Protein targeting to starch 1, a functional protein of starch biosynthesis in wheat (Triticum aestivum L.).

KEY MESSAGE: TaPTST1, a wheat homolog of AtPTST1 containing CBM can interact with GBSSI and regulate starch metabolism in wheat endosperm. In cereal endosperm, native starch comprising amylose and amylopectin is synthesized by the coordinated activities of several pathway enzymes. Amylose in starch influences its physio-chemical properties resulting in several human health benefits. The Granule-Bound Starch Synthase I (GBSSI) is the most abundant starch-associated protein. GBSSI lacks dedicated Carbohydrate-binding module (CBM). Previously, Protein Targeting To Starch 1 (PTST1) was identified as a crucial protein for the localization of GBSSI to the starch granules in Arabidopsis. The function of its homologous protein in the wheat endosperm is not known. In this study, TaPTST1, an AtPTST1 homolog, containing a CBM and a coiled-coil domain was identified in wheat. Protein-coding nucleotide sequence of TaPTST1 from Indian wheat variety 'C 306' was cloned and characterized. Homology modelling and molecular docking suggested the potential interaction of TaPTST1 with glucans and GBSSI. The TaPTST1 expression was higher in wheat grain than the other tissues, suggesting a grain-specific function. In vitro binding assays demonstrated different binding affinities of TaPTST1 for native starch, amylose, and amylopectin. Furthermore, the immunoaffinity pull-down assay revealed that TaPTST1 directly interacts with GBSSI, and the interaction is mediated by a coiled-coil domain. The direct protein-protein interaction was further confirmed by bimolecular fluorescence complementation assay (BiFC) in planta. Based on our findings we postulate a functional role for TaPTST1 in starch metabolism by targeting GBSSI to starch granules in wheat endosperm.

Diosgenin loaded cellulose nanoonion impedes different stages of protein aggregation induced cell death via alleviating mitochondrial dysfunction and upregulation of autophagy.

Protein aggregation is a multifaceted phenomenon prevalent in the progression of neurodegenerative diseases, yielding aggregates of diverse sizes. Recently, increased attention has been directed towards early protein aggregates due to their pronounced toxicity, largely stemming from inflammation mediated by reactive oxygen species (ROS). This study advocates for a therapeutic approach focusing on inflammation control rather than mere ROS inhibition in the context of neurodegenerative disorders. Here, we introduced Camellia sinensis cellulose nanoonion (CS-CNO) as an innovative, biocompatible nanocarrier for encapsulating the phytosteroid diosgenin (DGN@CS-CNO). The resulting nano-assembly, manifesting as spherical entities with dimensions averaging ~180-220 nm, exhibits a remarkable capacity for the gradual and sustained release of approximately 39-44 % of DGN over a 60-hour time frame. DGN@CS-CNO displays a striking ability to inhibit or disassemble various phases of hen egg white lysozyme (HEWL) protein aggregates, including the early (HEWLEA) and late (HEWLLA) stages. In vitro experiments employing HEK293 cells underscore the potential of DGN@CS-CNO in mitigating cell death provoked by protein aggregation. This effect is achieved by ameliorating ROS-mediated inflammation and countering mitochondrial dysfunction, as evidenced by alterations in TNFα, TLR4, and MT-CO1 protein expression. Western blot analyses reveal that the gradual and sustained release of DGN from DGN@CS-CNO induces autophagy, a pivotal process in dismantling intracellular amyloid deposits. In summary, this study not only illuminates a path forward but also presents a compelling case for the utilization of phytosteroid as a formidable strategy against neuroinflammation incited by protein aggregation.

Transferrin Immobilized Graphene Oxide Nanocomposite for Targeted Cancer Chemodynamic Therapy via Increasing Intracellular Labile Fe2+ Concentration.

Recently, different alternative regulated cell death (RCD) pathways, viz., necroptosis, pyroptosis, ferroptosis, cuproptosis etc., have been explored as important targets for the development of cancer medications in recent years, as these can change the immunogenicity of the tumor microenvironment (TME) and will finally lead to the inhibition of cancer progression and metastasis. Here, we report the development of transferrin immobilized graphene oxide (Tfn@GOAPTES) nanocomposite as a therapeutic strategy toward cancer cell killing. The electrostatic immobilization of Tfn on the GOAPTES surface was confirmed by different spectroscopy and microscopy techniques. The Tfn immobilization was found to be ∼74 ± 4%, whereas the stability of the protein on the GO surface suggested a robust nature of the nanocomposite. The MTT assay suggested that Tfn@GOAPTES exhibited cytotoxicity toward HeLa cells via increased lipid peroxidation and DNA damage. Western blot studies resulted in decreased expression of acetylation on lysine 40 of α-tubulin and increased expression of LC3a/b for Tfn@GOAPTES treated HeLa cells, suggesting autophagy to be the main cause of the cell death mechanism. Overall, we predict that the present approach can be used as a therapeutic strategy for cancer cell killing via selective induction of a high concentration of intracellular iron.

Resveratrol-Encapsulated Glutathione-Modified Robust Mesoporous Silica Nanoparticles as an Antibacterial and Antibiofilm Coating Agent for Medical Devices.

The emergence of various lethal bacterial infections and their adherence to medical devices are major public health concerns. The increased bacterial exposure and titer are accompanied by the inappropriate use of antibiotics that sometimes lead to antibiotic resistance, and therefore, a drug-free antibacterial approach is required. Several nanoparticles (NPs) have been developed as antibacterial and antibiofilm coating agents, which can overcome different drug resistance mechanisms by inhibiting the important processes related to bacterial virulence potential. However, developing safe and biocompatible nanomaterials (NMs) for these applications has remained a major challenge due to their poorly understood mechanism of action. In this work, biogenic silica NPs were modified with glutathione (GSH) to form GSH@SNP (∼80 ± 15 nm) for targeting the bacterial cell surface and biofilm. GSH@SNP was loaded with resveratrol to obtain Res_GSH@SNP (∼124 ± 15 nm) that enhances the antibacterial activity of the NPs against Staphylococcus aureus and Escherichia coli by ∼51 and ∼49%, respectively, compared to GSH@SNP. Res_GSH@SNP is responsible for binding to the bacterial cell surface receptors that interrupt the cell membrane potential, leading to reactive oxygen species (ROS) generation, membrane disruption, and DNA damage and eventually resulting in antibacterial activity. Moreover, the antibiofilm activity of Res_GSH@SNP has been found to result from the interaction of the NPs with the abundant carbohydrates present on the biofilm surface. To check the practical utility of Res_GSH@SNP, these were further evaluated as an antibacterial and antibiofilm coating agent for urinary catheters and were found to be effective even after multiple washes. Res_GSH@SNP has been found to exhibit ∼80 ± 1.4% cytocompatibility toward fibroblast NIH-3T3 cells. Overall, this study is expected to pave the way for the development of biocompatible NP-based coating agents for medical devices.