Publications by authors named "Sayan Ghosh"

27 Publications

  • Page 1 of 1

βA3/A1-crystallin regulates apical polarity and EGFR endocytosis in retinal pigmented epithelial cells.

Commun Biol 2021 07 8;4(1):850. Epub 2021 Jul 8.

Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

The retinal pigmented epithelium (RPE) is a monolayer of multifunctional cells located at the back of the eye. High membrane turnover and polarization, including formation of actin-based apical microvilli, are essential for RPE function and retinal health. Herein, we demonstrate an important role for βA3/A1-crystallin in RPE. βA3/A1-crystallin deficiency leads to clathrin-mediated epidermal growth factor receptor (EGFR) endocytosis abnormalities and actin network disruption at the apical side that result in RPE polarity disruption and degeneration. We found that βA3/A1-crystallin binds to phosphatidylinositol transfer protein (PITPβ) and that βA3/A1-crystallin deficiency diminishes phosphatidylinositol 4,5-biphosphate (PI(4,5)P), thus probably decreasing ezrin phosphorylation, EGFR activation, internalization, and degradation. We propose that βA3/A1-crystallin acquired its RPE function before evolving as a structural element in the lens, and that in the RPE, it modulates the PI(4,5)P pool through PITPβ/PLC signaling axis, coordinates EGFR activation, regulates ezrin phosphorylation and ultimately the cell polarity.
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http://dx.doi.org/10.1038/s42003-021-02386-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8266859PMC
July 2021

Pomegranate Polyphenols Attenuate Inflammation and Hepatic Damage in Tumor-Bearing Mice: Crucial Role of NF-κB and the Nrf2/GSH Axis.

J Nutr Biochem 2021 Jul 2;97:108812. Epub 2021 Jul 2.

Department of Physiology, University of Calcutta; Kolkata, India; Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, Kolkata, India. Electronic address:

It has been widely reported that cancer, along with its treatment regimens, cause severe toxicity in the host. A suitable agent having chemopreventive properties as well as capabilities of ameliorating tumor- and drug-induced toxicities is of imminent need. Pomegranate has been projected as an excellent anti-tumor, anti-inflammatory and anti-oxidant agent. In this study, for the first time, we delineated the exact signaling cascade by which dietary supplementation of pomegranate fruit extract (PFE) protects tumor-bearing mice from tumor-induced hepatotoxicity. Increased activities of serum Alanine transaminase, Aspartate transaminase, Lactate dehydrogenase and Alkaline phosphatase, as well as histological studies confirmed the establishment of a state of hepatic dysfunction in tumor-bearers. Further investigations revealed that increased hepatic reactive oxygen species content and glutathione depletion-initiated apoptosis in these hepatocytes as we observed an alteration in the apoptotic proteins. PFE supplementation in tumor-bearing mice, on the other hand, differentially modulated redox-sensitive transcription factors Nrf2 and NF-κB, ultimately decreasing tumor-induced hepatic oxidative damage and cell death. siRNA-mediated inhibition of Nrf2 and NF-κB completely abolished the hepato-protective activities of PFE while pre-treatment of tumor-conditioned hepatocytes with N-acetyl cysteine augmented the cyto-protective properties of PFE. The present study clearly identified Nrf2/NF-κB/glutathione axis as the key factor behind the hepatoprotective potential of PFE. These findings would add to the existing knowledge about cancer chemoprevention by dietary polyphenols and might lead to the application of pomegranate polyphenols as supplement to escalate the effectiveness of cancer therapy by protecting normal cells from cancer related toxicities.
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http://dx.doi.org/10.1016/j.jnutbio.2021.108812DOI Listing
July 2021

βA1-crystallin regulates glucose metabolism and mitochondrial function in mouse retinal astrocytes by modulating PTP1B activity.

Commun Biol 2021 02 24;4(1):248. Epub 2021 Feb 24.

Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

βA3/A1-crystallin, a lens protein that is also expressed in astrocytes, is produced as βA3 and βA1-crystallin isoforms by leaky ribosomal scanning. In a previous human proteome high-throughput array, we found that βA3/A1-crystallin interacts with protein tyrosine phosphatase 1B (PTP1B), a key regulator of glucose metabolism. This prompted us to explore possible roles of βA3/A1-crystallin in metabolism of retinal astrocytes. We found that βA1-crystallin acts as an uncompetitive inhibitor of PTP1B, but βA3-crystallin does not. Loss of βA1-crystallin in astrocytes triggers metabolic abnormalities and inflammation. In CRISPR/cas9 gene-edited βA1-knockdown (KD) mice, but not in βA3-knockout (KO) mice, the streptozotocin (STZ)-induced diabetic retinopathy (DR)-like phenotype is exacerbated. Here, we have identified βA1-crystallin as a regulator of PTP1B; loss of this regulation may be a new mechanism by which astrocytes contribute to DR. Interestingly, proliferative diabetic retinopathy (PDR) patients showed reduced βA1-crystallin and higher levels of PTP1B in the vitreous humor.
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http://dx.doi.org/10.1038/s42003-021-01763-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904954PMC
February 2021

BNIP3L-mediated mitophagy is required for mitochondrial remodeling during the differentiation of optic nerve oligodendrocytes.

Autophagy 2021 Jan 19:1-20. Epub 2021 Jan 19.

Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

Retinal ganglion cell axons are heavily myelinated (98%) and myelin damage in the optic nerve (ON) severely affects vision. Understanding the molecular mechanism of oligodendrocyte progenitor cell (OPC) differentiation into mature oligodendrocytes will be essential for developing new therapeutic approaches for ON demyelinating diseases. To this end, we developed a new method for isolation and culture of ON-derived oligodendrocyte lineage cells and used it to study OPC differentiation. A critical aspect of cellular differentiation is macroautophagy/autophagy, a catabolic process that allows for cell remodeling by degradation of excess or damaged cellular molecules and organelles. Knockdown of ATG9A and BECN1 (pro-autophagic proteins involved in the early stages of autophagosome formation) led to a significant reduction in proliferation and survival of OPCs. We also found that autophagy flux (a measure of autophagic degradation activity) is significantly increased during progression of oligodendrocyte differentiation. Additionally, we demonstrate a significant change in mitochondrial dynamics during oligodendrocyte differentiation, which is associated with a significant increase in programmed mitophagy (selective autophagic clearance of mitochondria). This process is mediated by the mitophagy receptor BNIP3L (BCL2/adenovirus E1B interacting protein 3-like). BNIP3L-mediated mitophagy plays a crucial role in the regulation of mitochondrial network formation, mitochondrial function and the viability of newly differentiated oligodendrocytes. Our studies provide novel evidence that proper mitochondrial dynamics is required for establishment of functional mitochondria in mature oligodendrocytes. These findings are significant because targeting BNIP3L-mediated programmed mitophagy may provide a novel therapeutic approach for stimulating myelin repair in ON demyelinating diseases. A2B5: a surface antigen of oligodendrocytes precursor cells, A2B5 clone 105; ACTB: actin, beta; APC: an antibody to label mature oligodendrocytes, anti-adenomatous polyposis coli clone CC1; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG9A: autophagy related 9A; AU: arbitrary units; BafA1: bafilomycin A1; BCL2: B cell leukemia/lymphoma 2; BECN1: beclin 1, autophagy related; BNIP3: BCL2/adenovirus E1B interacting protein 3; BNIP3L/NIX: BCL2/adenovirus E1B interacting protein 3-like; CASP3: caspase 3; CNP: 2',3'-cyclic nucleotide 3'-phosphodiesterase; Ctl: control; COX8: cytochrome c oxidase subunit; CSPG4/NG2: chondroitin sulfate proteoglycan 4; DAPI: 4'6-diamino-2-phenylindole; DNM1L: dynamin 1-like; EGFP: enhanced green fluorescent protein; FACS: fluorescence-activated cell sorting; FIS1: fission, mitochondrial 1; FUNDC1: FUN14 domain containing 1; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFAP: glial fibrillary growth factor; GFP: green fluorescent protein; HsESC: human embryonic stem cell; IEM: immunoelectron microscopy; LAMP1: lysosomal-associated membrane protein 1; LC3B: microtubule-associated protein 1 light chain 3; MBP: myelin basic protein; MFN2: mitofusin 2; Mito-Keima: mitochondria-targeted monomeric keima-red; Mito-GFP: mitochondria-green fluorescent protein; Mito-RFP: mitochondria-red fluorescent protein; MitoSOX: red mitochondrial superoxide probe; MKI67: antigen identified by monoclonal antibody Ki 67; MMP: mitochondrial membrane potential; O4: oligodendrocyte marker O4; OLIG2: oligodendrocyte transcription factor 2; ON: optic nerve; OPA1: OPA1, mitochondrial dynamin like GTPase; OPC: oligodendrocyte progenitor cell; PDL: poly-D-lysine; PINK1: PTEN induced putative kinase 1; PRKN/Parkin: parkin RBR E3 ubiquitin protein ligase; RFP: red fluorescent protein; RGC: retinal ganglion cell; ROS: reactive oxygen species; RT-PCR: real time polymerase chain reaction; SEM: standard error of the mean; SOD2: superoxide dismutase 2, mitochondrial; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy; TMRM: tetramethylrhodamine methyl ester; TOMM20: translocase of outer mitochondrial membrane 20; TUBB: tubulin, beta; TUBB3: tubulin, beta 3 class III.
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http://dx.doi.org/10.1080/15548627.2020.1871204DOI Listing
January 2021

Different Growth Responses to Recombinant Human Growth Hormone in Three Siblings with Isolated Growth Hormone Deficiency Type IA due to 6.7Kb Deletion of GH1 Gene.

J Clin Res Pediatr Endocrinol 2020 Sep 17. Epub 2020 Sep 17.

Department of Zoology, University of Calcutta 35 B.C. Road, Kolkata.

Isolated growth hormone (GH) deficiency type I A is a rare autosomal recessive disorder caused by deletion of the GH1 gene and characterized by early onset severe short stature and typical phenotype. Lack of exposure to GH during fetal life often leads to formation of anti-GH antibody following exposure to the least immunogenic recombinant human GH (rhGH). Some patients with circulating ant-GH antibodies demonstrate lack of growth response to GH while others do not. However, the clinical significance of this antibody is unclear hence not routinely recommended. Three siblings born of a consanguineous union were referred to us with severe short stature. They were evaluated and IGHD was diagnosed in all of them. Genetic analysis revealed homozygous 6.7 Kb deletions of GH1 gene in all of them while their parents displayed a pattern of heterozygous 6.7 Kb deletions. rhGH was started at 10, 6 and 17/12 years of age. Their growth and hormonal parameters were monitored throughout the course of treatment. The eldest sibling demonstrated usual growth velocity (9.5 cm/year) after start of therapy that rapidly waned after 1st year (2.5 cm/year). The youngest sibling experienced excellent growth response even after 3rd year (10.3 cm/year) while the middle one displayed sub-optimal response from beginning (6.3cm/year). Change of rhGH brand did not work in the two elder sisters. Such a different growth response with rhGH in three siblings harbouring similar genetic abnormality has not been described earlier. Keywords: Isolated growth hormone deficiency type IA, GH1 gene, Anti-GH antibody.
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http://dx.doi.org/10.4274/jcrpe.galenos.2020.2020.0005DOI Listing
September 2020

Role of glia in optic nerve.

Prog Retin Eye Res 2021 03 6;81:100886. Epub 2020 Aug 6.

Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. Electronic address:

Glial cells are critically important for maintenance of neuronal activity in the central nervous system (CNS), including the optic nerve (ON). However, the ON has several unique characteristics, such as an extremely high myelination level of retinal ganglion cell (RGC) axons throughout the length of the nerve (with virtually all fibers myelinated by 7 months of age in humans), lack of synapses and very narrow geometry. Moreover, the optic nerve head (ONH) - a region where the RGC axons exit the eye - represents an interesting area that is morphologically distinct in different species. In many cases of multiple sclerosis (demyelinating disease of the CNS) vision problems are the first manifestation of the disease, suggesting that RGCs and/or glia in the ON are more sensitive to pathological conditions than cells in other parts of the CNS. Here, we summarize current knowledge on glial organization and function in the ON, focusing on glial support of RGCs. We cover both well-established concepts on the important role of glial cells in ON health and new findings, including novel insights into mechanisms of remyelination, microglia/NG2 cell-cell interaction, astrocyte reactivity and the regulation of reactive astrogliosis by mitochondrial fragmentation in microglia.
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http://dx.doi.org/10.1016/j.preteyeres.2020.100886DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865017PMC
March 2021

The role of lipocalin-2 in age-related macular degeneration (AMD).

Cell Mol Life Sci 2020 Mar 4;77(5):835-851. Epub 2020 Jan 4.

