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Biology subjects

Mittra, I.

Publications and source records attributed to Mittra, I..

3 recordsLinked to original sources

A pro-oxidant combination of resveratrol and copper down-regulates multiple biological hallmarks of ageing and neurodegeneration

Several hundred billion to a trillion cells die in the body every day, and cell-free chromatin particles (cfChPs) that are released from them enter into the extracellular compartments of the body, including into the circulation. We have earlier reported that cfChPs can readily enter into healthy cells to damage their DNA, activate apoptotic pathways and induce inflammatory cytokines. We hypothesized that repeated lifelong assault on healthy cells by cfChPs is the underlying cause of ageing, and that the ageing process could be retarded by deactivating cfChPs. The latter can be effected by oxygen radicals that are generated upon admixing the nutraceuticals resveratrol (R) and copper (Cu). Using confocal microscopy and antibodies against DNA and histone we detected copious presence of extra-cellular cfChPs in brain of ageing mice, and observed that these were deactivated / eradicated following prolong oral administration of small quantities of R-Cu. Deactivation / eradication of cfChPs was associated with down-regulation of several biological hallmarks of ageing in brain cells which included reduction in: 1) telomere attrition, 2) amyloid deposition, 3) DNA damage, 4) apoptosis, 5) inflammation, 6) senescence, 7) aneuploidy and 8) mitochondrial dysfunction. At a systemic level, R- Cu treatment led to significant reduction in blood levels of glucose, cholesterol and C-reactive protein. These results suggest that cfChPs may be global instigators of ageing and neurodegeneration, and that therapeutic use of R-Cu may help to retard the process of ageing.

neuroscience↗

Cell-free chromatin particles released from dying cells inflict mitochondrial damage and ROS production in living cells

mtDNA damage and the resultant oxidative stress are associated with neurodegenerative diseases, ageing and cancer. However, what triggers mtDNA damage remains unclear. We have reported that cell-free chromatin particles (cfChPs) that are released from the billions of cells that die in the body every day can readily enter into healthy cells and damage their DNA. We show here that cfChPs isolated from sera of healthy individuals, or those that are released from dying cells, inflict direct physical damage mtDNA leading to marked activation of ROS. The latter could be abrogated by concurrent treatment with three different cfChPs deactivating agents. Given that 1x109-1x1012 cells die in the body every day, our findings suggest that cfChPs from dying cells are major physiological triggers for mtDNA damage and ROS production. Deactivation of cfChPs may provide a novel therapeutic approach to retard ageing and associated degenerative conditions that have been linked to oxidative stress.

biochemistry↗

Structural and energetic profiling of SARS-CoV-2 antibody recognition and the impact of circulating variants

The SARS-CoV-2 pandemic highlights the need for a detailed molecular understanding of protective antibody responses. This is underscored by the emergence and spread of SARS-CoV-2 variants, including B.1.1.7, P1, and B.1.351, some of which appear to be less effectively targeted by current monoclonal antibodies and vaccines. Here we report a high resolution and comprehensive map of antibody recognition of the SARS-CoV-2 spike receptor binding domain (RBD), which is the target of most neutralizing antibodies, using computational structural analysis. With a dataset of nonredundant experimentally determined antibody-RBD structures, we classified antibodies by RBD residue binding determinants using unsupervised clustering. We also identified the energetic and conservation features of epitope residues and assessed the capacity of viral variant mutations to disrupt antibody recognition, revealing sets of antibodies predicted to effectively target recently described viral variants. This detailed structure-based reference of antibody RBD recognition signatures can inform therapeutic and vaccine design strategies.

microbiology↗