Biology subjects

Nongthomba, U.

Publications and source records attributed to Nongthomba, U..

10 recordsLinked to original sources

bioRxiv2026

Bio-Templated Zinc Oxide Nanotherapeutics from Flemingia macrophylla kuntze Ex Merr: In Vivo Anti-Diabetic and Anti-Inflammatory Efficacy in Drosophila melanogaster

Nanotechnology has a major impact on the creation of novel and effective therapies for the treatment of several diseases, including diabetes and cancer. The current work is a report on the use of the aqueous extract from the leaves of the Flemingia macrophylla plant as a capping and reducing agent in the green synthesis of zinc oxide nanoparticles (ZnO-NPs).The synthesized ZnO-NPs were subjected to characterization through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy (UV-Vis). Dose-dependent in vivo effects were investigated using Drosophila melanogaster subjected to a high-sugar diet (HSD) to induce a diabetic-like model. In vitro anti-oxidant, anti-diabetic, anti-inflammatory assay, survival, locomotor function, neuroanatomical integrity, ovary and testis morphology, egg-laying capacity, and male fertility were evaluated. The most prominent UV-visible peak was detected at around 370 nm. Structural and morphological analysis via XRD and electron microscopy confirmed the hexagonal phase of the ZnO-NPs, indicating an average calcined particle size of around 47 nm at 500 degree C. The manuscript reports significant anti-diabetic and anti-inflammatory effects in vitro and in the in vivo Drosophila model, together with antioxidant activity. The in vivo results indicate that green-synthesized ZnO-NPs mitigate adverse phenotypes triggered by a high-sugar diet and also potential as an anti-diabetic intervention and warrant further mechanistic and preclinical investigation. Keywords: Flemingia macrophylla; Green ZnO-NPs; Drosophila melanogaster; high-sugar diet; nanobiotechnology

pharmacology and toxicology↗

bioRxiv2026

Polyisobutylene Micro/Nanoplastics Induce Multi-System Toxicity, Intestinal Barrier Dysfunction, and Neurodegeneration in Drosophila melanogaster

Micro/nanoplastics (MNPs) are increasingly recognized as a persistent environmental contaminant of concern, yet polyisobutylene (PIB), an industrially significant polymer used as industrial sealants, adhesives, cable insulation, lubricant additives, and chewing gum bases, remains poorly studied relative to more commonly studied plastics such as polyethylene terephthalate (PET), polystyrene (PS), and polyethylene (PE). This study investigated the multisystem toxicological effects of chronic dietary exposure to PIB-MNPs in Drosophila melanogaster. PIB-MNPs (> 5 micron) were synthesized via the solvent evaporation method and characterized using scanning electron microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR), confirming successful synthesis. Flies were chronically exposed to PIB-MNPs (1, 2, or 3 mg) alongside an SDS control and a water control to 50 mg of yeast over 21 days, with toxicological outcomes assessed via survival analysis, climbing assays, fluorescence brain imaging, fertility/fecundity assays, the Smurf gut-permeability assay, Ellman's AChE activity assay, and RT-qPCR analysis of Stat92E expression, a marker of inflammation. Chronic exposure to PIB-MNPs reduced survival, with females exhibiting markedly greater susceptibility than males. Exposure progressively impaired locomotor performance and induced brain vacuolization suggestive of neurodegeneration, peaking at day 15. AChE activity declined in a concentration-dependent manner by day 21. Female fecundity, egg-hatching rate, and ovarian egg-chamber maturation were significantly reduced, while male gonadal cyst cell numbers remained largely unaffected. PIB-MNPs exposure also induced a positive Smurf phenotype, indicating compromised intestinal barrier integrity and upregulated Stat92E expression, consistent with activation of a systemic stress response. Notably, several endpoints showed non-monotonic, concentration-independent trends, suggesting particle aggregation may influence effective bioavailability. Collectively, these findings establish PIB-MNPs as a multi-system toxicant in Drosophila.

