Browsing by Author "Pooja Rai"

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Anti-diabetic drug pioglitazone reduces Islet amyloid aggregation overload in the Drosophila neuronal cells
(Springer Science and Business Media Deutschland GmbH, 2024) Khushboo Sharma; Pooja Rai; Shashank Kumar Maurya; Madhu G. Tapadia
Amyloid-proteinopathy is observed in type 2 diabetes, where Islet amyloid polypeptide is secreted atypically and impedes cellular homeostasis. The thiazolidinediones family is reported to influence amyloid-beta aggregations. However, research on drug-based stimulation of insulin signaling to alleviate Islet amyloid aggregations is lacking. To understand the impact of pioglitazone on islet amyloid aggregation, we conducted an in vivo and in silico analysis. For in vivo analysis, we generated a transgenic Drosophila harboring the preproform of human Islet amyloid polypeptide (IAPP) that can be ectopically expressed in a spatio-temporal manner. We show that the unprocessed form of IAPP also has the propensity to form aggregates and cause degeneration. Pioglitazone feeding effectively reduces the burden of Islet amyloid aggregations in the larval brain. In silico analysis shows that there is a higher protein–ligand binding energy for IAPP with pioglitazone than amyloid-beta. These results suggests that pioglitazone might be repurposed as a drug to cure islet amyloidogenesis. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Anti-diabetic drug pioglitazone reduces Islet amyloid aggregation overload in the Drosophila neuronal cells
(Springer Science and Business Media Deutschland GmbH, 2025) Khushboo Sharma; Pooja Rai; Shashank Kumar Maurya; Madhu Gwaldas Tapadia
Amyloid-proteinopathy is observed in type 2 diabetes, where Islet amyloid polypeptide is secreted atypically and impedes cellular homeostasis. The thiazolidinediones family is reported to influence amyloid-beta aggregations. However, research on drug-based stimulation of insulin signaling to alleviate Islet amyloid aggregations is lacking. To understand the impact of pioglitazone on islet amyloid aggregation, we conducted an in vivo and in silico analysis. For in vivo analysis, we generated a transgenic Drosophila harboring the preproform of human Islet amyloid polypeptide (IAPP) that can be ectopically expressed in a spatio-temporal manner. We show that the unprocessed form of IAPP also has the propensity to form aggregates and cause degeneration. Pioglitazone feeding effectively reduces the burden of Islet amyloid aggregations in the larval brain. In silico analysis shows that there is a higher protein–ligand binding energy for IAPP with pioglitazone than amyloid-beta. These results suggests that pioglitazone might be repurposed as a drug to cure islet amyloidogenesis. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Conformational Dynamics of Hsp90 and Hsp70 Chaperones in Treating Neurodegenerative Diseases: Insights from the Drosophila Model
(Springer Nature, 2024) Pooja Rai
Protein aggregates of misfolded proteins are a pathological hallmark of nearly all neurological disorders, including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and various polyglutamine diseases such as Huntington’s disease. Selective distribution in different cellular compartments highlights their core functions in cellular homeostasis. Investigating the cellular protein quality control system has become a significant strategy for counteracting protein aggregates and their toxic consequences. Heat shock proteins (Hsps) are crucial in regulating protein quality control, contributing to both protein aggregation and disaggregation. Beyond their well-known role in oncogenesis, several studies have identified Hsp90 as a key regulator of the functional stability of neuronal proteins. Similarly, Hsp70 is believed to promote cell survival by interacting with components of apoptotic and pro-survival pathways in neurodegeneration. Thus, targeting Hsp90 and Hsp70 represents a promising therapeutic strategy for treating neurodegenerative disorders. This review provides a comprehensive overview of the structure, mode of action, and roles of Hsp90 and Hsp70. Additionally, Drosophila melanogaster is highlighted as an effective model system for studying the roles of Hsp70 and Hsp90 in the proteinopathies associated with neurodegenerative diseases. © Indian National Science Academy 2024.