Department of Ophthalmology, Children's Hospital of University of Pittsburgh School of Medicine, One Children's Hospital Drive, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.

Lipocalins are a family of secreted adipokines which play important roles in various biological processes. Lipocalin-2 (LCN-2) has been shown to be involved in acute and chronic inflammation. This particular protein is critical in the pathogenesis of several diseases including cancer, diabetes, obesity, and multiple sclerosis. Herein, we discuss the general molecular basis for the involvement of LCN-2 in acute infections and chronic disease progression and also ascertain the probable role of LCN-2 in ocular diseases, particularly in age-related macular degeneration (AMD). We elaborate on the signaling cascades which trigger LCN-2 upregulation in AMD and suggest therapeutic strategies for targeting such pathways.
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http://dx.doi.org/10.1007/s00018-019-03423-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079812PMC
March 2020

Melatonin as the Possible Link Between Age-Related Retinal Regeneration and the Disrupted Circadian Rhythm in Elderly.

Adv Exp Med Biol 2019 ;1185:45-49

Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

The association between age-related macular degeneration (AMD) and biological rhythms has been insufficiently studied; however there are several reasons to believe that impairment in circadian rhythm may affect incidence and pathogenesis of AMD. The current understanding of AMD pathology is based on age-related, cumulative oxidative damage to the retinal pigmented epithelium (RPE) partially due to impaired clearance of phagocytosed photoreceptor outer segments. In higher vertebrates, phagocytosis of the outer segments is synchronized by circadian rhythms and occurs shortly after dawn, followed by lysosomal-mediated clearance. Aging has been shown to be associated with the changes in circadian rhythmicity of melatonin production, which can be a major factor contributing to the impaired balance between phagocytosis and clearance and increased levels of reactive oxygen species resulting in degenerative changes in the retina. This minireview summarizes studies linking AMD with melatonin production and discusses challenges and perspectives of this area of research.
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http://dx.doi.org/10.1007/978-3-030-27378-1_8DOI Listing
February 2020

Inflammation-induced behavioral changes is driven by alterations in Nrf2-dependent apoptosis and autophagy in mouse hippocampus: Role of fluoxetine.

Cell Signal 2020 04 24;68:109521. Epub 2019 Dec 24.

Department of Physiology, University of Calcutta; UCSTA, 92, Acharya Prafulla Chandra Road, Kolkata 700009, India; Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Salt Lake, Sector III, Kolkata 700098, India. Electronic address:

Inflammation has been associated with the progression of many neurological diseases. Peripheral inflammation has also been vaguely linked to depression-like symptoms in animal models, but the underlying pathways that orchestrate inflammation-induced behavioral or molecular changes in the brain are still elusive. We have recently shown that intraperitoneal injections of lipopolysaccharide (LPS) to Swiss albino mice triggers systemic inflammation, leading to an activated immune response along with changes in monoamine levels in the brain. Herein we pinpoint the fundamental pathways linking peripheral inflammation and depression-like behavior in a mouse model, thereby identifying suitable targets of intervention to combat the situation. We show that LPS-induced peripheral inflammation provoked a depression-like behavior in mice and a distinct pro-inflammatory bias in the hippocampus, as evident from increased microglial activation and elevated levels of pro-inflammatory cytokines IL-6 and TNF-α, and activation of NFκB-p65 pathway. Significant alterations in Nrf2-dependent cellular redox status, coupled with altered autophagy and increased apoptosis were noticed in the hippocampus of LPS-exposed mice. We and others have previously shown that, fluoxetine (an anti-depressant) has effective anti-inflammatory and antioxidant properties by virtue of its abilities to regulate NFκB and Nrf2 signaling. We observed that treatment with fluoxetine or the Nrf2 activator tBHQ (tert-butyl hydroquinone), could reverse depression-like-symptoms and mitigate alterations in autophagy and cell death pathways in the hippocampus by activating Nrf2-dependent gene expressions. Taken together, the data suggests that systemic inflammation potentiates Nrf2-dependent changes in cell death and autophagy pathway in the hippocampus, eventually leading to major pathologic sequelae associated with depression. Therefore, targeting Nrf2 could be a novel approach in combatting depression and ameliorating its associated pathogenesis.
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http://dx.doi.org/10.1016/j.cellsig.2019.109521DOI Listing
April 2020

Effects of bamboo shoots (Bambusa balcooa) on thyroid hormone synthesizing regulatory elements at cellular and molecular levels in thyrocytes.

J Ethnopharmacol 2020 Mar 12;250:112463. Epub 2019 Dec 12.

Department of Human Physiology, Ramkrishna Mahavidyalaya (Govt. of Tripura), Kailashahar, Unakoti District, Tripura, 799 277, India.

Ethnopharmacological Relevance: Bamboo shoots (BS) are consumed in various forms and used largely in naturopathy for curing ailments since ancient times to present days. It is eaten in South East Asian countries in several indigenous preparations. In north east India, it is consumed predominantly and used as natural cure to treat various diseases. Although known for its beneficial effects, adverse effects including goitrogenic/antithyroidal potential are emerging.

Aim Of The Study: Endemic goiter exists in Manipur, India even after adequate iodine intake for consumption of BS. It is thus important to study the impact of this goitrogenic food on certain thyroid hormone synthesizing regulatory factors at cellular and molecular level in thyrocytes.

Materials And Methods: Phytochemical analysis of BS - Bambusa balcooa Roxb (BSBR) extract conducted. IC of the extract on thyrocytes in culture was determined. To study the antithyroid effects of this goitrogenic food, activity status of Na-K-ATPase, TPO and Deiodinase, mRNA and protein expressions of NIS, TPO and PAX8 were investigated with and without extra iodine in culture media. Simultaneously ROS generation in terms of HO and antioxidant status, NO, LPO were assayed.

Results: Activities of the studied enzymes decreased depending on dose and time with increased HO, decreased antioxidants followed by increased NO with LPO. DNA damage and LDH also increased while mRNA and protein expression of NIS, TPO and PAX8 were downregulated. Extra iodine ameliorated all such effects partially.

Conclusions: Bioactive constituents of the extract imbalances oxidative status of thyrocytes impairing action of hormone synthesizing elements at cellular and molecular level.
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http://dx.doi.org/10.1016/j.jep.2019.112463DOI Listing
March 2020

Neutrophils homing into the retina trigger pathology in early age-related macular degeneration.

Commun Biol 2019 20;2:348. Epub 2019 Sep 20.

1Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA.