cell biology↗

bioRxiv2025

Beadex modulates hematopoiesis and innate immune defense against microbial infection in Drosophila melanogaster

Transcription factors play a crucial role during hematopoiesis with implications in leukemia. LIM-domain only proteins (LMO) are also found to be associated with chromosomal translocation in T-cell acute lymphoblastic leukemia and are highly expressed in acute myeloid leukemia, where they correlate with poor prognosis. However, their role in myeloid cell lineage specification and function is poorly understood. Using Drosophila melanogaster, which possesses a single LMO homolog, Beadex (dLMO), and a conserved myeloid-like immune system, we have shown its conserved role in plasmatocytes (equivalent to macrophages) development and innate immunity. Beadex is expressed in progenitor and differentiated plasmatocytes, and its loss reduced lymph gland size, mature plasmatocyte numbers and phagocytic efficiency. The phagocytes of Beadex mutant flies feature reduced filopodia length and lamellipodium area. Mechanistically, Beadex regulates actin remodelling by regulating the expression level of profilin (chickadee/chic), as chic overexpression rescued the defect in phagocytosis. Overexpression of Beadex in hemocytes increased fly susceptibility towards Salmonella enterica serovar Typhimurium infection and this mortality was due to an infection-induced pathology independent of bacterial burden. Bulk RNA sequencing of Beadex knockdown hemocytes revealed transcriptional changes in actin cytoskeleton regulatory genes, phagosome function and immune response pathways. In conclusion, our study identifies Beadex as a key transcriptional regulator impacting multiple aspects of myeloid cell function, ranging from hematopoiesis and cytoskeletal dynamics to host-level immune defense.

immunology↗

bioRxiv2024

The interplay between Zfh1 and Nau orchestrates the myogenic stage-dependent expression of Rbfox1 and its target Stat92E via a mir-9a-mediated negative feedback loop in Drosophila melanogaster

RNA-binding Fox protein 1 (Rbfox1) controls gene expression at various levels: as a transcription co-factor, a splicing factor, and a regulator of mRNA stability and translation. Rbfox1 and its vertebrate orthologues have critical functions during development. Rbfox1 mRNA, during adult myogenesis in Drosophila, exhibits bimodal expression, suggestive of the presence of a negative feedback loop. However, there are no known negative regulators of Rbfox1 expression for this context. In this study, we show that the microRNA mir-9a functions as a repressor of Rbfox1 expression. Furthermore, the expression of mir-9a is regulated by the expression of the identity transcription factor Nau. Nau and its target mir-9a are expressed at mid myogenesis stage, and serve to restrict the expression of Rbfox1, and its targets Stat92E and zfh1, to the early and the late myogenesis stages, as their ectopic expression is detrimental to early myofibrillogenesis. Zfh1, in turn, represses mir-9a expression, completing the feedback loop. Therefore, our findings identify the mechanism by which the temporal expression of the developmental gene Rbfox1 and its targets are tightly regulated, essential for their functions during myogenesis. Summary statementUsing Drosophila, we show that a microRNA-mediated negative feedback loop controls the expression of genes critical for skeletal muscle development.

developmental biology↗

bioRxiv2024

Rbfox1 and mir-33 regulate pleiotropic roles of JAK/STAT signalling during adult myogenesis in Drosophila melanogaster

The JAK/STAT pathway is a conserved metazoan signal transduction system with roles in regulating growth, stem cells, and immune responses. Although its components are ubiquitously expressed during development, JAK/STAT signalling exerts cell-specific effects through mechanisms largely unknown. Here, we demonstrate that cell-specific effects of JAK/STAT signalling could be realised through post-transcriptional regulation. We show that JAK/STAT signalling in early adult myogenesis is critical for the patterning of the dorsal longitudinal muscles in Drosophila melanogaster. RNA-binding Fox protein 1 (Rbfox1) and the microRNA mir-33 regulate the transcript stability of Signal-transducer and activator of transcription protein at 92E (Stat92E), which encodes the sole Drosophila STAT orthologue. Moreover, Rbfox1 also controls the alternative splicing of Stat92E and its key downstream effector, Zn finger homeodomain 1 (zfh1). The coupling of Rbfox1 with Stat92E function, during early adult myogenesis, not only allows maintenance of stemness, but also mediates filamentous actin dynamics, and prevents apoptosis in myoblasts via some other Stat92E target genes. Given that the functions of the JAK/STAT pathway in cell proliferation and survival are conserved between Drosophila and vertebrates, our report presents a novel example for the context-dependant regulation of the developmental role of an important signalling pathway.

