Dariusz Śladowski

Fluvastatin increases tyrosinase synthesis induced by α-melanocyte-stimulating hormone in B16F10 melanoma cells

The aim of this study was to evaluate the effect of fluvastatin on the alpha-melanocyte-stimulating hormone-mediated increase in tyrosinase activity in the melanoma B16F10 cell line and to establish whether Akt and extracellular signal-regulated kinase (Erk) inhibition is involved in tyrosinase synthesis after fluvastatin administration. Fluvastatin modulates alpha-melanocyte-stimulating hormone induced melanogenesis by increasing tyrosinase mRNA production, as shown by real time PCR, or tyrosinase protein synthesis, as presented by western blot technique. The stimulatory effect of fluvastatin on melanogenesis was, in part, induced by modulation of cell proliferation (decreased melanoma cell proliferation in G2/M phase) and possibly decrease of Akt. These findings indicate that fluvastatin increases tyrosinase synthesis induced by alpha-melanocyte-stimulating hormone in B16F10 cells and reveal an unknown effect of statin use: their influence on melanin production.

Activation of the complement system as an indicator of pyrogenic reaction to lipopolysaccharide (LPS)

The generation of biologically active complement split products through the direct reaction of microorganisms with complement proteins is one of the earliest events of the defence reaction in humans. Complement activation develops within minutes, which highly corresponds with the onset of a febrile reaction after exposure to pyrogens. The possibility of the use of complement activation in human plasma as an indicator of pyrogen contamination has been tested. Additionally, the co-stimulatory effect of complement activation on tumor necrosis factor-alpha (TNF-alpha) production by blood-separated macrophages exposed to lipopolysaccharide (LPS) has been demonstrated. As an indicator of complement activation in test samples, the concentration of the iC3b fragment was measured by using an ELISA system based on neoantigen formation. The 3-h exposure time has been identified as optimal for the test. The variability between iC3b concentrations in untreated control samples obtained from seven unrelated healthy donors was less than 10%, while after activation by 100 ng/ml LPS, it increased to 13%. The lower detection limit has been identified as 10 pg/ml LPS. As the complement test is not affected by drug-cell interactions or cell viability, the test can be used in situations where tested formulations contain active substances, which interfere with a cell-based test. We conclude that a test based on the detection of complement activation in human plasma should be considered as a valuable element of an in vitro pyrogenicity testing battery along with a cell-based assay.

Synthesis and anticancer activity of 7-hydroxycoumarinyl gallates

BACKGROUND The search for anti-cancer agents includes naturally occurring substances and theirs modifications. Therefore we invented and designed compounds that represent fused derivatives of gallic acid with coumarins. METHODS As a result, a series of 8 novel esters of gallic acid and 7-hydroxycoumarins were synthesized and evaluated for anticancer activity. The structures of the compounds were established by IR, (1)H, (13)C NMR and HR MS spectra. The esters were assayed for antiproliferative activity against human leukemia HL-60 and prostate cancer DU145 cell lines. The activity of novel esters was evaluated by cell viability assays as well as by analysis of cell cycle and cell death mechanism. RESULTS The esters were found to be of similar or higher activity than gallic acid. No pronounced harmful effect was observed in non-cancer cells. CONCLUSIONS The novel compounds represent an excellent starting point for the further optimization and the design of therapeutically effective anti-cancerous drugs.

Dominant ELOVL1 mutation causes neurological disorder with ichthyotic keratoderma, spasticity, hypomyelination and dysmorphic features

