Dysregulated cholinergic signaling inhibits oligodendrocyte maturation following demyelination.

Dysregulation of oligodendrocyte progenitor cell (OPC) recruitment and oligodendrocyte differentiation contribute to failure of remyelination in human demyelinating diseases such as multiple sclerosis (MS). Deletion of muscarinic receptor enhances OPC differentiation and remyelination. However, the role of ligand-dependent signaling versus constitutive receptor activation is unknown. We hypothesized that dysregulated acetylcholine (ACh) release upon demyelination contributes to ligand mediated activation hindering myelin repair. Following chronic cuprizone induced demyelination (male and female mice), we observed a 2.5-fold increase in ACh concentration. This increase in ACh concentration could be attributed to increased ACh synthesis or decreased acetylcholinesterase (AChE) / butyrylcholinesterase (BChE) mediated degradation. Using ChAT reporter mice, we identified increased ChAT-GFP expression following both lysolecithin and cuprizone demyelination. ChAT-GFP expression was upregulated in a subset of injured and uninjured axons following intraspinal lysolecithin induced demyelination. In cuprizone demyelinated corpus callosum, ChAT-GFP was observed in Gfap+ astrocytes and axons indicating the potential for neuronal and astrocytic ACh release. BChE expression was significantly decreased in the corpus callosum following cuprizone demyelination. This decrease was due to the loss of myelinating oligodendrocytes which were the primary source of BChE. To determine the role of ligand mediated muscarinic signaling following lysolecithin injection, we administered neostigmine, a cholinesterase inhibitor, to artificially raise ACh. We identified a dose-dependent decrease in mature oligodendrocyte density with no effect on OPC recruitment. Together, these results support a functional role of ligand mediated activation of muscarinic receptors following demyelination and suggest that dysregulation of ACh homeostasis directly contributes to failure of remyelination in MS.Significance Statement Demyelinating diseases like Multiple Sclerosis are characterized by failure of remyelination. Oligodendrocyte progenitor cell (OPC) recruitment and differentiation are crucial aspects for remyelination to occur. Here we show that increased acetylcholine (ACh) contributes to activation of muscarinic receptors that inhibit OPC differentiation. Increased choline acetyltransferase synthesis following demyelination was observed in axons and astrocytes suggestive of a potential for acetylcholine synthesis and release. The increase in ACh levels following demyelination was largely due to reduction of oligodendrocyte derived butyrylcholinesterase that modulates ACh concentration. Development of cell specific esterase stimulator to restore ACh levels may serve as an approach towards inhibiting ongoing demyelination and neurodegeneration.

Metabolomics of early blight (Alternaria solani) susceptible tomato (Solanum lycopersicum) unfolds key biomarker metabolites and involved metabolic pathways.

Tomato (Solanum lycopersicum) is among the most important commercial horticultural crops worldwide. The crop quality and production is largely hampered due to the fungal pathogen Alternaria solani causing necrotrophic foliage early blight disease. Crop plants usually respond to the biotic challenges with altered metabolic composition and physiological perturbations. We have deciphered altered metabolite composition, modulated metabolic pathways and identified metabolite biomarkers in A. solani-challenged susceptible tomato variety Kashi Aman using Liquid Chromatography-Mass Spectrometry (LC-MS) based metabolomics. Alteration in the metabolite feature composition of pathogen-challenged (m/z 9405) and non-challenged (m/z 9667) plant leaves including 8487 infection-exclusive and 8742 non-infection exclusive features was observed. Functional annotation revealed putatively annotated metabolites and pathway mapping indicated their enrichment in metabolic pathways, biosynthesis of secondary metabolites, ubiquinone and terpenoid-quinones, brassinosteroids, steroids, terpenoids, phenylpropanoids, carotenoids, oxy/sphingolipids and metabolism of biotin and porphyrin. PCA, multivariate PLS-DA and OPLS-DA analysis showed sample discrimination. Significantly up regulated 481 and down regulated 548 metabolite features were identified based on the fold change (threshold ≥ 2.0). OPLS-DA model based on variable importance in projection (VIP scores) and FC threshold (> 2.0) revealed 41 up regulated discriminant metabolite features annotated as sphingosine, fecosterol, melatonin, serotonin, glucose 6-phosphate, zeatin, dihydrozeatin and zeatin-ß-D-glucoside. Similarly, 23 down regulated discriminant metabolites included histidinol, 4-aminobutyraldehyde, propanoate, tyramine and linalool. Melatonin and serotonin in the leaves were the two indoleamines being reported for the first time in tomato in response to the early blight pathogen. Receiver operating characteristic (ROC)-based biomarker analysis identified apigenin-7-glucoside, uridine, adenosyl-homocysteine, cGMP, tyrosine, pantothenic acid, riboflavin (as up regulated) and adenosine, homocyctine and azmaline (as down regulated) biomarkers. These results could aid in the development of metabolite-quantitative trait loci (mQTL). Furthermore, stress-induced biosynthetic pathways may be the potential targets for modifications through breeding programs or genetic engineering for improving crop performance in the fields.