developmental biology↗

bioRxiv2023

Bacterial pore-forming toxin pneumolysin drives pathogenicity through shed toxin-loaded host extracellular vesicles

Streptococcus pneumoniae is a global priority respiratory pathogen that kills over a million people annually and produces the pore-forming cytotoxin, pneumolysin (PLY). Host cells expel membrane assembled toxin by shedding microvesicles, but the composition and pathophysiological sequelae of the toxin-induced host extracellular vesicles (EVs) are unknown. Here, we found that EVs shed from PLY-challenged monocytes (PLY-EVs) harbor membrane-bound toxin that induced cytotoxicity upon fusion with recipient cells. EVs from human monocytes challenged with recombinant PLY as well as PLY-expressing pneumococcal strains, but not the isogenic PLY mutant, primed dendritic cells and evoked higher pro-inflammatory cytokines upon infection. Proteomic analysis revealed that PLY-EVs are enriched for key antimicrobial and inflammatory host proteins such as IFI16, NLRC4, PTX3 and MMP9. In vivo, zebrafish and mice administered with PLY-EVs showed mortality, pericardial edema, tissue damage and inflammation. Our findings show that host EVs bearing the cytotoxin PLY constitute a previously unexplored mechanism of pneumococcal pathogenesis.

microbiology↗

bioRxiv2023

Beadex, the Drosophila LIM only protein, is required for the growth of the larval neuromuscular junction and sensorimotor activities

The appropriate growth of the neurons, accurate organization of their synapses, and successful neurotransmission are indispensable for sensorimotor activities. These processes are highly dynamic and tightly regulated. Extensive genetic, molecular, physiological, and behavioural studies have identified many molecular players and investigated their roles in various neuromuscular processes. In this paper, we show that Beadex (Bx), the Drosophila LIM only (LMO) protein, is required for motor activities and neuromuscular growth of Drosophila. Bx7, a null allele, adult flies are flightless, with reduced walking and jumping activities. The larvae of Bx7, and the RNAi-mediated neuronal-specific knockdown of Bx show drastically reduced crawling behaviour, a diminished synaptic span of the neuromuscular junctions and an increased spontaneous neuronal firing with altered motor patterns in the central pattern generators (CPGs). Microarray studies identified multiple targets of Beadex that are involved in different cellular and molecular pathways, including those associated with the cytoskeleton and mitochondria, that could be responsible for the observed neuromuscular defects. With genetic interaction studies, we further show that Highwire (Hiw), a negative regulator of synaptic growth at the NMJs, negatively regulates Bx, as the latters deficiency was able to rescue the phenotype of the Hiw null mutant, HiwDN. Thus, our data indicates that Beadex functions downstream of Hiw to regulate the larval synaptic growth and physiology.

developmental biology↗

bioRxiv2021

Spatial and temporal requirement of Mlp60A isoforms during muscle development and function in Drosophila melanogaster