Development and Characterization of Zn(98−x).Mg2.(SiC)x Composites Synthesized in Graphite Packed Non-oxidizing Media
(Springer, 2021) Amrendra Rai; Pooja Rai; Vijay Kumar; Naresh Kumar Singh; Vinay Kumar Singh
Zinc-based composites have diverse areas of applications; in this context, Zn-Mg-based composite Zn(98−x).Mg2.(SiC)x (x = 0, 2, 4, 6 and 8 wt.%) was synthesized by sintering in non-oxidizing graphite packed media, which can be used as a degradable orthopedic implant. The assessment of mechanical properties, corrosion behavior and localized discharge of zinc ions in simulated body fluid after a certain interval of time was done. The results acquired from various investigations reveal that the composite with Zn92.Mg2.(SiC)6 has a maximum compressive strength of 106 MPa, flexural strength 92 MPa, hardness 55.48 VHN and Young’s modulus 50.353 GPa. The strengthening of the composites was enhanced because of the strain hardening effect of the reinforced SiC particles, which hinders the movement of the dislocations. Surface characteristics and phases evolved in the composite were analyzed by SEM and XRD Technique. © 2021, ASM International.
Effect of Sintering Temperature on the Physico-Mechanical Behavior of SiC Reinforced Zinc-Magnesium Based Composite
(Korean Institute of Metals and Materials, 2021) Amrendra Rai; Pooja Rai; Vijay Kumar; Naresh Kumar Singh; Vinay Kumar Singh
Abstract: The present research work deals with study the effect of sintering temperature on the physical and mechanical behavior of Zn2Mg6SiC composite, which can be used as a biodegradable implant. Sintering of the composite has been done at a temperature of 430 °C, 450 °C, 470 °C and 490 °C. The mechanical and physical properties of the samples have been observed to vary with sintering temperature. The grain size of the samples has observed to be optimized at 450 °C with grain size 0.2587 µm and provides maximum strength to the samples. The densification of the composites achieved was found to be maximum at 450 °C having a value 90.30%. Wear rate, hardness, Young’s Modulus of elasticity and flexural strength were observed to be maximum at this temperature. Scanning electron microscopy and X-ray diffraction spectroscopy of the samples at various temperatures were done to find microstructural changes and surface morphology of the composite. Graphic Abstract: [Figure not available: see fulltext.]. © 2020, The Korean Institute of Metals and Materials.
Endosomal recycling protein Rab11 in Parkin and Pink1 signaling in Drosophila model of Parkinson's disease
(Elsevier Inc., 2022) Pooja Rai; Jagat Kumar Roy
Neurodegenerative diseases are progressive disorders of the nervous system primarily affecting the loss of neuronal cells present in the brain. Although most neurodegenerative cases are sporadic, some familial genes are found to be involved in the neurodegenerative diseases. The extensively studied parkin and pink1 gene products are known to be involved in the removal of damaged mitochondria via autophagy (mitophagy), a quality control process. If the function of any of these genes is somehow disrupted, accumulation of damaged mitochondria occurs in the forms of protein aggregates in the cytoplasm, leading to formation of the Lewy-bodies. Autophagy is an important catabolic process where the endosomal Rab proteins are seen to be involved. Rab11, an endosomal recycling protein, serves as an ATG9A carrier that helps in autophagosome formation and maturation. Earlier studies have reported that loss of Rab11 prevents the fusion of autophagosomes with the late endosomes hampering the autophagy pathway resulting in apoptosis of cells. In this study, we have emphasized on the importance and functional role of Rab11 in the molecular pathway of Parkin/Pink1 in Parkinson's disease. © 2022
Exploring the therapeutic potential of Rab11: A comprehensive study on its effectiveness in alleviating rotenone-induced molecular pathogenesis of Parkinson's disease in SH-SY5Y cells and its synergistic application with L-DOPA in Drosophila models
(Elsevier B.V., 2024) Pooja Rai; Sada Nand Pandey; Jagat Kumar Roy
Dysfunctional mitophagy contributes to Parkinson's disease (PD) by affecting dopamine-producing neurons. Mutations in parkin and pink1 genes, linked to familial PD, impede the removal of damaged mitochondria. Previous studies suggested Rab11's involvement in mitophagy alongside Parkin and Pink1. Additionally, mitochondria-endoplasmic reticulum contact sites (MERCS) regulate cellular functions, including mitochondrial quality control and calcium regulation. Our study explored whether activating mitophagy triggers the unfolded protein response and ER stress pathway in SH-SY5Y human cells. We induced a PD-like state by exposing undifferentiated SH-SY5Y cells to rotenone, an established PD-inducing agent. This led to reduced Rab11 and PERK- expression while increasing ATP5a, a mitochondrial marker, when Rab11 was overexpressed. Our findings suggest that enhancing endosomal trafficking can mitigate ER stress by regulating mitochondria, rescuing cells from apoptosis. Furthermore, we assessed the therapeutic potential of Rab11, both alone and in combination with L-Dopa, in a Drosophila PD model. In summary, our research underscores the role of mitophagy dysfunction in PD pathogenesis, highlighting Rab11's importance in alleviating ER stress and preserving mitochondrial function. It also provides insights into potential PD management strategies, including the synergistic use of Rab11 and L-Dopa. © 2024
