Prajakta Deshpande - Academia.edu (original) (raw)

Papers by Prajakta Deshpande

Research Square (Research Square), Sep 21, 2020

Background: Morquio A syndrome (MPS IVA) is a mucopolysaccharide group storage disorder caused du... more Background: Morquio A syndrome (MPS IVA) is a mucopolysaccharide group storage disorder caused due to the de cient activity of the lysosomal enzyme N-acetylgalactoseamine-6-sulfatase encoded by GALNS. The present study represents the mutation spectrum of GALNS in 25 Gujarati Patel patients of India clinically and biochemically con rmed with Morquio-A disorder. Methods: Urinary GAG quantitation and leucocyte enzyme assay was carried out in all 25 patients. This was followed by molecular characterization by ampli cation and sequencing of the exons and adjacent intronic regions of GALNS gene. Haplotype analysis was performed in patients showing p.P77R variant, using microsatellite markers D16S3121, D16S3026 and D16S3023 and SNPs. Results: We identi ed 11 mutations that include eight missense mutations: (p.L36R, p.D39G, p.P77R, p.C79R, pP125L, p.P151L, p.G255A and p.L350P), one splice site mutation: (c.121-7C>G), one small insertion: (c.1241_1242insA, p.I416HfsTer2) and one small deletion: (c.839_41delACA). Of these, three missense mutations (p.D39G, p.G255A and p.L350P), one splice site and the two indels mentioned above are novel. In the present study, we found maximum number of mutant alleles in exon 2, and of note, the variant p.P77R was seen in fourteen patients. Conclusion: p.P77R variant was predominantly found in Gujarati Patel community and the results of haplotype analysis indicated it to be the founder mutation in this community. Further, a study of 200 unrelated healthy control participants from Gujarat has identi ed this mutation in the heterozygous status in two individuals. Overall, our study suggests that p.P77R is likely to be a founder mutation for Morquio-A syndrome in Gujarati Patel ethnicity.

Alzheimer's & Dementia

BackgroundOne of the hallmarks of Alzheimer’s disease (AD), an age‐related progressive form of de... more BackgroundOne of the hallmarks of Alzheimer’s disease (AD), an age‐related progressive form of dementia, is accumulation of the amyloid beta (Aβ42) plaque, which manifests in decline in cognitive function. The accumulation of these Aβ42 plaques trigger the hyperphosphorylation of tau, a microtubule associated protein, which results in the intracellular accumulation of neurofibrillary tangles (NFTs) due to destabilization of microtubules.MethodWe employed the Gal4/UAS system in Drosophila melanogaster to misexpress human Aβ42 within the developing fly retina, exhibiting AD‐like neuropathology. Accumulation of Aβ42 plaque(s) triggers the aberrant activation of signaling pathways like the JNK pathway resulting in neuronal cell death by unknown mechanism(s). Using candidate based forward genetic screening, we identified N‐acetyltransferase 9 (NAT9) as one of the genetic modifiers of GMR>Aβ42 reduced eye phenotype. Previously NAT9 has been shown to stabilize microtubules by acetylatio...

genesis

SummaryDuring organogenesis, cell proliferation is followed by the differentiation of specific ce... more SummaryDuring organogenesis, cell proliferation is followed by the differentiation of specific cell types to form an organ. Any aberration in differentiation can result in developmental defects, which can result in a partial to a near‐complete loss of an organ. We employ the Drosophila eye model to understand the genetic and molecular mechanisms involved in the process of differentiation. In a forward genetic screen, we identified, cullin‐4 (cul‐4), which encodes an E3 ubiquitin ligase, to play an important role in retinal differentiation. During development, cul‐4 is known to be involved in protein degradation, regulation of genomic stability, and regulation of cell cycle. Previously, we have reported that cul‐4 regulates cell death during eye development by downregulating Wingless (Wg)/Wnt signaling pathway. We found that loss‐of‐function of cul‐4 results in a reduced eye phenotype, which can be due to onset of cell death. However, we found that loss‐of‐function of cul‐4 also affe...