Many myofibrillar proteins undergo isoform switching in a spatio-temporal manner during muscle development. The biological significance of the variants of several of these myofibrillar proteins remains elusive. One such myofibrillar protein, the Muscle LIM Protein (MLP), is a vital component of the Z-discs. In this paper, we show that one of the Drosophila MLP encoding genes, Mlp60A, gives rise to two isoforms: a short (279 bp, 10 kDa) and a long (1461 bp, 54 kDa) one. The short isoform is expressed throughout development, but the long isoform is adult-specific, being the dominant of the two isoforms in the indirect flight muscles (IFMs). A concomitant, muscle-specific knockdown of both isoforms leads to late pupal lethality, with the surviving flies being majorly flight defective. Mlp60A null flies show developmental lethality, and muscle defects in the individuals surviving till the third instar larval stage. This lethality could be rescued partially by muscle-specific overexpression of the short isoform. Almost 90% of the long isoform-specific P-element insertion mutant flies show a compromised flight ability and have reduced sarcomere length. Hence, our data shows that the two Mlp60A isoforms are functionally specialized, to ensuring normal embryonic muscle development and adult flight muscle function.

developmental biology↗

bioRxiv2021

Rbfox1 is required for myofibril development and maintaining fiber-type specific isoform expression in Drosophila muscles

Protein isoform transitions confer distinct properties on muscle fibers and are regulated predominantly by differential transcription and alternative splicing. RNA-binding Fox protein 1 (Rbfox1) can affect both transcript levels and splicing, and is known to control skeletal muscle function. However, the detailed mechanisms by which Rbfox1 contributes to normal muscle development and physiology remain obscure. In this study, we report that Rbfox1 contributes to the generation of adult muscle diversity in Drosophila. Rbfox1 is differentially expressed in tubular and fibrillar muscle fiber types. RNAi knockdown of Rbfox1 leads to a loss of flight, climbing and jumping ability, as well as eclosion defects. Myofibers in knockdown muscle are frequently torn, and sarcomeres are hypercontracted. These defects arise from mis-regulation of fiber-type specific gene and splice isoform expression, notably loss of an IFM-specific isoform of Troponin-I that is critical for regulating myosin activity. We find that Rbfox1 influences mRNA transcript levels through 1) direct binding of 3-UTRs of target transcripts as well as 2) through regulation of myogenic transcription factors, including Mef2, Exd and Salm. Moreover, Rbfox1 modulates splice isoform expression through 1) direct regulation of target splice events in structural genes and 2) regulation of the CELF-family RNA-binding protein Bruno1. Our data indicate that cross-regulatory interactions observed between FOX and CELF family RNA-binding proteins in vertebrates are conserved between their counterparts, Rbfox1 and Bruno1 in flies. Rbfox1 thus affects muscle development by regulation of both fiber-type specific gene and gene isoform expression dynamics of identity genes and structural proteins.

developmental biology↗

bioRxiv2017

Knock down of Calcineurin-B2, a calcium binding regulatory subunit of Calcineurin, gives rise to hypercontraction myopathy in indirect flight muscles of Drosophila through dysregulation of calcium homeostasis

Abstract/SummaryMuscle is a calcium responsive tissue and requires calcium for initiation of muscle contraction. Calcium concentration in muscle is tightly regulated by calcium binding proteins. Calcineurin-B2 (canB2), a calcium binding, regulatory subunit of calcineurin, is the isoform maximally expressed in the indirect flight muscles (IFMs) of Drosophila. The developmental and functional roles of CanB2 particularly in the maintenance of calcium homeostasis are not understood. In this study, we show that the loss of canB2 causes hypercontraction of IFMs. Genetic interaction studies with hypercontraction mutants suggest a synergistic interaction between Calcineurin-B2 and structural protein Troponin-T. Similarly, interaction studies with dSERCA mutant reveal that Calcineurin-B2 is important for regulating calcium homeostasis in muscles. In vivo calcium imaging showed that Calcineurin-B2 deficiency leads to arrhythmicity in the calcium oscillations. We show that Calcineurin-B2 knockdown causes deregulation of calcium homeostasis, which results in unregulated acto-myosin interaction. However, overexpression of Calcineurin-A, which inhibits calcium oscillations, had no effect on myofibrillogenesis suggesting that calcium activation is dispensable for myofibrillar assembly. Our findings contribute to the understanding of muscle physiology in normal as well as pathophysiological conditions.

cell biology↗