Background Ichthyosis and neurological involvement occur in relatively few known Mendelian disorders caused by mutations in genes relevant both for epidermis and neural function. Objectives To identify the cause of a similar phenotype of ichthyotic keratoderma, spasticity, mild hypomyelination (on MRI) and dysmorphic features (IKSHD) observed in two unrelated paediatric probands without family history of disease. Methods Whole exome sequencing was performed in both patients. The functional effect of prioritised variant in ELOVL1 (very-long-chain fatty acids (VLCFAs) elongase) was analysed by VLCFA profiling by gas chromatography–mass spectrometry in stably transfected HEK2932 cells and in cultured patient’s fibroblasts. Results Probands shared novel heterozygous ELOVL1 p.Ser165Phe mutation (de novo in one family, while in the other family, father could not be tested). In transfected cells p.Ser165Phe: (1) reduced levels of FAs C24:0-C28:0 and C26:1 with the most pronounced effect for C26:0 (P=7.8×10−6 vs HEK293 cells with wild type (wt) construct, no difference vs naïve HEK293) and (2) increased levels of C20:0 and C22:0 (P=6.3×10−7, P=1.2×10−5, for C20:0 and C22:0, respectively, comparison vs HEK293 cells with wt construct; P=2.2×10−7, P=1.9×10−4, respectively, comparison vs naïve HEK293). In skin fibroblasts, there was decrease of C26:1 (P=0.014), C28:0 (P=0.001) and increase of C20:0 (P=0.033) in the patient versus controls. There was a strong correlation (r=0.92, P=0.008) between the FAs profile of patient’s fibroblasts and that of p.Ser165Phe transfected HEK293 cells. Serum levels of C20:0–C26:0 FAs were normal, but the C24:0/C22:0 ratio was decreased. Conclusion The ELOVL1 p.Ser165Phe mutation is a likely cause of IKSHD.

Reconstruction method for extended depth-of-field optical diffraction tomography

In the paper we present a novel method of extended depth-of-field limited-angle optical diffraction tomography, in which the change of a focal plane position is performed with a liquid focus-tunable lens. One sinogram is acquired for each state of a focus-tunable lens. After acquisition process is complete, all sinograms are independently reconstructed and stitched to form the final tomographic reconstruction. The presented solution effectively extends the applicability of the Rytov approximation to relatively thick samples and provides uniform resolution of 3D tomographic reconstructions. The method is also combined with Generalized Total Variation Iterative Constraint algorithm, which minimizes distortion of the results due to the limited angular range of acquired projections. The combined solution is dedicated to investigation of transparent and semi-transparent biological micro-structures, like cells and tissue slices.

Feasibility study of investigation of skin at cellular level by digital holographic microscopy

In this paper we propose and implement the systematic approach to investigation of skin tissue based on sequential determination of refractive index and dry mass density for representative skin cells (3T3 fibroblasts and HaCaT keratinocytes) during their growing in a culture from single cells up to formation of a single layer. The main measurement tool is digital holographic microscopy supported by reference measurements performed by holographic tomography. The results of the measurement are presented and discussed.

Xenotransplantation of human cultured parathyroid progenitor cells into mouse peritoneum does not induce rejection reaction.

Introduction Parathyroid progenitor cells devoid of immunogenic antigens were used for human allotransplantation. Although there were many potential reasons for the expiry of transplant activity in humans, we decided to exclude a subclinical form of rejection reaction, and test the rejection reaction in an animal model. Material and methods Experiments were carried out on 40 conventional male mice in their third month of life. The animals were housed in groups of 10 per cage in 4 cages with fitted water dispensers and fed a conventional diet based on standard pellet food. They were divided into four groups of 10 animals each, three experimental groups and one control group. Identified progenitor cells were stored in a cell bank. After testing the phenotype, viability, and absence of immunogenic properties, the cells were transplanted into mouse peritoneum cavity. Results Animals were observed for 9 weeks. At 9 weeks of observation, the mean serum PTH concentration in the experimental groups was 2.0-2.5 pg/ml, while in the control group it did not exceed 1.5 pg/ml. The immunohistochemical assays demonstrated that millions of viable cells with a phenotype identical to the endocrine cells had survived in the peritoneum. Histologic specimens from different internal organs stained for PTH revealed positive cells labelled with anti-PTH Ab in the intestinal lamina, brain, liver, and spleen. Conclusions In the present paper we have demonstrated that xenotransplantation may be used as a model for an explanation of the immunogenic properties of cells generated from postnatal organs for regenerative therapy.