Age-related macular degeneration (AMD) is an expanding problem as longevity increases worldwide. While inflammation clearly contributes to vision loss in AMD, the mechanism remains controversial. Here we show that neutrophils are important in this inflammatory process. In the retinas of both early AMD patients and in a mouse model with an early AMD-like phenotype, we show neutrophil infiltration. Such infiltration was confirmed experimentally using ribbon-scanning confocal microscopy (RSCM) and IFNλ- activated dye labeled normal neutrophils. With neutrophils lacking lipocalin-2 (LCN-2), infiltration was greatly reduced. Further, increased levels of IFNλ in early AMD trigger neutrophil activation and LCN-2 upregulation. LCN-2 promotes inflammation by modulating integrin β1 levels to stimulate adhesion and transmigration of activated neutrophils into the retina. We show that in the mouse model, inhibiting AKT2 neutralizes IFNλ inflammatory signals, reduces LCN-2-mediated neutrophil infiltration, and reverses early AMD-like phenotype changes. Thus, AKT2 inhibitors may have therapeutic potential in early, dry AMD.
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http://dx.doi.org/10.1038/s42003-019-0588-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6754381PMC
April 2020

Arsenic-induced immunomodulatory effects disorient the survival-death interface by stabilizing the Hsp90/Beclin1 interaction.

Chemosphere 2020 Jan 22;238:124647. Epub 2019 Aug 22.

Cancer Research Laboratory, Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700 019, India. Electronic address:

Ground water arsenic contamination is a global menace. Since arsenic may affect the immune system, leading to immunesuppression, we investigated the effects of acute arsenic exposure on the thymus and spleen using Swiss albino mice, exposed to 5 ppm, 15 ppm and 300 ppm of sodium arsenite for 7 d. Effects on cytokine balance and cell survivability were subsequently analyzed. Our data showed that arsenic treatment induced debilitating alterations in the tissue architecture of thymus and spleen. A dose-dependent decrease in the ratio of CD4-CD8 T-cells was observed along with a pro-inflammatory response and redox imbalance. In addition, pioneering evidences established the ability of arsenic to induce an up regulation of Hsp90, eventually resulting in stabilization of its client protein Beclin-1, an important autophagy-initiating factor. This association initiated the autophagic process, confirmed by co-immunoprecipitation assay, acridine orange staining and Western blot, indicating the effort of cells trying to survive at lower doses. However, increased arsenic assault led to apoptotic cell death in the lymphoid organs, possibly by increased ROS generation. There are several instances of autophagy and apoptosis taking place either simultaneously or sequentially due to oxidative stress. Since arsenic is a potent environmental stress factor, exposure to arsenic led to a dose-dependent increase in both autophagy and apoptosis in the thymus and spleen, and cell death could therefore possibly be induced by autophagy. Therefore, exposure to arsenic leads to serious effects on the immune physiology in mice, which may further have dire consequences on the health of exposed animals.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124647DOI Listing
January 2020

Modulating EGFR-MTORC1-autophagy as a potential therapy for persistent fetal vasculature (PFV) disease.

Autophagy 2020 06 1;16(6):1130-1142. Epub 2019 Sep 1.

Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine , Pittsburgh, PA, USA.

Persistent fetal vasculature (PFV) is a human disease that results from failure of the fetal vasculature to regress normally. The regulatory mechanisms responsible for fetal vascular regression remain obscure, as does the underlying cause of regression failure. However, there are a few animal models that mimic the clinical manifestations of human PFV, which can be used to study different aspects of the disease. One such model is the Nuc1 rat model that arose from a spontaneous mutation in the (crystallin, beta 1) gene and exhibits complete failure of the hyaloid vasculature to regress. Our studies with the Nuc1 rat indicate that macroautophagy/autophagy, a process in eukaryotic cells for degrading dysfunctional components to ensure cellular homeostasis, is severely impaired in Nuc1 ocular astrocytes. Further, we show that CRYBA1 interacts with EGFR (epidermal growth factor receptor) and that loss of this interaction in Nuc1 astrocytes increases EGFR levels. Moreover, our data also show a reduction in EGFR degradation in Nuc1 astrocytes compared to control cells that leads to over-activation of the mechanistic target of rapamycin kinase complex 1 (MTORC1) pathway. The impaired EGFR-MTORC1-autophagy signaling in Nuc1 astrocytes triggers abnormal proliferation and migration. The abnormally migrating astrocytes ensheath the hyaloid artery, contributing to the pathogenesis of PFV in Nuc1, by adversely affecting the vascular remodeling processes essential to regression of the fetal vasculature. Herein, we demonstrate that gefitinib (EGFR inhibitor) can rescue the PFV phenotype in Nuc1 and may serve as a novel therapy for PFV disease by modulating the EGFR-MTORC1-autophagy pathway.

Abbreviations: ACTB: actin, beta; CCND3: cyclin 3; CDK6: cyclin-dependent kinase 6; CHQ: chloroquine; COL4A1: collagen, type IV, alpha 1; CRYBA1: crystallin, beta A1; DAPI: 4'6-diamino-2-phenylindole; EGFR: epidermal growth factor receptor; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFAP: glial fibrillary growth factor; KDR: kinase insert domain protein receptor; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MKI67: antigen identified by monoclonal antibody Ki 67; MTORC1: mechanistic target of rapamycin kinase complex 1; PARP: poly (ADP-ribose) polymerase family; PCNA: proliferating cell nuclear antigen; PFV: persistent fetal vasculature; PHPV: persistent hyperplastic primary vitreous; RPE: retinal pigmented epithelium; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase, polypeptide 1; SQSTM1/p62: sequestome 1; TUBB: tubulin, beta; VCL: vinculin; VEGFA: vascular endothelial growth factor A; WT: wild type.
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http://dx.doi.org/10.1080/15548627.2019.1660545DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469569PMC
June 2020

Dietary pomegranate supplement alleviates murine pancreatitis by modulating Nrf2-p21 interaction and controlling apoptosis to survival switch.

J Nutr Biochem 2019 04 21;66:17-28. Epub 2018 Dec 21.

