Advantageous/Unfavorable Effect of Quercetin on the Membranes of SK-N-SH Neuroblastoma Cells

Exploring the effects of three-finger toxins from Naja ashei venom on neuronal and immunological cancer cell membranes

Three-finger proteins are the most abundant toxins in the venom of Naja ashei, a snake species from the Elapidae family. This research aimed to describe the effects of varying charges of these proteins, isolated from Naja ashei venom using SEC and IEX chromatography. The study examined how differently charged three-finger toxin fractions interact with and affect neuroblastoma (SK-N-SH) and promyeloblast (HL-60) cells, as well as model Langmuir membranes and liposomes designed to mimic cellular lipid composition. Findings revealed that protein surface charges significantly impact cell survival (MTT assay), membrane damage (lactate dehydrogenase release, malondialdehyde formation), and the structural and electrochemical properties of model membranes (Langmuir membranes and zeta potential for liposomes and cancer cell lines). Results indicated that SK-N-SH cells, characterized by a higher negative charge on their cell membranes, interacted more effectively with positively charged toxins than HL-60 cells. However, the mechanism of these electrostatic interactions is complex. The research demonstrated that electrostatic and mechanical membrane modifications induced by venom proteins can significantly affect cell metabolism. Additionally, the total charge of the membrane, influenced by polar lipid components and phospholipid saturation, plays a decisive role in toxin interaction.

Mitigation of Insulin Resistance by Natural Products from a New Class of Molecules, Membrane-Active Immunomodulators

Insulin resistance (IR), accompanied by an impaired cellular glucose uptake, characterizes diverse pathologies that include, but are not limited to, metabolic disease, prediabetes and type 2 diabetes. Chronic inflammation associated with deranged cellular signaling is thought to contribute to IR. The key molecular players in IR are plasma membrane proteins, including the insulin receptor and glucose transporter 4. Certain natural products, such as lipids, phenols, terpenes, antibiotics and alkaloids have beneficial effects on IR, yet their mode of action remains obscured. We hypothesized that these products belong to a novel class of bioactive molecules that we have named membrane-active immunomodulators (MAIMs). A representative MAIM, the naturally occurring medium chain fatty acid ester diethyl azelate (DEA), has been shown to increase the fluidity of cell plasma membranes with subsequent downstream effects on cellular signaling. DEA has also been shown to improve markers of IR, including blood glucose, insulin and lipid levels, in humans. The literature supports the notion that DEA and other natural MAIMs share similar mechanisms of action in improving IR. These findings shed a new light on the mechanism of IR mitigation using natural products, and may facilitate the discovery of other compounds with similar activities.

Foliar Application of Wood Distillate Alleviates Ozone-Induced Damage in Lettuce (Lactuca sativa L.)

This study examined whether foliar applications of wood distillate (WD) have a protective effect on photosynthesis and the antioxidant power of lettuce when exposed to an ecologically relevant O₃ concentration. Seedlings of lettuce (Lactuca sativa L.) were fumigated daily with 60 ppb of O₃ for 30 days, five hours per day. Once per week, 50% of the fumigated plants were treated with foliar applications of 0.2% WD, while control plants were treated with water. The results clearly showed the ability of WD to protect lettuce plants from ozone-induced damage. Specifically, WD-treated plants exhibited lower damage to the photosynthetic machinery, assessed through a series of chlorophyll fluorescence parameters, a higher chlorophyll content, higher antioxidant power, as well as antioxidant molecules, i.e., caffeic acid and quercetin, and higher biomass. Counteracting the overproduction of ozone-generated reactive oxygen species (ROS) is speculated to be the main mechanism by which WD protects the plant from ozone-induced damage.