Dicer deficiency in microglia leads to accelerated demyelination and failed remyelination.

Microglia are the resident immune cells of the central nervous system (CNS) and are important regulators of normal brain functions. In CNS demyelinating diseases like multiple sclerosis (MS), the functions of these cells are of particular interest. Here we probed the impact of microRNA (miRNA)-mediated post-transcriptional gene regulation using a mouse model lacking microglia/macrophage-specific Dicer expression during demyelination and remyelination. Conditional Dicer ablation and loss of miRNAs in adult microglia led to extensive demyelination and impaired myelin processing. Interestingly, demyelination was accompanied by increased apoptosis of mature oligodendrocytes (OLs) and arresting OL progenitor cells (OPCs) in the precursor stage. At the transcriptional level, Dicer -deficient microglia led to downregulation of microglial homeostatic genes, increased cell proliferation, and a shift towards a disease-associated phenotype. Loss of remyelination efficiency in these mice was accompanied by stalling of OPCs in the precursor stage. Collectively, these results highlight a new role of microglial miRNAs in promoting a pro-regenerative phenotype in addition to promoting OPC maturation and differentiation during demyelination and remyelination.

Untargeted Metabolomics of Alternaria solani-Challenged Wild Tomato Species Solanum cheesmaniae Revealed Key Metabolite Biomarkers and Insight into Altered Metabolic Pathways.

Untargeted metabolomics of moderately resistant wild tomato species Solanum cheesmaniae revealed an altered metabolite profile in plant leaves in response to Alternaria solani pathogen. Leaf metabolites were significantly differentiated in non-stressed versus stressed plants. The samples were discriminated not only by the presence/absence of specific metabolites as distinguished markers of infection, but also on the basis of their relative abundance as important concluding factors. Annotation of metabolite features using the Arabidopsis thaliana (KEGG) database revealed 3371 compounds with KEGG identifiers belonging to biosynthetic pathways including secondary metabolites, cofactors, steroids, brassinosteroids, terpernoids, and fatty acids. Annotation using the Solanum lycopersicum database in PLANTCYC PMN revealed significantly upregulated (541) and downregulated (485) features distributed in metabolite classes that appeared to play a crucial role in defense, infection prevention, signaling, plant growth, and plant homeostasis to survive under stress conditions. The orthogonal partial least squares discriminant analysis (OPLS-DA), comprising a significant fold change (≥2.0) with VIP score (≥1.0), showed 34 upregulated biomarker metabolites including 5-phosphoribosylamine, kaur-16-en-18-oic acid, pantothenate, and O-acetyl-L-homoserine, along with 41 downregulated biomarkers. Downregulated metabolite biomarkers were mapped with pathways specifically known for plant defense, suggesting their prominent role in pathogen resistance. These results hold promise for identifying key biomarker metabolites that contribute to disease resistive metabolic traits/biosynthetic routes. This approach can assist in mQTL development for the stress breeding program in tomato against pathogen interactions.

