Diet-induced obesity mouse models are widely utilized to investigate the underlying mechanisms of dyslipidemia, glucose intolerance, insulin resistance, hepatic steatosis, and type 2 diabetes mellitus (T2DM), as well as for screening potential drug compounds. However, there is limited knowledge regarding specific signature lipids that accurately reflect dietary disorders. In this study, we aimed to identify key lipid signatures using LC/MS-based untargeted lipidomics in the plasma, liver, adipose tissue (AT), and skeletal muscle tissues (SKM) of male C57BL/6J mice that were fed chow, LFD, or obesogenic diets (HFD, HFHF, and HFCD) for a duration of 20 weeks. Furthermore, we conducted a comprehensive lipid analysis to assess similarities and differences with human lipid profiles. The mice fed obesogenic diets exhibited weight gain, glucose intolerance, elevated BMI, glucose and insulin levels, and a fatty liver, resembling characteristics of T2DM and obesity in humans. In total, we identified approximately 368 lipids in plasma, 433 in the liver, 493 in AT, and 624 in SKM. Glycerolipids displayed distinct patterns across the tissues, differing from human findings. However, changes in sphingolipids, phospholipids, and the expression of inflammatory and fibrotic genes showed similarities to reported human findings. Significantly modulated pathways in the obesogenic diet-fed groups included ceramide de novo synthesis, sphingolipid remodeling, and the carboxylesterase pathway, while lipoprotein-mediated pathways were minimally affected. This study provides a tissue-specific comparison of lipid composition, highlighting the usefulness of DIO models in preclinical research. However, caution is warranted when extrapolating findings from these models to dyslipidemia-associated pathologies and their complications in humans.
Title: Benzimidazole-derived carbohydrazones as dual monoamine oxidases and acetylcholinesterase inhibitors: design, synthesis, and evaluation Kumar S, Jaiswal S, Gupta SK, Ayyannan SR Ref: J Biomol Struct Dyn, :1, 2023 : PubMed
A series of novel benzimidazole-derived carbohydrazones was designed, synthesized and evaluated for their dual inhibition potential against monoamine oxidases (MAOs) and acetylcholinesterase (AChE) using multitarget-directed ligand approach (MTDL). The investigated compounds have exhibited moderate to excellent in vitro MAOs/AChE inhibitory activity at micromolar to nanomolar concentrations. Compound 12, 2-(1H-Benzo[d]imidazol-1-yl)-N'-[1-(4-hydroxyphenyl) ethylidene]acetohydrazide has emerged as a lead dual MAO-AChE inhibitor by exhibiting superior multi-target activity profile against MAO-A (IC(50) = 0.067 +/- 0.018 microM), MAO-B (IC(50) = 0.029 +/- 0.005 microM) and AChE (IC(50) = 1.37 +/- 0.026 microM). SAR studies suggest that the site A (hydrophobic ring) and site C (semicarbazone linker) modifications attempted on the semicarbazone-based MTDL resulted in a significant enhancement in the MAO-A/B inhibitory potential and a drastic decrease in the AChE inhibitory activity. Further, molecular docking and dynamics simulation experiments disclosed the possible molecular interactions of inhibitors inside the active site of respective enzymes. Also, computational prediction of drug-likeness and ADME parameters of test compounds revealed their drug-like characteristics.Communicated by Ramaswamy H. Sarma.