Neural Regeneration Research

STAR Protocols, 2022

Summary Cell death maintains tissue homeostasis by eliminating dispensable cells. Misregulation o... more Summary Cell death maintains tissue homeostasis by eliminating dispensable cells. Misregulation of cell death is seen in diseases like cancer, neurodegeneration, etc. Therefore, cell death assays like TUNEL have become reliable tools, where fragmented DNA of dying cells gets fluorescently labeled and can be detected under microscope. We used TUNEL assay in Drosophila melanogaster third-instar larval eye-antennal imaginal discs to label and quantify cell death. This assay is sensitive to detect DNA fragmentation, an important event, during apoptosis in retinal neurons. For complete details on the use and execution of this profile, please refer to Wang et al. (1999), Tare et al. (2011), and Mehta et al. (2021).

Alzheimer's & Dementia, 2021

Alzheimer’s disease (AD), an age‐related progressive neurodegenerative disorder, exhibits reduced... more Alzheimer’s disease (AD), an age‐related progressive neurodegenerative disorder, exhibits reduced cognitive functions with no cure to date. One of the reasons for AD is the extracellular accumulation of Amyloid‐beta 42 (Aβ42) plaques. Misexpression of human Aβ42 in the developing retina of Drosophila exhibits AD‐like neuropathology. Accumulation of Aβ42 plaque(s) triggers aberrant signaling resulting in neuronal cell death by unknown mechanism(s).

BioTechniques, 2021

Numerous imaging modules are utilized to study changes that occur during cellular processes. Besi... more Numerous imaging modules are utilized to study changes that occur during cellular processes. Besides qualitative (immunohistochemical) or semiquantitative (Western blot) approaches, direct quantitation method(s) for detecting and analyzing signal intensities for disease(s) biomarkers are lacking. Thus, there is a need to develop method(s) to quantitate specific signals and eliminate noise during live tissue imaging. An increase in reactive oxygen species (ROS) such as superoxide (O2•-) radicals results in oxidative damage of biomolecules, which leads to oxidative stress. This can be detected by dihydroethidium staining in live tissue(s), which does not rely on fixation and helps prevent stress on tissues. However, the signal-to-noise ratio is reduced in live tissue staining. We employ the Drosophila eye model of Alzheimer's disease as a proof of concept to quantitate ROS in live tissue by adapting an unbiased method. The method presented here has a potential application for othe...

Social Science Research Network, 2021

A fundamental process of regeneration, which varies among animals, recruits conserved signaling p... more A fundamental process of regeneration, which varies among animals, recruits conserved signaling pathways to restore missing parts. Only a few animals like newts can repeatedly regenerate lost body parts throughout their lifespan that can be attributed to strategic regulation of conserved signaling pathways by newt’s regeneration tool-kit genes. Lack of genetic tools pose challenges to understand the molecular genetic mechanism of regeneration response of these genes. Here we report use of genetically tractable Drosophila eye model to demonstrate the regeneration potential of a group of unique protein(s) from newt (Notophthalmus viridescens), which when ectopically expressed can significantly rescue missing photoreceptor cells in a Drosophila eye mutant. These newt proteins with signal peptides motifs exhibit non-cell-autonomous rescue properties and their regeneration potential even extends into later stages of fly development. Ectopic expression of these newt genes can rescue eye ...

Annals of Diagnostic Pathology, 2021

BACKGROUND Breast cancer is the most common malignancy in women caused by genetic and epigenetic ... more BACKGROUND Breast cancer is the most common malignancy in women caused by genetic and epigenetic changes. Promoter DNA methylation in tumor suppressor gene plays a major role in breast cancer. The study determined the association of promoter DNA methylation of RASSF1A gene with clinicopathological features in tumor and non-tumor tissue. MATERIALS AND METHODS A cross sectional study was conducted in the Department of Pathology, Government Institute of Medical Sciences, Greater Noida and Molecular Pathology Laboratory, Department of Pathology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Medical Sciences. Two sections, one from tumor and the other from non-tumor tissue, were obtained and processed for DNA extraction and bisulphite conversion. Methylation specific PCR was done and results of RASSF1A promoter methylation were statistically correlated with clinicopathological features. RESULTS Of the 27 breast cancer tissue, 22 showed invasive ductal carcinoma, one showed invasive lobular carcinoma, another showed ductal carcinoma in situ and three cases showed malignant phyllodes tumor of breast. DNA promoter methylation was found in all the cases. 93% of tumor tissue samples and 67% of the non-tumor tissue samples were found to be aberrantly methylated. Tumor size and histological grade were found to be significantly (p-val <0.05) associated with the RASSF1A gene promoter methylation. CONCLUSION A significant association of higher tumor size and tumor histological grade with promoter methylation of RASSF1A gene exists suggestive of its being an important determinant of prognostic staging. This critical event in tumorigenesis may be of clinical utility in assessing breast cancer progression. MICRO ABSTRACT The study focuses on the RASSF1A gene promoter methylation and its impact on the clinicopathological features in Indian breast cancer patients highlighting the differences from other genetically different population. We found that RASFF1A gene methylation has significant impact on tumor size and tumor grade. The work carries high significance because it addresses the DNA methylation of tumor suppressor gene in relevance of breast cancer. It may also be the first such report on Indian patients with breast cancer.