IFN-Induced Protein with Tetratricopeptide Repeats 2 Limits Autoimmune Inflammation by Regulating Myeloid Cell Activation and Metabolic Activity.

Besides antiviral functions, type I IFN expresses potent anti-inflammatory properties and is being widely used to treat certain autoimmune conditions, such as multiple sclerosis. In a murine model of multiple sclerosis, experimental autoimmune encephalomyelitis, administration of IFN-ß effectively attenuates the disease development. However, the precise mechanisms underlying IFN-ß-mediated treatment remain elusive. In this study, we report that IFN-induced protein with tetratricopeptide repeats 2 (Ifit2), a type I and type III IFN-stimulated gene, plays a previously unrecognized immune-regulatory role during autoimmune neuroinflammation. Mice deficient in Ifit2 displayed greater susceptibility to experimental autoimmune encephalomyelitis and escalated immune cell infiltration in the CNS. Ifit2 deficiency was also associated with microglial activation and increased myeloid cell infiltration. We also observed that myelin debris clearance and the subsequent remyelination were substantially impaired in Ifit2-/- CNS tissues. Clearing myelin debris is an important function of the reparative-type myeloid cell subset to promote remyelination. Indeed, we observed that bone marrow-derived macrophages, CNS-infiltrating myeloid cells, and microglia from Ifit2-/- mice express cytokine and metabolic genes associated with proinflammatory-type myeloid cell subsets. Taken together, our findings uncover a novel regulatory function of Ifit2 in autoimmune inflammation in part by modulating myeloid cell function and metabolic activity.

Molecular insights into mechanisms underlying thermo-tolerance in tomato.

Plant productivity is being seriously compromised by climate-change-induced temperature extremities. Agriculture and food safety are threatened due to global warming, and in many cases the negative impacts have already begun. Heat stress leads to significant losses in yield due to changes in growth pattern, plant phonologies, sensitivity to pests, flowering, grain filling, maturity period shrinkage, and senescence. Tomato is the second most important vegetable crop. It is very sensitive to heat stress and thus, yield losses in tomato due to heat stress could affect food and nutritional security. Tomato plants respond to heat stress with a variety of cellular, physiological, and molecular responses, beginning with the early heat sensing, followed by signal transduction, antioxidant defense, osmolyte synthesis and regulated gene expression. Recent findings suggest that specific plant organs are extremely sensitive to heat compared to the entire plant, redirecting the research more towards generative tissues. This is because, during sexual reproduction, developing pollens are the most sensitive to heat. Often, just a few degrees of temperature elevation during pollen development can have a negative effect on crop production. Furthermore, recent research has discovered certain genetic and epigenetic mechanisms playing key role in thermo-tolerance and have defined new directions for tomato heat stress response (HSR). Present challenges are to increase the understanding of molecular mechanisms underlying HS, and to identify superior genotypes with more tolerance to extreme temperatures. Several metabolites, genes, heat shock factors (HSFs) and microRNAs work together to regulate the plant HSR. The present review provides an insight into molecular mechanisms of heat tolerance and current knowledge of genetic and epigenetic control of heat-tolerance in tomato for sustainable agriculture in the future. The information will significantly contribute to improve breeding programs for development of heat tolerant cultivars.

Investigating NAC Transcription Factor Role in Redox Homeostasis in Solanum lycopersicum L.: Bioinformatics, Physiological and Expression Analysis under Drought Stress.

