Biology subjects

Anand, T.

Publications and source records attributed to Anand, T..

9 recordsLinked to original sources

bioRxiv2025

Hydrogel microdroplet based glioblastoma drug screening platform

Glioblastoma is the most common primary malignant brain tumor with a five-year survival rate less than 5%. The standard of care involves surgical resection followed by treatment with the alkylating agent temozolomide (TMZ). GBM cells that evade surgery eventually become resistant to TMZ and lead to recurrence of tumors in patients. With only four drugs currently FDA-approved for GBM treatment, there is a need for a clinically relevant model capable of accelerating the identification of new therapies. Microgels are microscale ([~]10-1,000 m) hydrogel particles that can be used to encapsulate cells in a tailorable 3D matrix. Microdroplets offer short diffusion lengths relative to conventional hydrogel constructs (>1 mm) to limit spatial distributions of hypoxia and potentially screen therapeutics in a controlled and physiologically relevant environment. Here, we establish a method to encapsulate GBM cells in gelatin and polyethylene glycol (PEG) microgels. We show that microgel composition can affect cell morphology and further, that collections of GBM-laden hydrogels can be used to quantify the effect of single vs. metronomic doses of TMZ. GBM metabolic activity is maintained in microgel culture and GBM cells display drug response kinetics similar to previously established literature using macro-scale hydrogel constructs. Finally, we show microgels can be integrated with a liquid handler to enable high-throughput screening using cell-laden microgels.

bioengineering↗

bioRxiv2025

Molecular insights into electroreceptor ribbon synapses from differential gene expression in sturgeon lateral line organs

In fishes and aquatic-stage amphibians, mechanosensory neuromasts are arranged in characteristic lines in the skin of the head and trunk, with afferent innervation from anterior or posterior lateral line nerves. In electroreceptive non-teleost jawed fishes and amphibians, fields of electrosensory ampullary organs flank some or all of the cranial neuromast lines, innervated by the anterior lateral line nerve. Like the mechanosensory hair cells found in neuromasts and the inner ear, electroreceptor cells in ampullary organs form specialised ribbon synapses with afferent nerve terminals. Ribbon synapses in hair cells are distinct from other glutamatergic synapses, including the ribbon synapses in photoreceptors: otoferlin is the Ca2+ sensor for synaptic vesicle exocytosis and synaptic vesicles are loaded with glutamate by vGlut3. We previously showed that the genes encoding otoferlin and vGlut3 are expressed by ampullary organs as well as neuromasts in a chondrostean ray-finned fish, the Mississippi paddlefish (Polyodon spathula), suggesting that electroreceptor ribbon synapses are very similar to those in hair cells. In this study, we selected seven additional synapse-related candidate genes from our previously published dataset of putatively lateral line organ-enriched genes from late-larval paddlefish, and examined their expression in developing lateral line organs in a related chondrostean, the sterlet sturgeon (Acipenser ruthenus). We found that genes encoding the presynaptic cell adhesion molecule Nrxn3, the calcium-independent synaptotagmin Syt14, the high-affinity glutamate re-uptake transporter EAAT1 (GLAST), calmodulin regulator protein PCP4 (PEP-19) and cell adhesion molecule DSCAML1 were expressed in both neuromasts and ampullary organs. In contrast, Cbln18, encoding a secreted trans-synaptic scaffolding protein, was only expressed in neuromasts and Tulp1, encoding tubby-related protein 1 (required for the development and function of photoreceptor ribbon synapses), was only expressed in ampullary organs. Our results support electroreceptor ribbon synapses being glutamatergic and suggest further commonalities, but also some differences, with hair cell ribbon synapses.

developmental biology↗

bioRxiv2024

AyurPhenoClusters define common molecular roots for rare diseases and uncover ciliary dysfunctions in syndromic conditions

The heterogeneity of underlying causes and the variability of symptoms across Multiple organs in rare diseases present significant challenges when approached from an organ-centric perspective. Ayurveda, however, takes a multisystem perspective, assessing diseases through kinetic (Vata:V ), metabolic (Pitta:P ), and structural (Kapha:K ) dimensions, each with distinct phenotypic and molecular correlates. This study explores rare diseases from a systems perspective by integrating Ayurveda and unifying terminologies from both disciplines using Human Phenotype Ontology (HPO). Experts categorized 10,610 HPO terms into Ayurvedic phenotypic groups (V/P/K ) and applied the Expectation Maximization (EM) algorithm to cluster 12,678 diseases. This yielded six distinct clusters, termed AyurPhenoClusters, with 2,814 diseases uniquely classified and enriched for V/P/K phenotypes. Functional annotation of these, highlighted key biological processes: (i) embryogenesis and skeletal morphogenesis, (ii) endocrine and ciliary functions, (iii) DNA damage response and cell cycle regulation, (iv) inflammation and immune response, (v) immune function, hemopoiesis, and telomere aging, and (vi) small molecule metabolism and transport. Notably, the K predominant cluster had the highest ciliary gene enrichment (43%), followed by the V predominant cluster (16%), suggesting potential ciliopathies in V cluster. This systems-based approach enhances the understanding of rare diseases by bridging Ayurveda with modern medicine, for improved diagnostics and therapeutics

genetics↗

bioRxiv2023

Neutralization Escape by SARS-CoV-2 Omicron Subvariant BA.2.86

The continued evolution of SARS-CoV-2 may lead to evasion of vaccine immunity and natural immunity. A highly mutated Omicron variant BA.2.86 has recently been identified with over 30 amino acid changes in Spike compared with BA.2 and XBB.1.5. As of September 4, 2023, BA.2.86 has been identified in 37 sequences from 10 countries, which is likely an underestimate due to limited surveillance. The ability of BA.2.86 to evade NAbs compared with other currently circulating Omicron variants remains unknown. Our data show that NAb responses to BA.2.86 were lower than to BA.2 but were comparable or slightly higher than to the current circulating recombinant variants XBB.1.5, XBB.1.16, EG.5, EG.5.1, and FL.1.5.1.

