Tuning ion channel mechanosensitivity by asymmetry of the transbilayer pressure profile

Mechanical stimuli acting on the cellular membrane are linked to intracellular signaling events and downstream effectors via different mechanoreceptors. Mechanosensitive (MS) ion channels are the fastest known primary mechano-electrical transducers, which convert mechanical stimuli into meaningful intracellular signals on a submillisecond time scale. Much of our understanding of the biophysical principles that underlie and regulate conversion of mechanical force into conformational changes in MS channels comes from studies based on MS channel reconstitution into lipid bilayers. The bilayer reconstitution methods have enabled researchers to investigate the structure-function relationship in MS channels and probe their specific interactions with their membrane lipid environment. This brief review focuses on close interactions between MS channels and the lipid bilayer and emphasizes the central role that the transbilayer pressure profile plays in mechanosensitivity and gating of these fascinating membrane proteins.     

Carotenoid production of Botryococcus braunii CCAP 807/2 under different growth conditions

Journal of Applied Phycology - Botryococcus braunii CCAP 807/2 has been studied intensively for biofuel production due to its high hydrocarbon content. This strain is also capable of producing high...     

The effect of different exogenous kisspeptins on sex hormones and reproductive indices of the goldfish (Carassius auratus) broodstock

Despite several studies on fish hormone therapy, finding new candidates may provide more reproductive efficiency in artificial propagation. Kisspeptins, being upstream of the hypothalamic–pituitary-gonadal axis, appear to play a key role in the reproduction process. In the present study, the effect of different variants of kisspeptide, including goldfish (Carassius auratus) kiss1 kisspeptin (Kiss1), human kisspeptin (Hkiss), and their combination (Kiss1 + H), on the reproductive indices of goldfish broodstock in comparison to Ovaprim (a typical synthetic Gnrh hormone) was investigated. Peptides (Kiss1 and Hkiss) were synthesized using a solid-phase synthesis approach. Kiss1 and Hkiss were injected at a dose of 100 μg kg⁻¹ body weight, blood samples were taken 6 h after injection and sex hormones (E2, Dhp, and 11-Kt), gonadotropins (Lh and Fsh), cortisol and reproductive indices (fecundity, fertilization and hatching percentage) were measured. The results showed a significant increase of plasma sex hormones and gonadotropins in fish treated with kisspeptins. In addition, the cortisol and lipoprotein lipase in Kiss1, Hkiss and Kiss1 + H were remarkably increased compared to Ovaprim. In conclusion, kisspeptins could be a more suitable candidate than Ovaprim for accelerating and synchronizing oocyte maturation in the fisheries industry.     

The phosphatidylinositol 3-kinase signaling pathway exerts protective effects during sepsis by controlling C5a-mediated activation of innate immune functions

The PI3K/Akt signaling pathway has been recently suggested to have controversial functions in models of acute and chronic inflammation. Our group and others have reported previously that the complement split product C5a alters neutrophil innate immunity and cell signaling during the onset of sepsis and is involved in PI3K activation. We report in this study that in vivo inhibition of the PI3K pathway resulted in increased mortality in septic mice accompanied by strongly elevated serum levels of TNF-alpha, IL-6, MCP-1, and IL-10 during sepsis as well as decreased oxidative burst activity in blood phagocytes. PI3K inhibition in vitro resulted in significant increases in TLR-4-mediated generation of various proinflammatory cytokines in neutrophils, whereas the opposite effect was observed in PBMC. Oxidative burst and phagocytosis activity was significantly attenuated in both neutrophils and monocytes when PI3K activation was blocked. In addition, PI3K inhibition resulted in strongly elevated TLR-4-mediated generation of IL-1beta and IL-8 in neutrophils when these cells were co-stimulated with C5a. C5a-induced priming effects on neutrophil and monocyte oxidative burst activity as well as C5a-induced phagocytosis in neutrophils were strongly reduced when PI3K activation was blocked. Our data suggest that the PI3K/Akt signaling pathway controls various C5a-mediated effects on neutrophil and monocyte innate immunity and exerts an overall protective effect during experimental sepsis.     