NAC transcription factors regulate stress-defence pathways and developmental processes in crop plants. However, their detailed functional characterization in tomatoes needs to be investigated comprehensively. In the present study, tomato hybrids subjected to 60 and 80 days of drought stress conditions showed a significant increase in membrane damage and reduced relative water, chlorophyll and proline content. However, hybrids viz., VRTH-16-3 and VRTH-17-68 showed superior growth under drought stress, as they were marked with low electrolytic leakage, enhanced relative water content, proline content and an enhanced activity of enzymatic antioxidants, along with the upregulation of NAC and other stress-defence pathway genes. Candidate gene(s) exhibiting maximum expression in all the hybrids under drought stress were subjected to detailed in silico characterization to provide significant insight into its structural and functional classification. The homology modelling and superimposition analysis of predicted tomato NAC protein showed that similar amino acid residues were involved in forming the conserved WKAT domain. DNA docking discovered that the SlNAC1 protein becomes activated and exerts a stress-defence response after the possible interaction of conserved DNA elements using Pro72, Asn73, Trp81, Lys82, Ala83, Thr84, Gly85, Thr86 and Asp87 residues. A protein-protein interaction analysis identified ten functional partners involved in the induction of stress-defence tolerance.

Metabolomics-Driven Mining of Metabolite Resources: Applications and Prospects for Improving Vegetable Crops.

Vegetable crops possess a prominent nutri-metabolite pool that not only contributes to the crop performance in the fields, but also offers nutritional security for humans. In the pursuit of identifying, quantifying and functionally characterizing the cellular metabolome pool, biomolecule separation technologies, data acquisition platforms, chemical libraries, bioinformatics tools, databases and visualization techniques have come to play significant role. High-throughput metabolomics unravels structurally diverse nutrition-rich metabolites and their entangled interactions in vegetable plants. It has helped to link identified phytometabolites with unique phenotypic traits, nutri-functional characters, defense mechanisms and crop productivity. In this study, we explore mining diverse metabolites, localizing cellular metabolic pathways, classifying functional biomolecules and establishing linkages between metabolic fluxes and genomic regulations, using comprehensive metabolomics deciphers of the plant's performance in the environment. We discuss exemplary reports covering the implications of metabolomics, addressing metabolic changes in vegetable plants during crop domestication, stage-dependent growth, fruit development, nutri-metabolic capabilities, climatic impacts, plant-microbe-pest interactions and anthropogenic activities. Efforts leading to identify biomarker metabolites, candidate proteins and the genes responsible for plant health, defense mechanisms and nutri-rich crop produce are documented. With the insights on metabolite-QTL (mQTL) driven genetic architecture, molecular breeding in vegetable crops can be revolutionized for developing better nutritional capabilities, improved tolerance against diseases/pests and enhanced climate resilience in plants.

Characterization of high-temperature stress-tolerant tomato (Solanum lycopersicum L.) genotypes by biochemical analysis and expression profiling of heat-responsive genes.

High-temperature stress severely impacts both yield and quality of tomato fruits, and therefore, it is required to develop stress-tolerant cultivars. In the present study, two tomato genotypes, H88-78-1 and CLN-1621, identified through preliminary phenotypic screening were characterized by analysis of molecular, physiological, and biochemical traits in comparison with a susceptible genotype Punjab Chhuhara. Phenotypic stress tolerance of both the genotypes was validated at biochemical level as they showed higher amount of relative water content, photosynthetic pigments, free cellular proline, and antioxidant molecules while less amount of H2O2 and electrolyte leakage. Expression analysis of 67 genes including heat shock factors, heat shock proteins, and other stress-responsive genes showed significant up-regulation of many of the genes such as 17.4 kDa class III heat shock protein, HSF A-4a, HSF30, HSF B-2a, HSF24, HSF B-3 like, 18.1 kDa class I HSP like, and HSP17.4 in H88-78-1 and CLN-1621 after exposure to high-temperature stress. These candidate genes can be transferred to cultivated varieties by developing gene-based markers and marker-assisted breeding. This confirms the rapid response of these genotypes to high-temperature stress. All these traits are characteristics of a stress-tolerance and establish them as candidate high-temperature stress-tolerant genotypes that can be effectively utilized in stress tolerance improvement programs. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-020-02587-6.