microbiology↗

bioRxiv2023

Waning Immunity Against XBB.1.5 Following Bivalent mRNA Boosters

The SARS-CoV-2 Omicron variant has continued to evolve. XBB is a recombinant between two BA.2 sublineages, XBB.1 includes the G252V mutation, and XBB.1.5 includes the G252V and F486P mutations. XBB.1.5 has rapidly increased in frequency and has become the dominant virus in New England. The bivalent mRNA vaccine boosters have been shown to increase neutralizing antibody (NAb) titers to multiple variants, but the durability of these responses remains to be determined. We assessed humoral and cellular immune responses in 30 participants who received the bivalent mRNA boosters and performed assays at baseline prior to boosting, at week 3 after boosting, and at month 3 after boosting. Our data demonstrate that XBB.1.5 substantially escapes NAb responses but not T cell responses after bivalent mRNA boosting. NAb titers to XBB.1 and XBB.1.5 were similar, suggesting that the F486P mutation confers greater transmissibility but not increased immune escape. By month 3, NAb titers to XBB.1 and XBB.1.5 declined essentially to baseline levels prior to boosting, while NAb titers to other variants declined less strikingly.

immunology↗

bioRxiv2022

Folic acid-loaded chitosan nanoparticles: Cytotoxicity, acute and sub-acute oral toxicity and bioavailability in Wistar rats

The study aims to develop folic acid-loaded chitosan nanoparticles (FA-Chi-NPs) as the vitamin is sensitive to heat and light and to investigate the safety of FA-Chi-NPs in vitro and in vivo. The prepared formulation showed an average diameter of 191.7 {+/-} 2 nm with a zeta potential of + 52 {+/-} 4 mV and PDI of 0.195 {+/-} 0.03. The encapsulation efficiency was found to be 80%. In vitro cytotoxicity assays revealed that FA-Chi-NPs had no cytotoxic effect on Caco-2 cells. Acute-toxicity and subacute-toxicity of FA-Chi-NPs (0.4, 2, and 4 mg/kg body weight) revealed no mortality, and no gross morphological abnormalities were noticed. There were no dose-dependent toxic effects of free folic acid (FA) and FA-Chi-NPs in haematological, histological, plasma biochemical indices, oxidative stress enzymes, or other parameters when compared to the control group(s). The plasma and tissue levels of FA from FA-Chi-NPs were significantly higher. Results demonstrated enhanced bioavailability of FA from FA-Chi-NPs with no toxicity. Practical applicationsIn the current study, nanoencapsulation is used as a potential approach to enhance folic acid bioavailability. The results showed that encapsulating folic acid in chitosan improved bioavailability with no apparent adverse effects, and thus chitosan could be a promising polymer for safe folic acid delivery.

pharmacology and toxicology↗

bioRxiv2022

E2 ubiquitin conjugase Bendless is essential for PINK1-Park activity to regulate Mitofusin under mitochondrial stress

Cells under mitochondrial stress often co-opt mechanisms to maintain energy homeostasis, mitochondrial quality control and cell survival. A mechanistic understanding of such responses is crucial for further insight into mitochondrial biology and diseases. Through an unbiased genetic screen in Drosophila, we identify that mutations in lrpprc2, a homolog of the human LRPPRC gene that is linked to the French-Canadian Leigh syndrome, results in PINK1-Park activation. While the PINK1-Park pathway is well known to induce mitophagy, we show that in the case of lrpprc2 mutants, PINK1-Park regulates mitochondrial dynamics by inducing degradation of the mitochondrial fusion protein Mitofusin/Marf. We also discover that Bendless, a K63-linked E2 conjugase, is a regulator of Marf, as loss of bendless results in increased Marf levels. We show that Bendless is required for PINK1 stability, and subsequently for PINK1-Park mediated Marf degradation under physiological conditions, and in response to mitochondrial stress as seen in lrpprc2. Additionally, we show that loss of Bendless in lrpprc2 mutant eye results in photoreceptor degeneration, indicating a neuroprotective role for Bendless-PINK1-Park mediated Marf degradation. Based on our observations, we propose that certain forms of mitochondrial stress activate Bendless-PINK1-Park to limit mitochondrial fusion, which is a cell-protective response.

genetics↗

bioRxiv2021

Reduced Lytic Activity of Bacteriophages in Presence of Antibiotics Targeting Bacterial Protein Synthesis

Combination therapy of bacteriophage and antibiotics offers promise to treat multiple drug resistant bacterial infections through phage antibiotic synergy. However, its usage requires careful assessment as most antibiotics with mechanisms dependent upon inhibiting cell growth through interfering bacterial protein synthesis machinery were found to have an antagonistic effect on phage activity.

microbiology↗

bioRxiv2020

Resolving mechanisms of immune-mediated disease in primary CD4 T cells

Deriving mechanisms of immune-mediated disease from GWAS data remains a formidable challenge, with attempts to identify causal variants being frequently hampered by linkage disequilibrium. To determine whether causal variants could be identified via their functional effects, we adapted a massively-parallel reporter assay for use in primary CD4 T-cells, key effectors of many immune-mediated diseases. Using the results to guide further study, we provide a generalisable framework for resolving disease mechanisms from non-coding associations - illustrated by a locus linked to 6 immune-mediated diseases, where the lead functional variant causally disrupts a super-enhancer within an NF-{kappa}B-driven regulatory circuit, triggering unrestrained T-cell activation.

genetics↗