H50Q mutation in alpha-Synuclein impairs the insulin signaling pathway and induces neuroinflammation in the Drosophila model
(Elsevier Inc., 2025) Pooja Rai; Rakesh Kumar
H50Q mutations in the SNCA gene, also known as also known as the alpha-Synuclein (α-Syn), have been causally linked to familial Parkinson's disease (PD). PD is primarily characterized by the progressive loss of dopaminergic neurons in the substantia nigra region of the brain.α-Syn- plays a pivotal role in the formation of Lewy bodies (LB), a prominent pathological marker in PD. Growing evidence has highlighted the involvement of the insulin signaling pathway dysfunction in various neurodegenerative models. This study aimed to explore how the H50Q mutation in α-Syn influences the insulin signaling pathway and the overall lifespan of fruit flies afflicted with PD. It has been established that a mutation in α-Syn affects mitochondrial function and increases oxidative stress, ultimately contributing to the death of dopaminergic neurons. The impairment of mitochondrial function disrupts metabolism and exerts an adverse effect on the insulin signaling pathway. Furthermore, the unfolded protein response of the endoplasmic reticulum (ER) are investigated and observed a decrease in the expression of PERK (Protein kinase R-like ER kinase) during ER stress. These findings confirm the intricate interplay between the insulin signaling pathway and the activation of the PERK-ER stress pathway. However, the degeneration of neurons triggers a neuroinflammatory response, which are found to be mitigated by the improvement of insulin signaling and the PERK-ER stress-related pathway. The results of this studyshed light on the novel regulatory role of PERK within the insulin signaling pathway and suggest its potential as a therapeutic candidate for modulating neuroinflammation in the context of α-Syn -associated PD pathology. © 2025 Elsevier Inc.
Impaired insulin signaling and diet-induced type 3 diabetes pathophysiology increase amyloid β expression in the Drosophila model of Alzheimer's disease
(Elsevier B.V., 2025) Khushboo Sharma; Pooja Rai; Madhu Gwaldas Tapadia
Compelling evidence has strongly linked unregulated sugar levels to developing Alzheimer's disease, suggesting Alzheimer's to be ‘diabetes of the brain or ‘type 3 diabetes. Insulin resistance contributes to the pathogenesis of Alzheimer's disease due to uncontrolled and unchecked blood glucose, though the interrelatedness between Alzheimer's disease and type 2 diabetes is debatable. Here we describe the consequences of inducing type 3 diabetes by feeding Drosophila on a high sucrose diet, which effectively mimics the pathophysiology of diabetes. A high sucrose diet increases glycogen and lipid accumulation. Inducing type 3 diabetes worsened neurodegeneration and accelerated disease progression in Drosophila expressing the Alzheimer's Familial Arctic mutation. High sucrose milieu also negatively affected locomotor ability and reduced the lifespan in the Alzheimer's disease model of Drosophila. The results showed that creating diabetic conditions by using insulin receptor (InR) knockdown in the eyes of Drosophila led to a degenerative phenotype, indicating a genetic interaction between the insulin signaling pathway and Alzheimer's disease. The expression of PERK reflects disruption in the endoplasmic reticulum homeostasis due to amyloid-β (Aβ) under a high sucrose diet. These observations demonstrated an association between type 3 diabetes and Alzheimer's disease, and that a high sucrose environment has a degenerating effect on Alzheimer's disease condition. © 2024 Elsevier B.V.
Rab11 regulates mitophagy signaling pathway of Parkin and Pink1 in the Drosophila model of Parkinson's disease
(Elsevier B.V., 2022) Pooja Rai; Jagat Kumar Roy
Parkinson's disease (PD) is a common neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra. The pathophysiology of this disease is the formation of the Lewy body, mostly consisting of alpha-synuclein and dysfunctional mitochondria. There are two common PD-associated genes, Pink1 (encoding a mitochondrial ser/thr kinase) and Parkin (encoding cytosolic E3-ubiquitin ligase), involved in the mitochondrial quality control pathway. They assist in removing damaged mitochondria via selective autophagy (mitophagy) which if unchecked, results in the formation of protein aggregates in the cytoplasm. The role of Rab11, a small Ras-like GTPase associated with recycling endosomes, in PD is still unclear. In the present study, we used the PD model of Drosophila melanogaster and found that Rab11 has a crucial role in the regulation of mitochondrial quality control and endo-lysosomal pathways in association with Parkin and Pink1 and Rab11 acting downstream of Parkin. Additionally, overexpression of Rab11 in parkin mutant rescued the mitochondrial impairment, suggesting the therapeutic potential of Rab11 in PD pathogenesis. © 2022 Elsevier Inc.