Comparative Proteomic Profiling Identifies Reciprocal Expression of Mitochondrial Proteins Between White and Gray Matter Lesions From Multiple Sclerosis Brains.

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system, where ongoing demyelination and remyelination failure are the major factors for progressive neurological disability. In this report, we employed a comprehensive proteomic approach and immunohistochemical validation to gain insight into the pathobiological mechanisms that may be associated with the progressive phase of MS. Isolated proteins from myelinated regions, demyelinated white-matter lesions (WMLs), and gray-matter lesions (GMLs) from well-characterized progressive MS brain tissues were subjected to label-free quantitative mass spectrometry. Using a system-biology approach, we detected increased expression of proteins belonging to mitochondrial electron transport complexes and oxidative phosphorylation pathway in WMLs. Intriguingly, many of these proteins and pathways had opposite expression patterns and were downregulated in GMLs of progressive MS brains. A comparison to the human MitoCarta database mapped the mitochondrial proteins to mitochondrial subunits in both WMLs and GMLs. Taken together, we provide evidence of opposite expression of mitochondrial proteins in response to demyelination of white- and gray-matter regions in progressive MS brain.

Consequences of chemical impact of disinfectants: safe preventive measures against COVID-19.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has created a significant threat to global health. It originated in Wuhan, China and caused a total of 83,483 confirmed cases and 4634 deaths until June 2020. This novel virus spread primarily through respiratory droplets and close contact. The person-to-person transmission by direct transmittance through cough, sneeze, droplet inhalation, and contact spreading from dry surfaces contaminated with secretions of nose, mouth, and eyes of an infected person has been proven about SARS-CoV-2 transmission. As disease progressed, a series of complications tends to develop, especially in critically ill and immunocompromised patients. Pathological studies showed representative features of acute respiratory distress syndrome (ARDS) and implications on multiple organs as well. However, no specific antiviral drugs or vaccines are immediately available for the treatment of this lethal disease. The efficacy of some promising antivirals needs to be investigated by ongoing clinical trials. In current circumstances, supportive care, precautions, and social distancing are the only preventive options to ameliorate COVID-19. To disinfect the environment, mainly chemical disinfectants are being used robustly. However, due to panic state, fright, and unawareness, people are using it violently, which can have an adverse effect on human health and environment. This review discusses about the potential harmful effect of disinfectants, if used inappropriately. Here, we will also discuss safe preventive options as an alternative to robust use of disinfection methods to fight against COVID-19.

Interactive role of salicylic acid and nitric oxide on transcriptional reprogramming for high temperature tolerance in lablab purpureus L.: Structural and functional insights using computational approaches.

Salicylic acid (SA) and nitric oxide (NO) are considered as putative plant growth regulators that are involved in the regulation of an array of plant's growth and developmental functions under environmental fluctuations when applied at lower concentrations. The possible involvement of NO in SA induced attenuation of high temperature (HT) induced oxidative stress in plants is however, still vague and need to be explored. Therefore, the present study aimed to investigates the biochemical and physiological changes induced by foliar spray of SA and NO combinations to ameliorate HT induced oxidative stress in Lablab purpureus L. Foliar application of combined SA and NO significantly improved relative water content (27.8 %), photosynthetic pigment content (67.2 %), membrane stability (45 %), proline content (1.0 %), expression of enzymatic antioxidants (7.1-18 %) along with pod yield (1.0 %). Heat Shock Factors (HSFs) play crucial roles in plants abiotic stress tolerance, however there structural and functional classifications in L. purpureus L. is still unknown. So, In-silico approach was also used for functional characterization and homology modelling of HSFs in L. purpureus. The experimental findings depicted that combine effect of SA and NO enhances tolerance in HT stressed L. purpureus L. plants by regulating physiological functions, antioxidants, expression and regulation of stress-responsive genes via transcriptional regulation of heat shock factor.

Response of Lablab purpureus L. to high temperature stress and role of exogenous protectants in mitigating high temperature induced oxidative damages.