Pearl millet is an important cereal crop of semi-arid regions since it is highly nutritious and climate resilient. However, pearl millet is underutilized commercially due to the rapid onset of hydrolytic rancidity of seed lipids post-milling. We investigated the underlying biochemical and molecular mechanisms of rancidity development in the flour from contrasting inbred lines under accelerated aging conditions. The breakdown of storage lipids (triacylglycerols; TAG) was accompanied by free fatty acid accumulation over the time course for all lines. The high rancidity lines had the highest amount of FFA by day 21, suggesting that TAG lipases may be the cause of rancidity. Additionally, the high rancidity lines manifested substantial amounts of volatile aldehyde compounds, which are characteristic products of lipid oxidation. Lipases with expression in seed post-milling were sequenced from low and high rancidity lines. Polymorphisms were identified in two TAG lipase genes (PgTAGLip1 and PgTAGLip2) from the low rancidity line. Expression in a yeast model system confirmed these mutants were non-functional. We provide a direct mechanism to alleviate rancidity in pearl millet flour by identifying mutations in key TAG lipase genes that are associated with low rancidity. These genetic variations can be exploited through molecular breeding or precision genome technologies to develop elite pearl millet cultivars with improved flour shelf life.
Title: Metal determination and biochemical status of marine fishes facilitate the biomonitoring of marine pollution Kumar N, Bhushan S, Gupta SK, Kumar P, Chandan NK, Singh DK Ref: Mar Pollut Bull, 170:112682, 2021 : PubMed
In the present study, the bioaccumulation of chromium, manganese, cobalt, copper, zinc, selenium, arsenic, strontium, cadmium, tin, antimony and lead in tissues of thirty marine fish species collected from New Ferry Whorf, Sassoon dock and Versova fishing harbour in Mumbai, India, were analysed. The bioaccumulation patterns of these twelve elements were determined to assess pollution biomarkers based on cellular and oxidative stresses. Catalase, superoxide dismutase and glutathione-s-transferase, glycolytic enzymes viz. lactate dehydrogenase and malate dehydrogenase, protein metabolism enzymes viz. aspartate transferase and alanine transferase, and lipid peroxidation were significantly higher in muscle and gill tissues. The activities of the neurotransmitter enzyme acetylcholine esterase in muscle and brain tissues was inhibited due to pollution. This study suggested that biochemical attributes such as oxidative stress enzymes, cellular biomarkers, neurotransmitter enzymes and metal and metalloid contamination could be successfully employed, even at low concentrations, as reliable biomarkers for biomonitoring of contaminated marine ecosystems.
Title: Neuroprotective effects of quercetin produced by an endophytic fungus Nigrospora oryzae isolated from Tinospora cordifolia Vig R, Bhadra F, Gupta SK, Krishnamurthy S, Vasundhara M Ref: J Appl Microbiol, :, 2021 : PubMed
AIMS: Alzheimer's disease is considered as one of the most prevalent neurodegenerative disorders and dementia is core symptom of this disease. Present study was aimed to test bioactive compounds produced by endophytic fungus on the inhibition of acetylcholinesterase (AChE) activity and identify the compound responsible for this activity. METHODS AND RESULTS: Endophytic fungi were isolated from the medicinal plant Tinospora cordifolia and screened for acetylcholinesterase (AChE) inhibitory and antioxidant activity. The extract of one of the isolates Nigrospora oryzae (GL15) showed maximum AChE inhibition as well as antioxidant activity. The compound responsible for AChE inhibition (fraction 3) was identified as quercetin based on UV, FTIR spectra, HPLC and ESI-MS analysis. Further, the identity of quercetin in the extract of fraction 3 was confirmed by (1) H NMR analysis. This extract showed anti-dementia-like activity in scopolamine (SCO) model. The minimal effective dose of the extract of fraction 3 modulated the scopolamine-provoked cognitive deficits like impairments in spatial recognition memory and latency period in Y-maze and passive avoidance test (PAT) respectively. The SCO-induced modulation in cholinergic pathway was ameliorated by the extract of N. oryzae in hippocampus, resulting in decrease in AChE activity and restoration of cytoarchitecture of hippocampus. CONCLUSIONS: The bioactive compound quercetin produced by N. oryzae may cure the learning and memory shortfalls via AChE mediated mechanism in experimental mice. SIGNIFICANCE AND IMPACT OF THE STUDY: The endophytic fungus N. oryzae serves as a potential source for the bioactive compound quercetin, which play an important role in the management of Alzheimer's disease.