Rab11 rescues muscle degeneration and synaptic morphology in the park13/+ Parkinson model of Drosophila melanogaster
(Elsevier B.V., 2023) Pooja Rai; Anuradha Ratnaparkhi; Jagat Kumar Roy
Mutation in parkin and pink1 is associated with Parkinson's disease (PD), the most common movement disorder characterized by muscular dysfunction. In a previous study, we observed that Rab11, a member of the small Ras GTPase family, regulates the mitophagy pathway mediated by Parkin and Pink1 in the larval brain of the Drosophila PD model. Here, we describe that the expression and interaction of Rab11 in the PD model of Drosophila is highly conserved across different phylogenic groups. The loss of function in these two proteins, i.e., Parkin and Pink1, leads to mitochondrial aggregation. Rab11 loss of function results in muscle degeneration, movement disorder and synaptic morphological defects. We report that overexpression of Rab11 in park13 heterozygous mutant improves muscle and synaptic organization by reducing mitochondrial aggregations and improving cytoskeleton structural organization. We also show the functional relationship between Rab11 and Brp, a pre-synaptic scaffolding protein, required for synaptic neurotransmission. Using park13 heterozygous mutant and pink1RNAi lines, we showed reduced expression of Brp and consequently, there were synaptic dysfunctions including impaired synaptic transmission, decreased bouton size, increase in the bouton numbers, and the length of axonal innervations at the larval neuromuscular junction (NMJ). These synaptic alterations were rescued with the over-expression of Rab11 in the park13 heterozygous mutants. In conclusion, this work emphasizes the importance of Rab11 in rescuing muscle degeneration, movement dysfunction and synaptic morphology by preserving mitochondrial function in the PD model of Drosophila. © 2023 Elsevier B.V.
Role of heat shock proteins in oncogenesis and strategy for treating cancers using Drosophila model
(Springer Nature, 2023) Pooja Rai
A cluster of closely stored molecules that are engaged in different cellular processes is the mammalian HSP90 protein family. HSP90 works with HSP70 but is not dependent on the cochaperone of HSP90. HSPs are molecular chaperones required to fold, stabilize, and degrade proteins that are responsible for multiple tumor types. Hence targeting HSP90 and HSP70 presents a striking strategy for treating cancers. The present review article provides an overview of the structure, mode of action as well as role of HSP90 and HSP70. They are part of key regulatory processes that directly influence oncogenic pathways. As Drosophila melanogaster acts as an appropriate model system for research studies involving the above-stated disorders, emphasis has been put on summarizing some of the research studies in oncogenesis. © 2023, Indian National Science Academy.
Study of mechanical, electrochemical, cellular and antibacterial response of Zn2Mg6SiC biodegradable implant
(Elsevier Ltd, 2020) Amrendra Rai; Pooja Rai; Vijay Kumar; Naresh Kumar Singh; Vinay Kumar Singh
The present work focuses on the development of a load-bearing biodegradable implant that can apply to repair fractured bones. A novel composite Zn2Mg6SiC was developed via powder metallurgy route and its mechanical, electrochemical and biological properties were studied. A biodegradable implant is imperative to have adequate mechanical strength, better corrosion properties and sufficient biocompatibility. Also, it is expected to sustain its strength until bone healing. In this context, the present work analyses the variation of mechanical properties of Zn2Mg6SiC composite with immersion in SBF for different time durations. Flexural strength, compressive strength, hardness and young's modulus of the composite were sufficient during the immersion period. The corrosion rate of Zn2Mg6SiC depicted from potentiodynamic polarisation was between the ranges of 0.0250 mm/year to 0.0291 mm/year. The Cell cytotoxicity analysis of the composite, performed on osteoblast-like MG-63 cells cultured in incubation media has shown its biocompatibility. Antibacterial tests of the samples were performed for both S. aureus and E. coli bacterias. Results obtained from biological testing have supported the application of the Zn2Mg6SiC composite as a biocompatible implant. SEM, EDS and XRD of the composite in SBF were done to find microstructural changes and elemental concentrations in the composite. © 2020 Elsevier Ltd and Techna Group S.r.l.