Department of Physiology, University of Calcutta, UCSTA, 92, A.P.C. Road, Kolkata, 700009, West Bengal, India. Electronic address:

Dietary supplementation of polyphenol-rich pomegranate extract (POMx) has been shown to have anti-oxidant and anti-inflammatory activities. Here, we evaluate the efficacy of POMx in mitigating pancreatitis in mice and provide a mechanistic outline of the process. Age-matched male Swiss albino mice were injected with Lipopolysaccharide (LPS) and given POMx supplement alone or in combination with LPS. After 4 weeks of treatment histological scoring for pancreatic edema and vacuolization was performed. Serum insulin levels were estimated and the glucose tolerance test (IPGTT) data revealed that POMx reduced inflammation induced hyperglycemia in mice. Analysis of TLR4, IκB expression, and NF-κB nuclear translocation, and concentrations of IL-6 and TNFα showed that POMx is able to modulate the molecular instigators of inflammatory responses. Annexin V assay indicated that POMx protects against inflammation-mediated apoptosis in the pancreas. Expression profile of SAPK/JNK pathway, p53, Bax, Bcl-2 and Caspase-3 validate an apoptotic to survival shift in POMx treatment group. Co-immunoprecipitation studies show that POMx stabilizes p21 and Nrf2 interaction and increases its nuclear translocation. The study also proves that the nuclear fraction of Nrf2 is able to bind to the Bcl-2 promoter and activate an anti-apoptotic program. The findings of our study underline an anti-inflammatory, anti-oxidative and anti-apoptotic role of POMx and provide a mechanistic idea of how POMx confers protection during pancreatitis.
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http://dx.doi.org/10.1016/j.jnutbio.2018.12.009DOI Listing
April 2019

Fluoxetine triggers selective apoptosis in inflammation-induced proliferating (Ki-67 ) thymocytes.

Immunol Cell Biol 2019 05 14;97(5):470-484. Epub 2019 Feb 14.

Department of Physiology, University of Calcutta, UCSTA, 92, Acharya Prafulla Chandra Road, 700009, Kolkata, India.

Inappropriate functioning of the immune system is observed during sustained systemic inflammation, which might lead to immune deficiencies, autoimmune disorders and cancer. Primary lymphoid organs may progress to a deregulated proliferative state in response to inflammatory signals in order to intensify host defense mechanisms and exacerbate an inflammatory niche. Fluoxetine, a selective serotonin reuptake inhibitor, has recently been projected as an anti-inflammatory agent. This study had been designed to evaluate the potential novel role of fluoxetine in reversing inflammation-induced immune dysfunction. Lipopolysaccharide (LPS) administration in Swiss albino mice potentiated a systemic inflammatory response, along with increased proliferation of thymocytes and peripheral blood mononuclear cells, as evident from increased Ki-67 expression. The proliferative changes in the immune system were mainly associated with increased phosphorylation of PI3k, AKT and IκB along with elevated NFκB-p65 nuclear translocation. The Ki-67 thymocytes obtained from LPS administered mice demonstrated significantly low p53 nuclear activity, which was established to be mediated by NFκB through reduced nuclear translocation of p53 during LPS-induced proliferative conditions, thereby blocking p53-dependent apoptosis. Fluoxetine supplementation not only reversed the proinflammatory condition, but also induced selective apoptosis in the proliferation-dictated Ki-67 thymocytes possibly by modulating the hypothalamus-pituitary-adrenal axis and inducing glucocorticoid receptor activation and apoptosis in these proliferation-biased immune cells, authenticating a novel antiproliferative role of an established drug.
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http://dx.doi.org/10.1111/imcb.12227DOI Listing
May 2019

A Role for βA3/A1-Crystallin in Type 2 EMT of RPE Cells Occurring in Dry Age-Related Macular Degeneration.

Invest Ophthalmol Vis Sci 2018 03;59(4):AMD104-AMD113

Glia Research Laboratory, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.

Purpose: The RPE cells have a major role in the development of dry age-related macular degeneration (AMD). We present novel evidence that βA3/A1-crystallin, encoded by the Cryba1 gene, a protein known to be important for lysosomal clearance in the RPE, also has a role in epithelial-to-mesenchymal transition (EMT) of RPE cells.

Methods: RPE from dry AMD globes, genetically engineered mice lacking Cryba1 globally or specifically in the RPE, spontaneous mutant rats (Nuc1) with a loss-of-function mutation in Cryba1, and the melanoma OCM3 cell line were used. Spatial localization of proteins was demonstrated with immunofluorescence, gene expression levels were determined by quantitative PCR (qPCR), and protein levels by Western blotting. Cell movement was evaluated using wound healing and cell migration assays. Co-immunoprecipitation was used to identify binding partners of βA3/A1-crystallin.

Results: βA3/A1-crystallin is upregulated in polarized RPE cells compared to undifferentiated cells. Loss of βA3/A1-crystallin in murine and human RPE cells resulted in upregulation of Snail and vimentin, downregulation of E-cadherin, and increased cell migration. βA3/A1-crystallin binds to cortactin, and loss of βA3/A1-crystallin resulted in increased P-cortactinY421. The RPE from AMD samples had increased Snail and vimentin, and decreased E-cadherin, compared to age-matched controls.

Conclusions: We introduced a novel concept of dry AMD initiation induced by lysosomal clearance defects in the RPE and subsequent attempts by RPE cells to avoid the resulting stress by undergoing EMT. We demonstrate that βA3/A1-crystallin is a potential therapeutic target for AMD through rejuvenation of lysosomal dysfunction and potentially, reversal of EMT.
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http://dx.doi.org/10.1167/iovs.18-24132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6058694PMC
March 2018

The amino acid transporter SLC36A4 regulates the amino acid pool in retinal pigmented epithelial cells and mediates the mechanistic target of rapamycin, complex 1 signaling.

Aging Cell 2017 04 13;16(2):349-359. Epub 2017 Jan 13.

The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.

The dry (nonneovascular) form of age-related macular degeneration (AMD), a leading cause of blindness in the elderly, has few, if any, treatment options at present. It is characterized by early accumulation of cellular waste products in the retinal pigmented epithelium (RPE); rejuvenating impaired lysosome function in RPE is a well-justified target for treatment. It is now clear that amino acids and vacuolar-type H -ATPase (V-ATPase) regulate the mechanistic target of rapamycin, complex 1 (mTORC1) signaling in lysosomes. Here, we provide evidence for the first time that the amino acid transporter SLC36A4/proton-dependent amino acid transporter (PAT4) regulates the amino acid pool in the lysosomes of RPE. In Cryba1 (gene encoding βA3/A1-crystallin) KO (knockout) mice, where PAT4 and amino acid levels are increased in the RPE, the transcription factors EB (TFEB) and E3 (TFE3) are retained in the cytoplasm, even after 24 h of fasting. Consequently, genes in the coordinated lysosomal expression and regulation (CLEAR) network are not activated, and lysosomal function remains low. As these mice age, expression of RPE65 and lecithin retinol acyltransferase (LRAT), two vital visual cycle proteins, decreases in the RPE. A defective visual cycle would possibly slow down the regeneration of new photoreceptor outer segments (POS). Further, photoreceptor degeneration also becomes obvious during aging, reminiscent of human dry AMD disease. Electron microscopy shows basal laminar deposits in Bruch's membrane, a hallmark of development of AMD. For dry AMD patients, targeting PAT4/V-ATPase in the lysosomes of RPE cells may be an effective means of preventing or delaying disease progression.
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http://dx.doi.org/10.1111/acel.12561DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334531PMC
April 2017

Activating the AKT2-nuclear factor-κB-lipocalin-2 axis elicits an inflammatory response in age-related macular degeneration.

