by concentrating therapeutic agents at the tumour site, and can also induce ferroptosis in cancer cells, an iron-dependent cell death process, which has a beneficial therapeutic effect. Additionally, PEG molecules on the surface of MNPs facilitate drug conjugation for targeted delivery to cancer cells. These MNPs were designed as a delivery system for antitumoral drugs like irinotecan, carboplatin and cisplatin for personalized therapies. Based on the obtained results, it was found that the functionalization with glutamic acid and stabilization with PEG can improve the internalization efficiency of the magnetic carriers into the tumour cells. Owing to their stability, the MNPs can reach and penetrate mitochondria and organize around lipid vesicles, with the most effective results observed for the cisplatin-loaded system from a concentration of 0.1 mg/mL.