scispace - formally typeset
Search or ask a question
Author

Gaurav Datta

Bio: Gaurav Datta is an academic researcher from University of North Dakota. The author has contributed to research in topics: Plasmodium falciparum & Hemozoin. The author has an hindex of 8, co-authored 18 publications receiving 159 citations. Previous affiliations of Gaurav Datta include International Centre for Genetic Engineering and Biotechnology.

Papers
More filters
Journal ArticleDOI
TL;DR: It is shown that persistent cellular stress and organelle dysfunction because of disruption of cellular homeostasis in human malaria parasite Plasmodium falciparum, leads to apoptosis-like cell death, establishing one of the possible mechanisms of instigation of cell death by organelle stress in PlasModium.
Abstract: A regulated protein turnover machinery in the cell is essential for effective cellular homeostasis; any interference with this system induces cellular stress and alters the normal functioning of proteins important for cell survival. In this study, we show that persistent cellular stress and organelle dysfunction because of disruption of cellular homeostasis in human malaria parasite Plasmodium falciparum, leads to apoptosis-like cell death. Quantitative global proteomic analysis of the stressed parasites before onset of cell death, showed upregulation of a number of proteins involved in cellular homeostasis; protein network analyses identified upregulated metabolic pathways that may be associated with stress tolerance and pro-survival mechanism. However, persistent stress on parasites cause structural abnormalities in endoplasmic reticulum and mitochondria, subsequently a cascade of reactions are initiated in parasites including rise in cytosolic calcium levels, loss of mitochondrial membrane potential and activation of VAD-FMK-binding proteases. We further show that activation of VAD-FMK-binding proteases in the parasites leads to degradation of phylogenetically conserved protein, TSN (Tudor staphylococcal nuclease), a known target of metacaspases, as well as degradation of other components of spliceosomal complex. Loss of spliceosomal machinery impairs the mRNA splicing, leading to accumulation of unprocessed RNAs in the parasite and thus dysregulate vital cellular functions, which in turn leads to execution of apoptosis-like cell death. Our results establish one of the possible mechanisms of instigation of cell death by organelle stress in Plasmodium.

51 citations

Journal ArticleDOI
TL;DR: It is shown that the dominant negative effect of PfClpQ(mut) disrupted transcription of mitochondrial genome encoded genes, which in turn blocked normal development and functioning of the mitochondria in the parasite.
Abstract: Summary The ATP-dependent ClpQY system is a prokaryotic proteasome-like multi-subunit machinery localized in the mitochondrion of malaria parasite. The ClpQY machinery consists of ClpQ threonine pro- tease and ClpY ATPase. In the present study, we have assessed cellular effects of transient interference of PfClpQ protease activity in Plas- modium falciparum using a trans-dominant nega- tive approach combined with FKBP degradation domain system. A proteolytically inactive mutant PfClpQ protein (PfClpQ(mut)) fused with FKBP degradation domain was expressed in parasites, which gets stabilized by Shield1 drug treatment. We show that the inactive PfClpQ(mut) interacts with wild-type PfClpQ and associates within multi- subunit complex in the parasite. Stabilization of the PfClpQ(mut) and its association in the protease machinery caused dominant negative effect in the transgenic parasites, which disrupted the growth cycle of asexual blood stage parasites. The mito- chondria in these parasites showed abnormal mor- phology, these mitochondria were not able to grow and divide in the parasite. We further show that the dominant negative effect of PfClpQ(mut) disrupted transcription of mitochondrial genome encoded genes, which in turn blocked normal development and functioning of the mitochondria.

24 citations

Journal ArticleDOI
TL;DR: A role for the AP-1 complex in rhoptry protein trafficking in P. falciparum is suggested by treatment with AlF4, which resulted in a shift to a predominantly ER-associated compartment and consequent decrease in co-localization with the Golgi marker GRASP.