J Pathol 2017 04 20;241(5):583-588. Epub 2017 Feb 20.

Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Age-related macular degeneration (AMD) is a complex and progressive degenerative eye disease resulting in severe loss of central vision. Recent evidence indicates that immune system dysregulation could contribute to the development of AMD. We hypothesize that defective lysosome-mediated clearance causes accumulation of waste products in the retinal pigmented epithelium (RPE), activating the immune system and leading to retinal tissue injury and AMD. We have generated unique genetically engineered mice in which lysosome-mediated clearance (both by phagocytosis and autophagy) in RPE cells is compromised, causing the development of features of early AMD. Our recent data indicate a link between lipocalin-2 (LCN-2) and the inflammatory responses induced in this mouse model. We show that nuclear factor-κB (NF-κB) and STAT-1 may function as a complex in our animal model system, together controlling the upregulation of LCN-2 expression in the retina and stimulating an inflammatory response. This study revealed increased infiltration of LCN-2-positive neutrophils in the choroid and retina of early AMD patients as compared with age-matched controls. Our results demonstrate that, both in our animal model and in human AMD, the AKT2-NF-κB-LCN-2 signalling axis is involved in activating the inflammatory response, making this pathway a potential target for AMD treatment. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/path.4870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357190PMC
April 2017

Pomegranate protects against arsenic-induced p53-dependent ROS-mediated inflammation and apoptosis in liver cells.

J Nutr Biochem 2016 12 6;38:25-40. Epub 2016 Sep 6.

Department of Physiology, University of Calcutta, UCSTA, 92, Acharya Prafulla Chandra Road, Kolkata 700009, India; Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Salt Lake, Sector III, Kolkata 700098, India. Electronic address:

Molecular mechanisms involved in arsenic-induced toxicity are complex and elusive. Liver is one of the most favored organs for arsenic toxicity as methylation of arsenic occurs mostly in the liver. In this study, we have selected a range of environmentally relevant doses of arsenic to examine the basis of arsenic toxicity and the role of pomegranate fruit extract (PFE) in combating it. Male Swiss albino mice exposed to different doses of arsenic presented marked hepatic injury as evident from histological and electron microscopic studies. Increased activities of enzymes alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatase corroborated extensive liver damage. It was further noted that arsenic exposure initiated reactive oxygen species (ROS)-dependent apoptosis in the hepatocytes involving loss of mitochondrial membrane potential. Arsenic significantly increased nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB), coupled with increase in phosphorylated Iκ-B, possibly as adaptive cellular survival strategies. Arsenic-induced oxidative DNA damage to liver cells culminated in p53 activation and increased expression of p53 targets like miR-34a and Bax. Pomegranate polyphenols are known to possess remarkable antioxidant properties and are capable of protecting normal cells from various stimuli-induced oxidative stress and toxicities. We explored the protective role of PFE in ameliorating arsenic-induced hepatic damage. PFE was shown to reduce ROS generation in hepatocytes, thereby reducing arsenic-induced Nrf2 activation. PFE also inhibited arsenic-induced NF-κB-inflammatory pathway. Data revealed that PFE reversed arsenic-induced hepatotoxicity and apoptosis by modulating the ROS/Nrf2/p53-miR-34a axis. For the first time, we have mapped the possible signaling pathways associated with arsenic-induced hepatotoxicity and its rescue by pomegranate polyphenols.
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http://dx.doi.org/10.1016/j.jnutbio.2016.09.001DOI Listing
December 2016

Arsenic-induced dose-dependent modulation of the NF-κB/IL-6 axis in thymocytes triggers differential immune responses.

Toxicology 2016 05 8;357-358:85-96. Epub 2016 Jun 8.

Department of Physiology, UCSTA, University of Calcutta, 92, A.P.C. Road, Kolkata 700009, India. Electronic address:

Arsenic contamination of drinking water is a matter of global concern. Arsenic intake impairs immune responses and leads to a variety of pathological conditions including cancer. In order to understand the intricate tuning of immune responses elicited by chronic exposure to arsenic, a mouse model was established by subjecting mice to different environmentally relevant concentrations of arsenic in drinking water for 30days. Detailed study of the thymus, a primary immune organ, revealed arsenic-mediated tissue damage in both histological specimens and scanning electron micrographs. Analysis of molecular markers of apoptosis by Western blot revealed a dose-dependent activation of the apoptotic cascade. Enzymatic assays supported oxidative stress as an instigator of cell death. Interestingly, assessment of inflammatory responses revealed disparity in the NF-κB/IL-6/STAT3 axis, where it was found that in animals consuming higher amounts of arsenic NF-κB activation did not lead to the classical IL-6 upregulation response. This deviation from the canonical pathway was accompanied with a significant rise in numbers of CD4+ CD25+ FoxP3 expressing cells in the thymus. The cytokine profile of the animals exposed to higher doses of arsenic also indicated an immune-suppressed milieu, thus validating that arsenic shapes the immune environment in context to its dose of exposure and that at higher doses it leads to immune-suppression. Our study establishes a novel role of arsenic in regulating immune homeostasis in context to its dose, where, at higher doses, arsenic related upregulation of NF-κB cascade takes on an alternative role that is correlated with increased immune-suppression.
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http://dx.doi.org/10.1016/j.tox.2016.06.005DOI Listing
May 2016

Gold-conjugated green tea nanoparticles for enhanced anti-tumor activities and hepatoprotection--synthesis, characterization and in vitro evaluation.

J Nutr Biochem 2015 Nov 26;26(11):1283-97. Epub 2015 Jul 26.