Alzheimer's disease (AD) is a neurodegenerative disorder with multifactorial pathogenesis. Monoamine oxidase (MAO) and acetylcholinesterase enzymes (AChE) are potential targets for the treatment of AD. A total of 15 new propargyl containing 4,6-diphenylpyrimidine derivatives were synthesized and screened for the MAO and AChE inhibition activities along with ROS production inhibition and metal-chelation potential. All the synthesized compounds were found to be selective and potent inhibitors of MAO-A and AChE enzymes at nanomolar concentrations. VB1 was found to be the most potent MAO-A and BuChE inhibitor with IC50 values of 18.34 +/- 0.38 nM and 0.666 +/- 0.03 muM, respectively. It also showed potent AChE inhibition with an IC50 value of 30.46 +/- 0.23 nM. Compound VB8 was found to be the most potent AChE inhibitor with an IC50 value of 9.54 +/- 0.07 nM and displayed an IC50 value of 1010 +/- 70.42 nM against the MAO-A isoform. In the cytotoxic studies, these compounds were found to be nontoxic to the human neuroblastoma SH-SY5Y cells even at 25 muM concentration. All the compounds were found to be reversible inhibitors of MAO-A and AChE enzymes. In addition, these compounds also showed good neuroprotective properties against 6-OHDA- and H2O2-induced neurotoxicity in SH-SY5Y cells. All the compounds accommodate nicely to the hydrophobic cavity of MAO-A and AChE enzymes. In the molecular dynamics simulation studies, both VB1 and VB8 were found to be stable in the respective cavities for 30 ns. Thus, 4,6-diphenylpyrimidine derivatives can act as promising leads in the development of dual-acting inhibitors targeting MAO-A and AChE enzymes for the treatment of Alzheimer's disease.
The novel hybrids bearing 4-aminopyridine (4-AP) tethered with substituted 1,3,4-oxadiazole nucleus were designed, synthesized, and evaluated for their potential AChE inhibitory property along with significant antioxidant potential. The inhibitory potential (IC50) of synthesized analogs was evaluated against human cholinesterases (hAChE and hBChE) using Ellman's method. Among all the compounds, 9 with 4-hydroxyl substituent showed maximum hAChE inhibition with the non-competitive type of enzyme inhibition (IC50=1.098microM; Ki=0.960microM). Further, parallel artificial membrane permeation assay (PAMPA-BBB) showed significant BBB permeability in most of the synthesized compounds. Meanwhile, compound 9 also inhibited AChE-induced Abeta aggregation (38.2-65.9%) by thioflavin T assay. The in vivo behavioral studies showed dose-dependent improvement in learning and memory by compound 9. The ex vivo studies also affirmed the significant AChE inhibition and antioxidant potential of compound 9 in brain homogenates.
Aim: A breakthrough in modern medicine, in terms of treatment of Alzheimer's disease, is yet to be seen, as the scene is currently plagued with numerous clinical trial failures. Here, we are exploring multifunctional hybrid sulfonamides for their anti-Alzheimer activity due to the complex nature of the disease. Results & methodology: Compound 41 showed significant inhibition of MMP-2 (IC50: 18.24 +/- 1.62 nM), AChE (IC50: 4.28 +/- 0.15 muM) and BuChE (IC50: 1.32 +/- 0.02 muM). It also exhibited a metal-chelating property, as validated by an in vitro metal-induced Abeta aggregation assay using confocal fluorescence imaging. Whereas, MTT and DPPH assays revealed it to be nontoxic and neuroprotective with substantial antioxidant property. Conclusion: The present study puts forth potent yet nontoxic lead molecules, which foray into the field of multitargeted agents for the treatment of Alzheimer's disease.