iScience, 2021

Summary Newts utilize their unique genes to restore missing parts by strategic regulation of cons... more Summary Newts utilize their unique genes to restore missing parts by strategic regulation of conserved signaling pathways. Lack of genetic tools poses challenges to determine the function of such genes. Therefore, we used the Drosophila eye model to demonstrate the potential of 5 unique newt (Notophthalmus viridescens) gene(s), viropana1-viropana5 (vna1-vna5), which were ectopically expressed in L2 mutant and GMR-hid, GMR-GAL4 eye. L2 exhibits the loss of ventral half of early eye and head involution defective (hid) triggers cell-death during later eye development. Surprisingly, newt genes significantly restore missing photoreceptor cells both in L2 and GMR>hid background by upregulating cell-proliferation and blocking cell-death, regulating evolutionarily conserved Wingless (Wg)/Wnt signaling pathway and exhibit non-cell-autonomous rescues. Further, Wg/Wnt signaling acts downstream of newt genes. Our data highlights that unique newt proteins can regulate conserved pathways to trigger a robust restoration of missing photoreceptor cells in Drosophila eye model with weak restoration capability.

iScience, 2020

To understand the progression of Alzheimer's disease, studies often rely on ectopic expression of... more To understand the progression of Alzheimer's disease, studies often rely on ectopic expression of amyloid-beta 42 (Ab42) throughout an entire tissue. Uniform ectopic expression of Ab42 may obscure cell-cell interactions that contribute to the progression of the disease. We developed a two-clone system to study the signaling cross talk between GFP-labeled clones of Ab42-expressing neurons and wild-type neurons simultaneously generated from the same progenitor cell by a single recombination event. Surprisingly, wild-type clones are reduced in size as compared with Ab42-producing clones. We found that wildtype cells are eliminated by the induction of cell death. Furthermore, aberrant activation of c-Jun-N-terminal kinase (JNK) signaling in Ab42-expressing neurons sensitizes neighboring wild-type cells to undergo progressive neurodegeneration. Blocking JNK signaling in Ab42-producing clones restores the size of wildtype clones.

Neural Regeneration Research, 2021

During development, regulation of organ size requires a balance between cell proliferation, growt... more During development, regulation of organ size requires a balance between cell proliferation, growth and cell death. Dysregulation of these fundamental processes can cause a variety of diseases. Excessive cell proliferation results in cancer whereas excessive cell death results in neurodegenerative disorders. Many signaling pathways known-to-date have a role in growth regulation. Among them, evolutionarily conserved Hippo signaling pathway is unique as it controls both cell proliferation and cell death by a variety of mechanisms during organ sculpture and development. Neurodegeneration, a complex process of progressive death of neuronal population, results in fatal disorders with no available cure to date. During normal development, cell death is required for sculpting of an organ. However, aberrant cell death in neuronal cell population can result in neurodegenerative disorders. Hippo pathway has gathered major attention for its role in growth regulation and cancer, however, other functions like its role in neurodegeneration are also emerging rapidly. This review highlights the role of Hippo signaling in cell death and neurodegenerative diseases and provide the information on the chemical inhibitors employed to block Hippo pathway. Understanding Hippo mediated cell death mechanisms will aid in development of reliable and effective therapeutic strategies in future.