Department of Physiology, University of Calcutta; UCSTA, 92, Acharya Prafulla Chandra Road, Kolkata-700009, India; Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Salt Lake, Sector III, Kolkata-700098, India. Electronic address:

Green tea (GT)-based chemoprevention has shown promising results in various cancer models. However, the effective dose may not be far from the toxic dose because of inefficient systemic delivery and limited bio-availability of GT polyphenols. We have used GT polyphenols to successfully reduce gold to corresponding gold nanoparticles (NPs) in a single step; a process that fulfils all criteria of green nanotechnology as no "man-made" chemical other than gold acids are used. GT and (-) - epigallocatechin-3-gallate (EGCG) conjugated gold NPs (diameters <50 nm), showed remarkable stability, significantly rapid cellular uptake and excellent in vitro anti-oxidant activities. These NPs were observed to be selectively toxic towards cancer cells (Ehrlich's Ascites Carcinoma and MCF-7) while showing absolutely no lethality towards normal primary mouse hepatocytes. In cancer cells, NPs altered the redox status and limited Nrf2 activation by almost 50%. These NPs significantly decreased nuclear translocation of NF-κB, coupled with decreased phosphorylation of IĸB and down-regulation of NF-κB-dependent anti-apoptotic proteins Bcl2 and Akt in a dose-dependent manner, triggering onset of apoptosis. Culturing normal hepatocytes with tumor-conditioned media prompted apoptosis by increasing reactive oxygen species (ROS) and depleting the anti-oxidant defense mechanism of hepatocytes. Pre-treatment with NPs protected hepatocytes from tumor-induced cellular damage by scavenging excess ROS, increasing the levels of reduced glutathione and anti-oxidant enzymes. There was evidence of decreased Bax/Bcl2 ratio and active Caspase 3 levels in these hepatocytes, indicating apoptosis escape. Nanoformulations of GT-based polyphenols might serve as an operative platform for effective delivery, increased bio-availability, enhanced effects and minimal chemotherapy-associated toxicities.
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http://dx.doi.org/10.1016/j.jnutbio.2015.06.003DOI Listing
November 2015

Reactive oxygen species in the tumor niche triggers altered activation of macrophages and immunosuppression: Role of fluoxetine.

Cell Signal 2015 Jul 27;27(7):1398-412. Epub 2015 Mar 27.

Department of Physiology, University of Calcutta, UCSTA, 92, Acharya Prafulla Chandra Road, Kolkata-700009, India; Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Salt Lake, Sector III, Kolkata-700098, India. Electronic address:

Macrophages are projected as one of the key players responsible for the progression of cancer. Classically activated (M1) macrophages are pro-inflammatory and have a central role in host defense, while alternatively activated (M2) macrophages are associated with immunosuppression. Macrophages residing at the site of neoplastic growth are alternately activated and are referred to as tumor-associated macrophages (TAMs). These "cooperate" with tumor tissue, promoting increased proliferation and immune escape. Selective serotonin reuptake inhibitors like fluoxetine have recently been reported to possess anti-inflammatory activity. We used fluoxetine to target tumor-associated inflammation and consequent alternate polarization of macrophages. We established that murine peritoneal macrophages progressed towards an altered activation state when exposed to cell-free tumor fluid, as evidenced by increased IL-6, IL-4 and IL-10 levels. These polarized macrophages showed significant pro-oxidant bias and increased p65 nuclear localization. It was further observed that these altered macrophages could induce oxidative insult and apoptosis in cultured mouse CD3(+) T cells. To validate these findings, we replicated key experiments in vivo, and observed that there was increased serum IL-6, IL-4 and IL-10 in tumor-bearing animals, with increased % CD206(+) cells within the tumor niche. TAMs showed increased nuclear localization of p65 with decreased Nrf2 expression in the nucleus. These results were associated with increase in apoptosis of CD3(+) T cells co-cultured with TAM-spent media. We could establish that fluoxetine treatment could specifically re-educate the macrophages both in vitro and in vivo by skewing their phenotype such that immune suppression mediated by tumor-dictated macrophages was successfully mitigated.
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http://dx.doi.org/10.1016/j.cellsig.2015.03.013DOI Listing
July 2015

Protective effect of coconut water concentrate and its active component shikimic acid against hydroperoxide mediated oxidative stress through suppression of NF-κB and activation of Nrf2 pathway.

J Ethnopharmacol 2014 Aug 14;155(1):132-46. Epub 2014 May 14.

ICMR Virus Unit, ID & BG Hospital, GB-4, First Floor, 57 Dr. Suresh C Banerjee Road, Beliaghata, Kolkata 700010, West Bengal, India.

Ethnopharmacological Relevance: Conventionally coconut water has been used as an 'excellent hydrating' drink that maintain the electrolyte balance and help in treating diverse ailments related to oxidative stress including liver function. The present study was aimed to elucidate whether and how the coconut water concentrate (CWC) and its major active phytoconstituent shikimic acid (SA) can effectively protect murine hepatocytes from the deleterious effect of hydroperoxide-mediated oxidative stress.

Materials And Methods: Bioactivity guided fractionation of CWC resulted in the isolation of a couple of known compounds. Freshly isolated murine hepatocytes were exposed to hydrogen peroxide (H2O2) (1 and 3mM) in the presence or absence of CWC (200 and 400 μg/ml) and SA (40 μM) for the determination of antioxidative, DNA protective, cellular ROS level by modern methods, including immunoblot and flowcytometry to find out the possible mechanism of action.

Results: Pre-treatment of hepatocyte with CWC and SA showed significant prevention of H2O2-induced intracellular ROS generation, nuclear DNA damage along with the formation of hepatic TBARS and cellular nitrite. Further, the H2O2 induced cell death was arrested in the presence of CWC through the inhibition of CDC42 mediated SAPK/JNK pathways and activation of other molecules of apoptotic pathways, including Bax and caspase3. Moreover, CWC and SA help in maintaining the GSH level and endogenous antioxidants like Mn-SOD, to support intracellular defense mechanisms, probably through the transcriptional activation of Nrf2; and inhibition of nuclear translocation of NF-κB.

Conclusion: CWC and its active components SA reversed the H2O2 induced oxidative damage in hepatocytes, probably through the inhibition of NF-κB, with the activation of PI3K/Akt/Nrf2 pathway and reduction of apoptosis by interfering the SAPK/JNK/Bax pathway.
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http://dx.doi.org/10.1016/j.jep.2014.04.046DOI Listing
August 2014

Pomegranate reverses methotrexate-induced oxidative stress and apoptosis in hepatocytes by modulating Nrf2-NF-κB pathways.