Novel multifunctional 3,6-Diphenyl-1,4-bis(phenylsulfonyl)piperazine-2,5-dione derivatives were designed and synthesized for the treatment of Alzheimer's disease (AD). The designed scaffold has blood brain barrier penetrating ability, acetylcholinesterase (AChE) and matrix metalloproteinase-2 (MMP-2) inhibition potential. Compounds 52 and 46 showed very significant inhibition against AChE, IC50=32.45+/-0.044, 28.65+/-0.029, BuChE, IC50=157.95+/-0.264, 160.58+/-0.082 and MMP-2, IC50=36.83+/-0.015, 19.57+/-0.005 (nM). In the enzyme kinetics study, lead molecule 46 showed non-competitive inhibition of AChE with Ki=7nM and competitive inhibition of MMP-2 with Ki=20nM. Compounds 52 and 46 inhibited AChE-induced Abeta aggregation at 20muM. The compounds also exhibited in-vitro antioxidant potential in DPPH assay. Further, compound 46 was found to be a promising neuroprotective agent in MC65cells. Lead molecule 46 significantly enhanced working memory in scopolamine induced amnesia animal model at dose of 5mg/kg dose. The mitochondrial membrane potential was restored in animals when treated with compounds 52 and 46.
Title: Design, synthesis, and pharmacological evaluation of 2-amino-5-nitrothiazole derived semicarbazones as dual inhibitors of monoamine oxidase and cholinesterase: effect of the size of aryl binding site Tripathi RKP, V MS, Gupta SK, Krishnamurthy S, Ayyannan SR Ref: J Enzyme Inhib Med Chem, 33:37, 2018 : PubMed
A series of 2-amino-5-nitrothiazole derived semicarbazones were designed, synthesised and investigated for MAO and ChE inhibition properties. Most of the compounds showed preferential inhibition towards MAO-B. Compound 4, (1-(1-(4-Bromophenyl)ethylidene)-4-(5-nitrothiazol-2-yl)semicarbazide) emerged as lead candidate (IC50 = 0.212 microM, SI = 331.04) against MAO-B; whereas compounds 21 1-(5-Bromo-2-oxoindolin-3-ylidene)-4-(5-nitrothiazol-2-yl)semicarbazide (IC50 = 0.264 microM) and 17 1-((4-Chlorophenyl) (phenyl)methylene)-4-(5-nitrothiazol-2-yl)semicarbazide (IC50 = 0.024 microM) emerged as lead AChE and BuChE inhibitors respectively; with activity of compound 21 almost equivalent to tacrine. Kinetic studies indicated that compound 4 exhibited competitive and reversible MAO-B inhibition while compounds 21 and 17 showed mixed-type of AChE and BuChE inhibition respectively. Docking studies revealed that these compounds were well-accommodated within MAO-B and ChE active sites through stable hydrogen bonding and/or hydrophobic interactions. This study revealed the requirement of small heteroaryl ring at amino terminal of semicarbazone template for preferential inhibition and selectivity towards MAO-B. Our results suggest that 5-nitrothiazole derived semicarbazones could be further exploited for its multi-targeted role in development of anti-neurodegenerative agents. [Formula: see text] A library of 2-amino-5-nitrothiazole derived semicarbazones (4-21) was designed, synthesised and evaluated for in vitro MAO and ChE inhibitory activity. Compounds 4, 21 and 17 (shown) have emerged as lead MAO-B (IC50:0.212 microM, competitive and reversible), AChE (IC50:0.264 microM, mixed and reversible) and BuChE (IC50:0.024 microM, mixed and reversible) inhibitor respectively. SAR studies disclosed several structural aspects significant for potency and selectivity and indicated the role of size of aryl binding site in potency and selectivity towards MAO-B. Antioxidant activity and neurotoxicity screening results further suggested their multifunctional potential for the therapy of neurodegenerative diseases.
