Isotocin controls ion regulation through regulating ionocyte progenitor differentiation and proliferation

The present study using zebrafish as a model explores the role of isotocin, a homolog of oxytocin, in controlling ion regulatory mechanisms. Double-deionized water treatment for 24 h significantly stimulated isotocin mRNA expression in zebrafish embryos. Whole-body Cl−, Ca2+, and Na+ contents, mRNA expressions of ion transporters and ionocyte-differentiation related transcription factors, and the number of skin ionocytes decreased in isotocin morphants. In contrast, overexpression of isotocin caused an increase in ionocyte numbers. Isotocin morpholino caused significant suppression of foxi3a mRNA expression, while isotocin cRNA stimulated foxi3a mRNA expressions at the tail-bud stage of zebrafish embryos. The density of P63 (an epidermal stem cell marker)-positive cells was downregulated by isotocin morpholinos and was upregulated by isotocin cRNA. Taken together, isotocin stimulates the proliferation of epidermal stem cells and differentiation of ionocyte progenitors by regulating the P63 and Foxi3a transcription factors, consequently enhancing the functional activities of ionocytes

Antioxidant activity of polyphenolic extracts from red current and cranberry fruits with regard to erythrocytes membrane

Celem podjętych badań było określenie aktywności przeciwutleniającej wodnych ekstraktów z czerwonej porzeczki i żurawiny w odniesieniu do błony erytrocytów oraz mechanizmu odpowiedzialnego za tę aktywność. Oznaczono skład polifenolowy ekstraktów z zastosowaniem metody chromatografii cieczowej z detektorem diodowym i masowym (UPLC-DAD-MS). Spektrofotometrycznie określono współczynnik podziału związków zawartych w ekstraktach pomiędzy fazę organiczną i wodną. Aktywność przeciwutleniającą ekstraktów wobec błony erytrocytów zbadano metodą fluorymetryczną na podstawie stopnia gaszenia fluorescencji sondy DPH-PA, indukując utlenianie błon erytrocytów związkiem AAPH. Fluorymetrycznie określono również lokalizację w błonie erytrocytów związków polifenolowych zawartych w ekstraktach. Stwierdzono, że owoce czerwonej porzeczki i żurawiny są bogate w związki polifenolowe, szczególnie w antocyjany i procyjanidyny. Wykazano, po zastosowaniu sond fluorescencyjnych, że polifenole zawarte w ekstraktach nie przenikają do części hydrofobowej błony, na co wskazuje brak zmian w anizotropii fluorescencji. Łączą się natomiast z regionem główek polarnych na powierzchni błony, zmieniając ich upakowanie, na co wskazuje zmniejszenie uogólnionej polaryzacji. Dowiedziono, że związki polifenolowe zawarte w ekstraktach skutecznie chronią błonę erytrocytów przed szkodliwym działaniem wolnych rodników indukowanych związkiem AAPH w środowisku wodnym. Ponadto wykazano, że aktywność przeciwutleniająca ekstraktu z czerwonej porzeczki (IC₅₀ = 4,59 μg/ml) jest zbliżona do aktywności standardowego przeciwutleniacza, jakim jest Trolox (IC₅₀ = 3,9 μg/ml), oraz że jest ona wyższa od aktywności ekstraktu żurawiny (IC₅₀ = 12,02 μg/ml).The objective of the research study was to determine the antioxidant activity of aqueous solutions of extracts from red current and cranberry with regard to the erythrocytes membrane, and the mechanism responsible for that activity. The polyphenolic composition of the extracts was determined using an ultraperformance liquid chromatography method with diode array detection and mass analysis (UPLC-DADMS). Spectrophotometrically was determined a partition coefficient for compounds contained in extracts between the organic and aqueous phases. The antioxidant activity of extracts towards the erythrocytes membrane was analyzed using a fluorescence method on the basis of a quenching degree of DPH-PA probe fluorescence, whereas the oxidation of the erythrocytes membranes was induced by an AAPH compound. The fluorescence spectroscopy was also used to determine the location of phenolic compounds, contained in the extracts, in the erythrocyte membrane. It was found that the red currant and cranberry fruits were rich in polyphenols, in particular in anthocyanins and procyanidins. With the use of fluorescence probes, it was proved that polyphenolic compounds contained in the extracts did not penetrate into the hydrophobic region of the membrane; the absence of any changes in the fluorescence anisotropy confirmed it. However, they bound to the region of polar heads on the membrane surface and changed their packing as evidenced by the decrease in the generalized polarization. It was proved that the polyphenols in the extracts efficiently protected the erythrocytes membrane against harmful activity of free radicals induced by the AAPH compound in the aqueous environment. Furthermore, it was proved that the antioxidant activity of red currant extract (IC₅₀ = 4.59 μg/ml) was comparable to that of a standard antioxidant, i.e. of TroloxⓇ (IC₅₀ = 3.9 μg/ml) and that it was better than the activity of cranberry extracts (IC₅₀ = 12.02 μg/ml)

Phospholipid bilayer perturbing-properties underlying lysis induced by pH-sensitive cationic lysine-based surfactants in biomembranes

Many strategies for treating diseases require the delivery of drugs into the cell cytoplasm following internalization within endosomal vesicles. Thus, compounds triggered by low pH to disrupt membranes and release endosomal contents into the cytosol are of particular interest. Here, we report novel cationic lysine-based surfactants (hydrochloride salts of Nε- and Nα-acyl lysine methyl ester) that differ in the position of the positive charge and the length of the alkyl chain. Amino acid-based surfactants could be promising novel biomaterials in drug delivery systems, given their biocompatible properties and low cytotoxic potential. We examined their ability to disrupt the cell membrane in a range of pH values, concentrations and incubation times, using a standard hemolysis assay as a model of endosomal membranes. Furthermore, we addressed the mechanism of surfactant-mediated membrane destabilization, including the effects of each surfactant on erythrocyte morphology as a function of pH. We found that only surfactants with the positive charge on the α-amino group of lysine showed pH-sensitive hemolytic activity and improved kinetics within the endosomal pH range, indicating that the positive charge position is critical for pH-responsive behavior. Moreover, our results showed that an increase in the alkyl chain length from 14 to 16 carbon atoms was associated with a lower ability to disrupt cell membranes. Knowledge on modulating surfactant-lipid bilayer interactions may help us to develop more efficient biocompatible amino acid-based drug delivery devices