Biology subjects

Samadi, A.

Publications and source records attributed to Samadi, A..

3 recordsLinked to original sources

bioRxiv2023

Rapid engineering of SARS-CoV-2 therapeutic antibodies to increase breadth of neutralization including XBB.1.5 and BQ.1.1

An antibody panel that broadly neutralizes currently circulating Omicron variants was obtained by in vitro affinity maturation using phage display. Starting from a single parent clone, antibody engineering was performed in iterative stages in real time as variants emerged using a proprietary technology called STage-Enhanced Maturation (STEM). Humanized from a rabbit antibody, the parent clone showed undetectable neutralization of later Omicron variants, while an early stage IgG possessing only an engineered light chain potently neutralizes some BA.2 but not BA.4/BA.5 lineage variants. However, the final heavy and light chain engineered mAbs show potent neutralization of XBB.1.5 and BQ.1.1 by surrogate virus neutralization test, and biolayer interferometry shows pM KD affinity for both variants. Our work not only details novel therapeutic candidates but also validates a unique general strategy to create broadly neutralizing mAbs to current and future SARS-CoV-2 variants.

immunology↗

bioRxiv2022

Extracellular ATP drives pancreatic cancer cell invasion via purinergic receptor-integrin interactions

Pancreatic ductal adenocarcinoma (PDAC) is a cancer of unmet clinical need. Given the elevated ATP levels seen in PDAC, the purinergic axis represents an attractive therapeutic target. Mediated in part by highly druggable extracellular proteins, it plays essential roles in fibrosis, inflammation response and immune function. We have analysed the PDAC purinome using publicly available databases to discern which members may impact patient survival. We identified P2RY2 to be the purinergic gene with the strongest association to hypoxia, the highest cancer cell specific expression and the strongest impact on overall survival. Invasion assays using a 3D spheroid model revealed P2Y2 to be critical in facilitating invasion driven by extracellular ATP. Using genetic modification or pharmacological strategies we identify the mechanism of this ATP-driven invasion to require direct protein-protein interactions between P2Y2 and V integrins. Using DNA-PAINT super-resolution fluorescence microscopy, we found that P2Y2 regulates the amount and distribution of integrin V in the plasma membrane. This work highlights a novel GPCR-integrin interaction in cancer invasion and its potential for therapeutic targeting.

cancer biology↗

bioRxiv2022

Potassium homeostasis and signaling as a determinant of Echinacea species tolerance to salinity stress

Salt tolerant is strongly related to potassium (K+) retention in plant tissues under salt stress conditions. However, it is unclear for different Echinacea species. So, mechanistic basis of four Echinacea species (i.e. Echinacea purpurea, Echinacea angustifolia, Echinacea pallida, and Echinacea sanguinea) to salinity stress tolerance, and K+ retention were assessed in the present study. Non-invasive microelectrode ion flux measuring, DHAR and MDHAR activities, and pharmacological measurements were performed based on the standard methods. Ion flux measurements revealed higher K+ efflux in E. pallida and E. sanguinea species compared to the E. purpurea and E. angustifolia species in the elongation zone. Higher salinity-induced H+ efflux was found in the elongation zone than mature zone. However, E. angustifolia and E. purpurea had more Ca2+ influx compared to E. pallida and E. sanguinea species. Net K+ efflux decreased (> 90%) in the presence of TEA and GdCl3. Increasing of Ca2+ uptake and K+ loss in four Echinacea species roots were found in the presence of 0.3 mM Cu/Ascorbate (Cu/Asc). The significant role of H+-ATPase in H+ efflux was demonstrated by Sodium orthovanadate. Ultimately, the physiological properties of Echinacea species have a critical role in salinity-resistant/sensitive differences. Future scientific understanding of Echinacea species physiognomies may be necessary for better understanding of the plant behavior to salinity stress. One-sentence summaryHigher K+ efflux in E. pallida and E. sanguinea species as a result of NaCl and ROS act as a metabolic switch to save energy for adaptations and repairs in salinity stress conditions.

plant biology↗