Present study was conducted to explore the role of exogenous salicylic acid (SA), sodium nitroprusside (SNP), abscisic acid (ABA) and proline (PRO) in mitigating high-temperature (HT) induced oxidative stress in different Lablab purpureus L. cultivars. The attempt was made to examine whether these phytohormones, when applied exogenously, were able to regulate plant morpho-physiological behavior by modulating genes and proteins involved in antioxidant defense system. The HT stress induced membrane damage, degraded chlorophyll, generated redox metabolites and significantly reduced growth and biomass in all the cultivars. Among all the four treatments, foliar application of SA and SNP were most effective in the regulation of growth and physiological processes of the cultivars compared to ABA and PRO applications. Thus, signifying the protective role of SA and SNP in mitigation of HT induced oxidative stress and conferring HT stress tolerance in the cultivars. Gene expression and leaf proteome analysis revealed that these phytohormones were also involved in regulation of defense related gene expression, stress inducible proteins and de novo synthesis of specific proteins under HT stress. The experimental findings depict that foliar applications of SA and SNP enhances HT stress tolerance in lablab cultivars by modulating antioxidant defense system and by regulating bio-physical growth more effectively as compared to ABA and PRO application.

Salicylic acid and nitric oxide alleviate high temperature induced oxidative damage in Lablab purpureus L plants by regulating bio-physical processes and DNA methylation.

Salicylic acid (SA) and sodium nitroprusside (SNP, NO donor) modulates plant growth and development processes and recent findings have also revealed their involvement in the regulation of epigenetic factors under stress condition. In the present study, some of these factors were comparatively studied in hyacinth bean plants subjected to high temperature (HT) environment (40-42 °C) with and without exogenous application of SA and SNP under field condition. Exogenous application of SA and SNP substantially modulated the growth and biophysical process of hyacinth bean plants under HT environment. Exogenous application of SA and SNP also remarkably regulated the activities of antioxidant enzymes, modulated mRNA level of certain enzymes, improves plant water relation, enhance photosynthesis and thereby increasing plant defence under HT. Coupled restriction enzyme digestion-random amplification (CRED-RA) technique revealed that many methylation changes were "dose dependent" and HT significantly increased DNA damages as evidenced by both increase and decrease in bands profiles, methylation and de-methylation pattern. Thus, the result of the present study clearly shows that exogenous SA and SNP regulates DNA methylation pattern, modulates stress-responsive genes and can impart transient HT tolerance by synchronizing growth and physiological acclimatization of plants, thus narrowing the gaps between physio-biochemical and molecular events in addressing HT tolerance.

Chronic cerebral hypoperfusion-induced impairment of Aß clearance requires HB-EGF-dependent sequential activation of HIF1α and MMP9.

Chronic cerebral hypoperfusion (CCH) manifests Alzheimer's Disease (AD) neuropathology, marked by increased amyloid beta (Aß). Besides, hypoxia stimulates Heparin-binding EGF-like growth factor (HB-EGF) mRNA expression in the hippocampus. However, involvement of HB-EGF in CCH-induced Aß pathology remains unidentified. Here, using Bilateral Common Carotid Artery Occlusion mouse model, we explored the mechanism of HB-EGF regulated Aß induction in CCH. We found that HB-EGF inhibition suppressed, while exogenous-HB-EGF triggered hippocampal Aß, proving HB-EGF-dependent Aß increase. We also detected that HB-EGF affected the expression of primary Aß transporters, receptor for advanced glycation end-products (RAGE) and lipoprotein receptor-related protein-1 (LRP-1), indicating impaired Aß clearance across the blood-brain barrier (BBB). An HB-EGF-dependent loss in BBB integrity supported impaired Aß clearance. The effect of HB-EGF on Amyloid Precursor Protein pathway was relatively insignificant, suggesting a lesser effect on Aß generation. Delving into BBB disruption mechanism demonstrated HB-EGF-mediated stimulation of Matrix metalloprotease-9 (MMP9), which affected BBB via HB-EGF-ectodomain shedding and epidermal growth factor receptor activation. Examining the intersection of HB-EGF-regulated pathway and hypoxia revealed HB-EGF-dependent increase in transcription factor, Hypoxia-inducible factor-1alpha (HIF1α). Further, via binding to hypoxia-responsive elements in MMP9 gene, HIF1α stimulated MMP9 expression, and therefore appeared as a prominent intermediary in HB-EGF-induced BBB damage. Overall, our study reveals the essential role of HB-EGF in triggering CCH-mediated Aß accumulation. The proposed mechanism involves an HB-EGF-dependent HIF1α increase, generating MMP9 that stimulates soluble-HB-EGF/EGFR-induced BBB disintegration. Consequently, CCH-mediated hippocampal RAGE and LRP-1 deregulation together with BBB damage impair Aß transport and clearance where HB-EGF plays a pivotal role.

