• Subhash C Lakhotia

      Articles written in Journal of Biosciences

    • Suppression of induced but not developmental apoptosis in Drosophila by Ayurvedic Amalaki Rasayana and Rasa-Sindoor

      Vibha Dwivedi Shweta Tiwary Subhash C Lakhotia

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      Earlier we showed formulation-specific beneficial effects of dietary supplement of Ayurvedic Amalaki Rasayana (AR, a herbal formulation) and Rasa-Sindoor (RS, a mercury-based organo-metallic formulation) on various biological parameters in Drosophila, parallel to traditional Ayurvedic literature. These formulations also suppressed cell death and pathology in fly models of neurodegeneration. To understand basis of inhibition of apoptosis, we examined effects of AR and RS on induced and developmental apoptosis in Drosophila. Dietary AR or RS significantly reduced apoptosis induced by GMR-GAL4-, sev-GAL4- or hs-GAL4-directed expression of Rpr, Hid or Grim (RHG) pro-apoptotic proteins or by GMR-GAL4-directed DIAP1-RNAi, resulting in significant restoration of organism's viability and eye morphology. AR or RS supplement enhanced levels of inhibitor of apoptosis proteins, DIAP1 and DIAP2, and of Bancal/Hrb57A, while the levels of RHG proteins and of initiator Dronc and effecter Drice caspases were reduced in non-apoptotic wild type as well as in RHG over-expressing tissues. Levels of Dronc or Drice remained unaffected in cells developmentally destined to die so that developmental apoptosis occurred normally. Elevated levels of DIAPs and reduced levels of RHG proteins and caspases reflect a more robust physiological state of AR or RS fed organisms allowing them to tolerate greater insults without triggering the cell-death response. Such homeo-static effects of these Rasayanas seem to contribute to ‘healthy ageing’, one of their effects suggested in traditional Ayurvedic practices.

    • Ayurvedic Amalaki Rasayana promotes improved stress tolerance and thus has anti-aging effects in Drosophila melanogaster


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      Amalaki Rasayana (AR) is a common Ayurvedic herbal formulation of Phyllanthus emblica fruits and some otheringredients, and is used for general good health and healthy aging. We reported it to improve life history traits and tosuppress neurodegeneration as well as induced apoptosis in Drosophila. The present study examines responses ofDrosophila reared on AR-supplemented food to crowding, thermal or oxidative stresses. Wild-type larvae/flies rearedon AR-supplemented food survived the various cell stresses much better than those reared on control food. AR-fedmutant park13 or DJ-1βDelta93 (Parkinson’s disease model) larvae/flies, however, showed only partial or no protection,respectively, against paraquat-induced oxidative stress, indicating essentiality of DJ-1β for AR-mediated oxidativestress tolerance. AR feeding reduced the accumulation of reactive oxygen species (ROS) and lipid peroxidation evenin aged (35-day-old) wild-type flies while enhancing superoxide dismutase (SOD) activity. We show that while Hsp70or Hsp83 expression under normal or stress conditions was not affected by AR feeding, Hsp27 levels were elevated inAR-fed wild-type control as well as heat-shocked larvae. Therefore, besides the known anti-oxidant activity ofPhyllanthus emblica fruits, dietary AR also enhances cellular levels of Hsp27. Our in vivo study on a model organismshows that AR feeding significantly improves tolerance to a variety of cell stresses through reduced ROS and lipidperoxidation on the one hand, and enhanced SOD activity and Hsp27 on the other. The resulting better homeostasisimproves life span and quality of organism’s life.

    • Amalaki Rasayana improved memory and neuronal metabolic activity in AβPP-PS1 mouse model of Alzheimer’s disease


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      Alzheimer’s disease (AD) is the most common neurodegenerative disorder characterized by progressive loss of memoryand cognitive function. The cerebral metabolic rate of glucose oxidation has been shown to be reduced in AD. The presentstudy evaluated efficacy of dietary Amalaki Rasayana (AR), an Ayurvedic formulation used in Indian traditional system, inAβPP-PS1 mouse model of AD in ameliorating memory and neurometabolism, and compared with donepezil, a standardFDA approved drug for AD. The memory of mice was measured using Morris Water Maze analysis. The cerebralmetabolism was followed by 13C labelling of brain amino acids in tissue extracts ex vivo using ${}^{1}$H-[${}^{13}$C]-NMR spectroscopytogether with a short time infusion of [1,6-${}^{13}$C2]glucose to mice. The intervention with Amalaki Rasayana showedimproved learning and memory in AbPP-PS1 mice. The ${}^{13}$C labelings of GluC4, GABAC2 and GlnC4 were reduced inAbPP-PS1 mice when compared with wild-type controls. Intervention of AR increased the ${}^{13}$C labelling of amino acidssuggesting a significant enhancement in glutamatergic and GABAergic metabolic activity in AβPP-PS1 mice similar to thatobserved with donepezil treatment. These data suggest that AR has potential to improve memory and cognitive function inAD.

    • Over-expression of Hsp83 in grossly depleted hsrω lncRNA background causes synthetic lethality and l(2)gl phenocopy in Drosophila


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      We examined interactions between the 83 kDa heat-shock protein (Hsp83) and hsrω long noncoding RNAs (lncRNAs) in hsrω66 Hsp90GFP homozygotes, which almost completely lack hsrω lncRNAs but over-express Hsp83. All +/+; hsrω66 Hsp90GFP progeny died before the third instar. Rare Sp/CyO; hsrω66 Hsp90GFP reached the third instar stage but phenocopied l(2)gl mutants, becoming progressively bulbous and transparent with enlarged brain and died after prolonged larval life. Additionally, ventral ganglia too were elongated. However, hsrω66 Hsp90GFP/TM6B heterozygotes, carrying +/ + or Sp/CyO second chromosomes, developed normally. Total RNA sequencing (+/+, +/+; hsrω66/hsrω66, Sp/CyO; hsrω66/ hsrω66, +/+; Hsp90GFP/Hsp90GFP and Sp/CyO; hsrω66 Hsp90GFP/hsrω66 Hsp90GFP late third instar larvae) revealed similar effects on many genes in hsrω66 and Hsp90GFP homozygotes. Besides additive effect on many of them, numerous additional genes were affected in Sp/CyO; hsrω66 Hsp90GFP larvae, with l(2)gl and several genes regulating the central nervous system being highly down-regulated in surviving Sp/CyO; hsrω66 Hsp90GFP larvae, but not in hsrω66 or Hsp90GFP single mutants. Hsp83 and several omega speckle-associated hnRNPs were bioinformatically found to potentially bind with these gene promoters and transcripts. Since Hsp83 and hnRNPs are also known to interact, elevated Hsp83 in an altered background of hnRNP distribution and dynamics, due to near absence of hsrω lncRNAs and omega speckles, can severely perturb regulatory circuits with unexpected consequences, including down-regulation of tumoursuppressor genes such as l(2)gl.

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