24 citations

Journal ArticleDOI
TL;DR: The results suggest that gp120-induced lysosome exocytosis and release of ATP from Schwann cells and DRG neurons contribute to the pathogenesis of HIV-1 associated neuropathy.
Abstract: Human immunodeficiency virus type 1 (HIV-1) associated neuropathy is the most common neurological complication of HIV-1, with debilitating pain affecting the quality of life. HIV-1 gp120 plays an important role in the pathogenesis of HIV neuropathy via direct neurotoxic effects or indirect pro-inflammatory responses. Studies have shown that gp120-induced release of mediators from Schwann cells induce CCR5-dependent DRG neurotoxicity, however, CCR5 antagonists failed to improve pain in HIV- infected individuals. Thus, there is an urgent need for a better understanding of neuropathic pain pathogenesis and developing effective therapeutic strategies. Because lysosomal exocytosis in Schwann cells is an indispensable process for regulating myelination and demyelination, we determined the extent to which gp120 affected lysosomal exocytosis in human Schwann cells. We demonstrated that gp120 promoted the movement of lysosomes toward plasma membranes, induced lysosomal exocytosis, and increased the release of ATP into the extracellular media. Mechanistically, we demonstrated lysosome de-acidification, and activation of P2X4 and VNUT to underlie gp120-induced lysosome exocytosis. Functionally, we demonstrated that gp120-induced lysosome exocytosis and release of ATP from Schwann cells leads to increases in intracellular calcium and generation of cytosolic reactive oxygen species in DRG neurons. Our results suggest that gp120-induced lysosome exocytosis and release of ATP from Schwann cells and DRG neurons contribute to the pathogenesis of HIV-1 associated neuropathy.

20 citations

Journal ArticleDOI
01 Jul 2019
TL;DR: It is demonstrated that iron mediates morphine-induced FHC upregulation and consequent dendritic spine deficits and implicate endolysosomal iron efflux to the cytoplasm in these effects.
Abstract: HIV-associated neurocognitive disorders (HAND) remain prevalent and are aggravated by µ-opioid use. We have previously shown that morphine and other µ-opioids may contribute to HAND by inhibiting the homeostatic and neuroprotective chemokine receptor CXCR4 in cortical neurons, and this novel mechanism depends on upregulation of the protein ferritin heavy chain (FHC). Here, we examined the cellular events and potential mechanisms involved in morphine-mediated FHC upregulation using rat cortical neurons of either sex in vitro and in vivo. Morphine dose dependently increased FHC protein levels in primary neurons through µ-opioid receptor (µOR) and Gαi-protein signaling. Cytoplasmic FHC levels were significantly elevated, but nuclear FHC levels and FHC gene expression were unchanged. Morphine-treated rats also displayed increased FHC levels in layer 2/3 neurons of the prefrontal cortex. Importantly, both in vitro and in vivo FHC upregulation was accompanied by loss of mature dendritic spines, which was also dependent on µOR and Gαi-protein signaling. Moreover, morphine upregulated ferritin light chain (FLC), a component of the ferritin iron storage complex, suggesting that morphine altered neuronal iron metabolism. Indeed, prior to FHC upregulation, morphine increased cytoplasmic labile iron levels as a function of decreased endolysosomal iron. In line with this, chelation of endolysosomal iron (but not extracellular iron) blocked morphine-induced FHC upregulation and dendritic spine reduction, whereas iron overloading mimicked the effect of morphine on FHC and dendritic spines. Overall, these data demonstrate that iron mediates morphine-induced FHC upregulation and consequent dendritic spine deficits and implicate endolysosomal iron efflux to the cytoplasm in these effects.

19 citations


Cited by
More filters
Journal Article
TL;DR: In this paper, a single-blind study was conducted to investigate whether the progression of dementia could be slowed by the trivalent ion chelator, desferrioxamine.
Abstract: Although epidemiological and biochemical evidence suggests that aluminium may be associated with Alzheimer's disease (AD), there is no convincing proof of a causal link for aluminium in disease progression. We have completed a two year, single-blind study to investigate whether the progression of dementia could be slowed by the trivalent ion chelator, desferrioxamine. 48 patients with probable AD were randomly assigned to receive desferrioxamine (125 mg intramuscularly twice daily, 5 days per week, for 24 months), oral placebo (lecithin), or no treatment. No significant differences in baseline measures of intelligence, memory, or speech ability existed between groups. Activities of daily living were assessed and videorecorded at 6, 12, 18, and 24 month intervals. There were no differences in the rate of deterioration of patients receiving either placebo or no treatment. Desferrioxamine treatment led to significant reduction in the rate of decline of daily living skills as assessed by both group means (p = 0.03) and variances (p less than 0.04). The mean rate of decline was twice as rapid for the no-treatment group. Appetite (n = 4) and weight (n = 1) loss were the only reported side-effects. We conclude that sustained administration of desferrioxamine may slow the clinical progression of the dementia associated with AD.