Molecular Approach Coupled with Biochemical Attributes to Elucidate the Presence of DYMV in Leaf Samples of Lablab purpureus. L Genotypes.

A laboratory study was delineated to ascertain the impact and the extent of Dolichos yellow mosaic virus (DYMV) on biochemical constituents and various enzyme levels in the leaves of hyacinth bean. DYMV-infected leaves of all the genotypes used in the study revealed significant and consistent changes in activities of CAT, APX, PPO, DHAR, and MDHAR paralleled with a compelling hike in proline levels. Unlike that in non-infected leaves of the genotypes VRSEM-301 and VRSEM-749, VRSEM-894 and VRSEM-855, the enzyme level did not alter much which extended equally with increased phenolics, suggesting a well-coordinated generation of free radicals thereby suppressing oxidative stress in the latter. The genotypes were also evaluated at molecular level for elucidating the presence of the virus by using five sets of primer pairs. Two primers viz., DAC1 and DAC2 witnessed the presence of the virus in both non-infected and infected leaves. The difference in the appearance and/or disappearance of bands according to non-infected to infect reverberates the variation between genotypes in defense against infection.

Exposure to As-, Cd-, and Pb-mixture induces Aß, amyloidogenic APP processing and cognitive impairments via oxidative stress-dependent neuroinflammation in young rats.

Environmental pollutants act as risk factors for Alzheimer's disease (AD), mainly affecting the aging population. We investigated early manifestations of AD-like pathology by a mixture of arsenic (As), cadmium (Cd), and lead (Pb), reported to impair neurodevelopment. We treated rats with As+Cd+Pb at their concentrations detected in groundwater of India, ie, 0.38, 0.098, and 0.22 ppm or 10 times of each, respectively, from gestation-05 to postnatal day-180. We identified dose-dependent increase in amyloid-beta (Aß) in frontal cortex and hippocampus as early as post-weaning. The effect was strongly significant during early-adulthood, reaching levels comparable to an Aß-infused AD-like rat model. The metals activated the proamyloidogenic pathway, mediated by increase in amyloid precursor protein (APP), and subsequent beta secretase (BACE) and presenilin (PS)-mediated APP-processing. Investigating the mechanism of Aß-induction revealed an augmentation in oxidative stress-dependent neuroinflammation that stimulated APP expression through interleukin-responsive-APP-mRNA 5'-untranslated region. We then examined the effects of individual metals and binary mixtures in comparison with the tertiary. Among individual metals, Pb triggered maximum induction of Aß, whereas individual As or Cd had a relatively non-significant effect on Aß despite enhanced APP, owing to reduced induction of BACE and PS. Interestingly, when combined the metals demonstrated synergism, with a major contribution by As. The synergistic effect was significant and consistent in tertiary mixture, resulting in the augmentation of Aß. Eventually, increase in Aß culminated in cognitive impairments in the young rats. Together, our data demonstrate that exposure to As+Cd+Pb induces premature manifestation of AD-like pathology that is synergistic, and oxidative stress and inflammation dependent.