J Nutr Biochem 2013 Dec;24(12):2040-50

Department of Physiology, University of Calcutta, Kolkata, West Bengal 700009, India.

The clinical efficacy of the widely used chemotherapeutic drug methotrexate (MTX) is limited due to its associated hepatotoxicity. Pomegranate polyphenols are of huge health benefits and known to possess remarkable antioxidant properties capable of protecting normal cells from various stimuli-induced oxidative stress and cell death. In this study, we explored the protective role of pomegranate fruit extract (PFE) in ameliorating MTX-induced hepatic damage. Male Swiss albino mice exposed to MTX (20 mg/kg body weight) exhibited distinct markers of toxicity such as increased activities of enzymes alanine transaminase, aspartate transaminase, lactate dehydrogenase and alkaline phosphatase and also increased oxidative stress in liver evidenced by increased ROS generation and lipid peroxidation. Decrease in reduced glutathione levels, superoxide dismutase, catalase, hepatic heme oxygenase 1 and NQO-1 activities were also observed. Tracing the signal transduction pathways, it was seen that MTX exposure significantly increased nuclear translocation of NF-κB coupled with increase in phosphorylated Iκ-B and down-regulation of NF-kappaB-dependent antiapoptotic protein Bcl-2. Treatment with MTX increased the expression of the apoptotic enhancer Rho/Cdc42 as well as the phosphorylation of SAPK/JNK. A shift in the Bax/Bcl-2 ratio towards apoptosis and increase in the caspase 3 level was also evident. Administration of PFE for 7 consecutive days before and after MTX challenge suppressed MTX-induced cell death, mitigated the injurious effects of MTX and offered protection against apoptosis. PFE was shown to reduce ROS generation in hepatocytes by activating the Nrf2-ARE pathway and inhibiting NF-κB as a consequence of which the antioxidant defense mechanism in the liver was up-regulated, thereby conferring protection against MTX-induced hepatotoxicity and apoptosis.
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http://dx.doi.org/10.1016/j.jnutbio.2013.07.005DOI Listing
December 2013

Modafinil improves event related potentials P300 and contingent negative variation after 24 h sleep deprivation.

Life Sci 2012 Aug 28;91(3-4):94-9. Epub 2012 Jun 28.

Neurophysiology Division, Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi, 110054, India.

Aims: The efficacy of modafinil as a countermeasure in the reduction of cognitive decline following 24 h of sleep deprivation (SD) on subjective sleepiness scales, event-related potential (ERP) P300, and contingent negative variation (CNV) was evaluated.

Main Methods: Eleven healthy males, age 25-30 years participated. The experiment was performed in five sessions on different days between 7 and 8a.m. Session 1, baseline recordings; Session 2, after one night's SD; Session 3, 48 h of recovery from SD; Session 4, after 1 week of Session 1, following one night's SD along with modafinil (400mg/day); Session 5, 48 h of recovery after SD+modafinil.

Key Findings: Subjective sleepiness scores increased significantly after SD as compared to baseline (P<0.01), but remained unaltered after modafinil supplementation. There was an increase in N100 and P300 peak latencies of ERP following SD (P<0.01), which was reduced with modafinil (P<0.05). There was an increase in CNV M100 and P300 peak latencies after SD (P<0.01) which decreased with the use of modafinil (P<0.05). The CNV reaction time increased following SD (P<0.01) and decreased with the use of modafinil (P<0.05). No significant effects on ERP N200, P200 latencies and P200, P300 amplitudes and CNV N100, M200 peak latencies and M100, M200 amplitudes were observed.

Significance: The results strongly suggest that modafinil in a dose of 400mg/day, reduces the subjective sleepiness and cognitive decline following 24 h of SD.
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http://dx.doi.org/10.1016/j.lfs.2012.06.012DOI Listing
August 2012

On convergence of differential evolution over a class of continuous functions with unique global optimum.

IEEE Trans Syst Man Cybern B Cybern 2012 Feb 25;42(1):107-24. Epub 2011 Jul 25.

Indian Institute of Science Bangalore, Bangalore 560 012, India.

Differential evolution (DE) is arguably one of the most powerful stochastic real-parameter optimization algorithms of current interest. Since its inception in the mid 1990s, DE has been finding many successful applications in real-world optimization problems from diverse domains of science and engineering. This paper takes a first significant step toward the convergence analysis of a canonical DE (DE/rand/1/bin) algorithm. It first deduces a time-recursive relationship for the probability density function (PDF) of the trial solutions, taking into consideration the DE-type mutation, crossover, and selection mechanisms. Then, by applying the concepts of Lyapunov stability theorems, it shows that as time approaches infinity, the PDF of the trial solutions concentrates narrowly around the global optimum of the objective function, assuming the shape of a Dirac delta distribution. Asymptotic convergence behavior of the population PDF is established by constructing a Lyapunov functional based on the PDF and showing that it monotonically decreases with time. The analysis is applicable to a class of continuous and real-valued objective functions that possesses a unique global optimum (but may have multiple local optima). Theoretical results have been substantiated with relevant computer simulations.
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http://dx.doi.org/10.1109/TSMCB.2011.2160625DOI Listing
February 2012

Multi-objective differential evolution for automatic clustering with application to micro-array data analysis.

Sensors (Basel) 2009 25;9(5):3981-4004. Epub 2009 May 25.

Dept. of Electronics and Telecommunication Engg, Jadavpur University, Kolkata, India; E-Mails: ; ; ;

This paper applies the Differential Evolution (DE) algorithm to the task of automatic fuzzy clustering in a Multi-objective Optimization (MO) framework. It compares the performances of two multi-objective variants of DE over the fuzzy clustering problem, where two conflicting fuzzy validity indices are simultaneously optimized. The resultant Pareto optimal set of solutions from each algorithm consists of a number of non-dominated solutions, from which the user can choose the most promising ones according to the problem specifications. A real-coded representation of the search variables, accommodating variable number of cluster centers, is used for DE. The performances of the multi-objective DE-variants have also been contrasted to that of two most well-known schemes of MO clustering, namely the Non Dominated Sorting Genetic Algorithm (NSGA II) and Multi-Objective Clustering with an unknown number of Clusters K (MOCK). Experimental results using six artificial and four real life datasets of varying range of complexities indicate that DE holds immense promise as a candidate algorithm for devising MO clustering schemes.
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http://dx.doi.org/10.3390/s90503981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3297137PMC
September 2012
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