580 citations

01 Jan 2016
TL;DR: It is proposed that intracellular iron levels regulate ferritin synthesis by causing changes in specific protein binding to the conserved sequence in the ferritIn heavy- and light-subunit mRNAs.
Abstract: The mRNAs for the heavy and light subunits of the iron-storage protein ferritin occur in cells largely as inactive ribonucleoprotein particles, which are recruited for translation when iron enters the cell. Cytoplasmic extracts from rat tissues and hepatoma cells were shown by an electro- phoretic separation procedure to form RNA-protein com- plexes involving a highly conserved sequence in the 5' untrans- lated region of both ferritin heavy- and light-subunit mRNAs. The pattern of complex formation was affected by pretreat- ment of rats or cells with iron. Crosslinking by UV irradiation showed that the complexes contained an 87-kDa protein inter- acting with the conserved sequence of the ferritin mRNA. We propose that intracellular iron levels regulate ferritin synthesis by causing changes in specific protein binding to the conserved sequence in the ferritin heavy- and light-subunit mRNAs. Femtin, an iron-storage protein found in animal, plant, fungal, and bacterial cells (1), has a protein shell (Mr = 500,000) consisting in vertebrates of 24 subunits of two kinds, heavy (H; Mr 20,000) and light (L; Mr 19,000).

509 citations

01 Jan 1990
TL;DR: Low density lipoprotein receptor-related protein (LRP) is a cell surface glycoprotein that binds and transports plasma lipoproteins enriched in apolipoprotein E as discussed by the authors.
Abstract: The low density lipoprotein receptor‐related protein (LRP) is a cell surface glycoprotein that binds and transports plasma lipoproteins enriched in apolipoprotein E. It is synthesized in the endoplasmic reticulum as a transmembrane glycosylated precursor that migrates with an apparent molecular mass of about 600 kd on SDS‐polyacrylamide gels. After it reaches the Golgi complex, the protein is cleaved to generate two subunits with apparent molecular masses of approximately 515 and 85 kd respectively. The larger NH2‐terminal alpha‐subunit lacks a membrane‐spanning region. It remains attached to the membrane through noncovalent association with the smaller COOH‐terminal beta‐subunit. Proteolysis occurs at the sequence RHRR, which resembles the sequence RKRR at the proteolytic site in the receptors for insulin and insulin‐like growth factor‐1 (IGF‐1), the only other cell surface receptors known to undergo proteolytic processing. Proteolysis of LRP occurs coincident with the conversion of the N‐linked carbohydrates to the mature endoglycosidase H‐resistant, neuraminidase‐sensitive form. Proteolysis is prevented by brefeldin A, which blocks transport to the Golgi complex. These data raise the possibility that LRP and the receptors for insulin and IGF‐1 are processed by a specific endoprotease that recognizes protein with extended basic sequences and resides in the trans‐Golgi complex or in post‐Golgi vesicles of the constitutive secretory pathway.

229 citations

Journal ArticleDOI
TL;DR: The insights that have been gained into the function of genes that are important during the blood stages of the parasites may help to guide the development and improvement of drug therapies and vaccines.
Abstract: Robust tools for analysing gene function in Plasmodium parasites, which are the causative agents of malaria, are being developed at an accelerating rate Two decades after genetic technologies for use in Plasmodium spp were first described, a range of genetic tools are now available These include conditional systems that can regulate gene expression at the genome, transcriptional or protein level, as well as more sophisticated tools for gene editing that use piggyBac transposases, integrases, zinc-finger nucleases or the CRISPR-Cas9 system In this Review, we discuss the molecular genetic systems that are currently available for use in Plasmodium falciparum and Plasmodium berghei, and evaluate the advantages and limitations of these tools We examine the insights that have been gained into the function of genes that are important during the blood stages of the parasites, which may help to guide the development and improvement of drug therapies and vaccines

108 citations