Neurobiology of Disease, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Datta Meghe Institute of Medical Sciences University, 2018

Transposable elements (TEs) comprise almost 45% of the human genome. There are DNA transposons an... more Transposable elements (TEs) comprise almost 45% of the human genome. There are DNA transposons and RNA transposons. Retrotransposons like long interspersed nuclear element 1 (LINE 1) is abundant among all the TEs and present in 17% of the genome. These elements have repetitive sequences. Retrotransposons are regulated by epigenetic modification like methylation alteration of which leads to aberrant expression of LINE1. The literature says that loss of methylation of global DNA is associated with the imitation and progression of cancer. LINE 1 methylation status can be considered as a biomarker for cancer. The hypomethylation of LINE 1 causes transcriptional deregulation, genomic instability, chromosomal recombination, activation of oncogenes, and repression of tumor suppressor genes. There is less evidence on genomic instability and the mechanism underlying the cancer progression due to hypomethylation of LINE 1 elements. Hence, the methylation of LINE1 could be the possible marker for the prognosis of cancer.

Frontiers in Cell and Developmental Biology, 2020

Alzheimer's disease (AD, OMIM: 104300) is an age-related disorder that affects millions of people... more Alzheimer's disease (AD, OMIM: 104300) is an age-related disorder that affects millions of people. One of the underlying causes of AD is generation of hydrophobic amyloid-beta 42 (Aβ42) peptides that accumulate to form amyloid plaques. These plaques induce oxidative stress and aberrant signaling, which result in the death of neurons and other pathologies linked to neurodegeneration. We have developed a Drosophila eye model of AD by targeted misexpression of human Aβ42 in the differentiating retinal neurons, where an accumulation of Aβ42 triggers a characteristic neurodegenerative phenotype. In a forward deficiency screen to look for genetic modifiers, we identified a molecularly defined deficiency, which suppresses Aβ42-mediated neurodegeneration. This deficiency uncovers hippo (hpo) gene, a member of evolutionarily conserved Hippo signaling pathway that regulates growth. Activation of Hippo signaling causes cell death, whereas downregulation of Hippo signaling triggers cell proliferation. We found that Hippo signaling is activated in Aβ42-mediated neurodegeneration. Downregulation of Hippo signaling rescues the Aβ42-mediated neurodegeneration, whereas upregulation of Hippo signaling enhances the Aβ42-mediated neurodegeneration phenotypes. It is known that c-Jun-amino-terminal kinase (JNK) signaling pathway is upregulated in AD. We found that activation of JNK signaling enhances the Aβ42-mediated neurodegeneration, whereas downregulation of JNK signaling rescues the Aβ42-mediated neurodegeneration. We tested the nature of interactions between Hippo signaling and JNK signaling in Aβ42-mediated neurodegeneration using genetic epistasis approach. Our data suggest that Hippo signaling and JNK signaling, two independent signaling pathways, act synergistically upon accumulation of Aβ42 plaques to trigger cell death. Our studies demonstrate a novel role of Hippo signaling pathway in Aβ42-mediated neurodegeneration.

Neural Regeneration Research, 2019

Alzheimer's disease (hereafter AD) is a progressive neurodegenerative disorder that affects the c... more Alzheimer's disease (hereafter AD) is a progressive neurodegenerative disorder that affects the central nervous system. There are multiple factors that cause AD, viz., accumulation of extracellular Amyloid-beta 42 plaques, intracellular hyper-phosphorylated Tau tangles, generation of reactive oxygen species due to mitochondrial dysfunction and genetic mutations. The plaques and tau tangles trigger aberrant signaling, which eventually cause cell death of the neurons. As a result, there is shrinkage of brain, cognitive defects, behavioral and psychological problems. To date, there is no direct cure for AD. Thus, scientists have been testing various strategies like screening for the small inhibitor molecule library or natural products that may block or prevent onset of AD. Historically, natural products have been used in many cultures for the treatment of various diseases. The research on natural products have gained importance as the active compounds extracted from them have medicinal values with reduced side effects, and they are bioavailable. The natural products may target the proteins or members of signaling pathways that get altered in specific diseases. Many natural products are being tested in various animal model systems for their role as a potential therapeutic target for AD, and to address questions about how these natural products can rescue AD or other neurodegenerative disorders. Some of these products are in clinical trials and results are promising because of their neuroprotective, anti-inflammatory, antioxidant, anti-amyloidogenic, anticholinesterase activities and easy availability. This review summarizes the use of animal model systems to identify natural products, which may serve as potential therapeutic targets for AD.