Exposure to As, Cd and Pb-mixture impairs myelin and axon development in rat brain, optic nerve and retina.

Arsenic (As), lead (Pb) and cadmium (Cd) are the major metal contaminants of ground water in India. We have reported the toxic effect of their mixture (metal mixture, MM), at human relevant doses, on developing rat astrocytes. Astrocyte damage has been shown to be associated with myelin disintegration in CNS. We, therefore, hypothesized that the MM would perturb myelinating white matter in cerebral cortex, optic nerve (O.N.) and retina. We observed modulation in the levels of myelin and axon proteins, such as myelin basic protein (MBP), proteolipid protein, 2'-, 3'-cyclic-nucleotide-3'-phosphodiesterase, myelin-associated glycoprotein and neurofilament (NF) in the brain of developing rats. Dose and time-dependent synergistic toxic effect was noted. The MBP- and NF-immunolabeling, as well as luxol-fast blue (LFB) staining demonstrated a reduction in the area of intact myelin-fiber, and an increase in vacuolated axons, especially in the corpus-callosum. Transmission electron microscopy (TEM) of O.N. revealed a reduction in myelin thickness and axon-density. The immunolabeling with MBP, NF, and LFB staining in O.N. supported the TEM data. The hematoxylin and eosin staining of retina displayed a decrease in the thickness of nerve-fiber, plexiform-layer, and retinal ganglion cell (RGC) count. Investigating the mechanism revealed a loss in glutamine synthetase activity in the cerebral cortex and O.N., and a fall in the brain derived neurotrophic factor in retina. An enhanced apoptosis in MBP, NF and Brn3b-containing cells justified the diminution in myelinating axons in CNS. Our findings for the first time indicate white matter damage by MM, which may have significance in neurodevelopmental-pediatrics, neurotoxicology and retinal-cell biology.

Cypermethrin induces astrocyte apoptosis by the disruption of the autocrine/paracrine mode of epidermal growth factor receptor signaling.

Cypermethrin is reported to affect astrocytes in rat brain; however, its mechanism of action is obscure. Here, we observed an increase in apoptosis in the cortical astrocytes upon treatment of rats with cypermethrin. We then characterized the mechanism governing the apoptosis. Because the epidermal growth factor receptor (EGFR) signaling regulates the survival of astrocytes, we investigated the effect of cypermethrin on EGFR activation. The astrocytes exhibited an early and irreversible attenuation in the basal EGFR phosphorylation. Supportively, molecular docking studies revealed considerable homology in the docking mode of cypermethrin and the known EGFR inhibitors, erlotinib and AG1478, to the kinase domain of EGFR. Furthermore, treatment with cypermethrin demonstrated a downregulation in the intracellular and secreted levels of heparin-binding epidermal growth factor (HB-EGF), an EGFR ligand. AG1478 reduced the synthesis of HB-EGF, suggesting the dependence of HB-EGF on EGFR activation. In addition, a neutralizing antibody against HB-EGF diminished the basal EGFR levels, indicating ligand-dependent expression of EGFR. Likewise, cypermethrin caused irreversible suppression in the basal EGFR levels, which induced apoptosis in astrocytes. The apoptosis was prevented by exogenous HB-EGF. These data imply an autocrine/paracrine mode of action of HB-EGF-EGFR in astrocyte survival. Consequently, cypermethrin induced a mitochondria-mediated apoptosis, characterized by rise in Bax/Bcl-2 ratio and cleavage of caspase-9, -3, and -7, and the effect was prevented by HB-EGF. HB-EGF activated the extracellular signal-regulated kinases and AKT pathways that protected against apoptosis. Together, these data demonstrate that cypermethrin induces astrocyte apoptosis by disrupting the autocrine/paracrine mode of HB-EGF-EGFR signaling at two levels, irreversible loss of basal EGFR and downregulation of HB-EGF.