Structural characterization of an equilibrium unfolding intermediate in cytochrome c

Although the denaturant-induced unfolding transition of cytochrome c was initially thought to be a cooperative process, recent spectroscopic studies have shown deviations from two-state behavior consistent with accumulation of an equilibrium intermediate. However, little is known about the structural and thermodynamic properties of this state, and whether it is stabilized by the presence of non-native heme ligands. We monitored the reversible denaturant-induced unfolding equilibrium of oxidized horse cytochrome c using various spectroscopic probes, including fluorescence, near and far-UV CD, heme absorbance bands in the Soret, visible and near-IR regions of the spectrum, as well as 2D NMR. Global fitting techniques were used for a quantitative interpretation of the results in terms of a three-state model, which enabled us to determine the intrinsic spectroscopic properties of the intermediate. A well-populated intermediate was observed in equilibrium experiments at pH 5 using either guanidine-HCl or urea as a denaturant, both for wild-type cytochrome c as well as an H33N mutant chosen to prevent formation of non-native His-heme ligation. For a more detailed structural characterization of the intermediate, we used 2D 1H-15N correlation spectroscopy to follow the changes in peak intensity for individual backbone amide groups. The equilibrium state observed in our optical and NMR studies contains many native-like structural features, including a well-structured alpha-helical sub-domain, a short Trp59-heme distance and solvent-shielded heme environment, but lacks the native Met80 sulfur-iron linkage and shows major perturbations in side-chain packing and other tertiary interactions. These structural properties are reminiscent of the A-state of cytochrome c, a compact denatured form found under acidic high-salt conditions, as well as a kinetic intermediate populated at a late stage of folding. The denaturant-induced intermediate also resembles alkaline forms of cytochrome c with altered heme ligation, suggesting that disruption of the native methionine ligand favors accumulation of structurally analogous states both in the presence and absence of non-native ligands.     

Induction of regulatory T cells by a murine β-defensin

β-Defensins are antimicrobial peptides of the innate immune system produced in the skin by various stimuli, including proinflammatory cytokines, bacterial infection, and exposure to UV radiation (UVR). In this study we demonstrate that the UVR-inducible antimicrobial peptide murine β-defensin-14 (mBD-14) switches CD4(+)CD25(-) T cells into a regulatory phenotype by inducing the expression of specific markers like Foxp3 and CTLA-4. This is functionally relevant because mBD-14-treated T cells inhibit sensitization upon adoptive transfer into naive C57BL/6 mice. Accordingly, injection of mBD-14, comparable to UVR, suppresses the induction of contact hypersensitivity and induces Ag-specific regulatory T cells (Tregs). Further evidence for the ability of mBD-14 to induce Foxp3(+) T cells is provided using DEREG (depletion of Tregs) mice in which Foxp3-expressing cells can be depleted by injecting diphtheria toxin. mBD-14 does not suppress sensitization in IL-10 knockout mice, suggesting involvement of IL-10 in mBD-14-mediated immunosuppression. However, unlike UVR, mBD-14 does not appear to mediate its immunosuppressive effects by affecting dendritic cells. Accordingly, UVR-induced immunosuppression is not abrogated in mBD-14 knockout mice. Together, these data suggest that mBD-14, like UVR, has the capacity to induce Tregs but does not appear to play a major role in UVR-induced immunosuppression. Through this capacity, mBD-14 may protect the host from microbial attacks on the one hand, but tame T cell-driven reactions on the other hand, thereby enabling an antimicrobial defense without collateral damage by the adaptive immune system.     

Investigating key cell types and molecules dynamics in PyMT mice model of breast cancer through a mathematical model

The most common kind of cancer among women is breast cancer. Understanding the tumor microenvironment and the interactions between individual cells and cytokines assists us in arriving at more effective treatments. Here, we develop a data-driven mathematical model to investigate the dynamics of key cell types and cytokines involved in breast cancer development. We use time-course gene expression profiles of a mouse model to estimate the relative abundance of cells and cytokines. We then employ a least-squares optimization method to evaluate the model’s parameters based on the mice data. The resulting dynamics of the cells and cytokines obtained from the optimal set of parameters exhibit a decent agreement between the data and predictions. We perform a sensitivity analysis to identify the crucial parameters of the model and then perform a local bifurcation on them. The results reveal a strong connection between adipocytes, IL6, and the cancer population, suggesting them as potential targets for therapies.     