Neurogenesis, a process of generation of new neurons, is reported to be reduced in several neurodegenerative disorders including Alzheimer's disease (AD). Induction of neurogenesis by targeting endogenous neural stem cells (NSC) could be a promising therapeutic approach to such diseases by influencing the brain self-regenerative capacity. Curcumin, a neuroprotective agent, has poor brain bioavailability. Herein, we report that curcumin-encapsulated PLGA nanoparticles (Cur-PLGA-NPs) potently induce NSC proliferation and neuronal differentiation in vitro and in the hippocampus and subventricular zone of adult rats, as compared to uncoated bulk curcumin. Cur-PLGA-NPs induce neurogenesis by internalization into the hippocampal NSC. Cur-PLGA-NPs significantly increase expression of genes involved in cell proliferation (reelin, nestin, and Pax6) and neuronal differentiation (neurogenin, neuroD1, neuregulin, neuroligin, and Stat3). Curcumin nanoparticles increase neuronal differentiation by activating the Wnt/beta-catenin pathway, involved in regulation of neurogenesis. These nanoparticles caused enhanced nuclear translocation of beta-catenin, decreased GSK-3beta levels, and increased promoter activity of the TCF/LEF and cyclin-D1. Pharmacological and siRNA-mediated genetic inhibition of the Wnt pathway blocked neurogenesis-stimulating effects of curcumin. These nanoparticles reverse learning and memory impairments in an amyloid beta induced rat model of AD-like phenotypes, by inducing neurogenesis. In silico molecular docking studies suggest that curcumin interacts with Wif-1, Dkk, and GSK-3beta. These results suggest that curcumin nanoparticles induce adult neurogenesis through activation of the canonical Wnt/beta-catenin pathway and may offer a therapeutic approach to treating neurodegenerative diseases such as AD, by enhancing a brain self-repair mechanism.
Title: Novel nonsense mutation of ABHD5 in Dorfman-Chanarin syndrome with unusual findings: a challenge for genotype-phenotype correlation. Aggarwal S, Maras JS, Alam S, Khanna R, Gupta SK, Ahuja A Ref: Eur Journal of Medical Genetics, 55:173, 2012 : PubMed
Dorfman-Chanarin syndrome is a rare neutral lipid disorder characterised by icthyosis, hepatic steatosis and multisystemic involvement of varying magnitude. It is an autosomal recessive disease caused by mutations in the ABHD5 gene. We report a consanguineous family of Afgani origin, with four affected siblings who were found to have a novel homozygous nonsense mutation g. [27606 G > T]; [27606 G > T]. The clinical findings were unusual in the form of early cirrhosis and hepatic decompensation in one sibling, presence of corneal opacities in male siblings and tessellated fundus in all affected children. Steatosis was minimal in liver biopsy specimens and all children had low vitamin D levels. Genotype-phenotype correlations have not been possible in Dorfman-Chanarin syndrome and the present report raises further challenges for the same.
Title: Carbaryl-induced behavioural and reproductive abnormalities in the earthworm Metaphire posthuma: a sensitive model Gupta SK, Saxena PN Ref: Altern Lab Anim, 31:587, 2003 : PubMed
Carbaryl, an N-methyl carbamate insecticide, is used in India to control foliar insects, but, due to soil contamination, it also adversely affects non-target organisms such as earthworms. This paper deals with the toxic effects of carbaryl on the behavioural and reproductive profiles of the earthworm, Metaphire posthuma. Locomotion and geotaxis were significantly affected, even after a 20-minute exposure to 0.125ppm carbaryl. The hatching of cocoons was altered at 0.5ppm, whereas cocoon production was retarded even at 0.125ppm carbaryl. No cocoon production was observed at 2.0ppm carbaryl. Sperm head abnormalities were reported even at the lowest test concentration of 0.125ppm. Wavy head abnormalities were observed at 0.125ppm carbaryl, whereas at 0.25ppm and 0.5ppm, the sperm heads became amorphous and the head nucleus was turned into granules deposited within the wavy head. It is concluded that the earthworm could be used as an ecosystem model for the initial toxicity testing of environmental pollutants.