Evaluation of electrocoagulation,flocculation, and sedimentation harvesting methods on microalgae consortium grown in anaerobically digested abattoir effluent

Microalgae dewatering is a major bottleneck for biomass production in a large-scale microalgal production system which accounts for 20–60% of production cost. In this study, three dewatering systems of electrocoagulation, flocculation, and pH-induced flocculation were evaluated for microalgal consortium grown in anaerobically digested abattoir effluent at pH 6.5 and 9.5. At the shortest time (15 min) and the highest current density (0.08 A cm^?2), the highest microalgae recoveries of 78 and 84% were obtained with the corresponding power consumptions of 1.25 and 1.07 kWh kg^?1 for cultures at pH 6.5 and 9.5. For microalgae suspension at pH 6.5, the highest biomass recovery of 77% was obtained when 100 mg L^?1 of FeCl₃·6H₂O (after 15 min) or 100 mg L^?1 of Al₂(SO₄)₃·18H₂O (after 30 min) was added. However, microalgal recoveries significantly increased when FeCl₃·6H₂O or Al₂(SO₄)₃·18H₂O was used with the culture at pH 9.5. pH-Induced experiments showed that cultures adjusted at pH 10.5 had 36% higher biomass recovery compared to that in cultures at pH 8.5 after 2 h. The results of this study showed that cultures at higher pH (9.5) had a better microalgae recovery in all dewatering systems than cultures at lower pH (6.5).

     

Potential of chimeric antigen receptor (CAR)‐redirected immune cells in breast cancer therapies: Recent advances

Despite substantial developments in conventional treatments such as surgery, chemotherapy, radiotherapy, endocrine therapy, and molecular‐targeted therapy, breast cancer remains the leading cause of cancer mortality in women. Currently, chimeric antigen receptor (CAR)–redirected immune cell therapy has emerged as an innovative immunotherapeutic approach to ameliorate survival rates of breast cancer patients by eliciting cytotoxic activity against cognate tumour‐associated antigens expressing tumour cells. As a crucial component of adaptive immunity, T cells and NK cells, as the central innate immune cells, are two types of pivotal candidates for CAR engineering in treating solid malignancies. However, the biological distinctions between NK cells‐ and T cells lead to differences in cancer immunotherapy outcomes. Likewise, optimal breast cancer removal via CAR‐redirected immune cells requires detecting safe target antigens, improving CAR structure for ideal immune cell functions, promoting CAR‐redirected immune cells filtration to the tumour microenvironment (TME), and increasing the ability of these engineered cells to persist and retain within the immunosuppressive TME. This review provides a concise overview of breast cancer pathogenesis and its hostile TME. We focus on the CAR‐T and CAR‐NK cells and discuss their significant differences. Finally, we deliver a summary based on recent advancements in the therapeutic capability of CAR‐T and CAR‐NK cells in treating breast cancer.     

Prediction and analysis of multi epitope based vaccine against Newcastle disease virus based on haemagglutinin neuraminidase protein

Newcastle disease virus (NDV), an avian orthoavulavirus, is a causative agent of Newcastle disease named (NDV), and can cause even the epidemics when disease is not treated. Previously several vaccines based on attenuated and inactivated viruses have been reported which are rendered useless with the passage of time due to versatile changes in viral genome. Therefore, we aimed to develop an effective multi-epitope vaccine against the haemagglutinin neuraminidase (HN) protein of 26 NDV strains from Pakistan through a modern immunoinformatic approaches. As a result, a vaccine chimaera was constructed by combining T-cell and B-cell epitopes with the appropriate linkers and adjuvant. The designed vaccine was highly immunogenic, non-allergen and antigenic; therefore, the potential 3D-structureof multi epitope vaccine was constructed, refined and validated. A molecular docking study of a multiepitope vaccine candidate with the chicken Toll-like receptor-4 indicated successful binding. An In silico immunological simulation was used to evaluate the candidate vaccine''s ability to elicit an effective immune response. According to the computational studies, the proposed multiepitope vaccine is physically stable and may induce immune responses whichsuggested it a strong candidate against 26 Newcastle disease virus strains from Pakistan.