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Biology subjects

Mishra, P.

Publications and source records attributed to Mishra, P..

At least 55 records · Page 3Linked to original sources

The evolution of sexual dimorphism in gene expression in response to a manipulation of mate competition

Many genes are differentially expressed between males and females and patterns of sex-biased gene expression (SBGE) vary among species. Some of this variation is thought to have evolved in response to differences in mate competition among species that causes varying patterns of sex-specific selection. We used experimental evolution to test this by quantifying SBGE and sex-specific splicing in 15 Drosophila melanogaster populations that evolved for 104 generations in mating treatments that removed mate competition via enforced monogamy, or allowed mate competition in either small, simple or larger, structurally more complex mating environments. Consistent with sex-specific selection affecting SBGE, initially sex-biased genes diverged in expression more among treatments than unbiased genes, and there was greater expression divergence for male-than female-biased genes. It has been suggested the transcriptome should be feminized under monogamy because of the removal of sexual selection on males; we did not observe this, likely because selection differs in additional ways between monogamy vs. polygamy. Significant divergence in average expression dimorphism between treatments was observed and, in some treatment comparisons, the direction of the divergence differed across different sex-bias categories. There was not a generalized reduction in expression dimorphism under enforced monogamy.

evolutionary biology↗

Mitochondrial metabolism in primary and metastatic human kidney cancers

Most kidney cancers display evidence of metabolic dysfunction1-4 but how this relates to cancer progression in humans is unknown. We used a multidisciplinary approach to infuse 13C-labeled nutrients during surgical tumour resection in over 70 patients with kidney cancer. Labeling from [U-13C]glucose varies across cancer subtypes, indicating that the kidney environment alone cannot account for all metabolic reprogramming in these tumours. Compared to the adjacent kidney, clear cell renal cell carcinomas (ccRCC) display suppressed labelling of tricarboxylic acid (TCA) cycle intermediates in vivo and in organotypic slices cultured ex vivo, indicating that suppressed labeling is tissue intrinsic. Infusions of [1,2-13C]acetate and [U-13C]glutamine in patients, coupled with respiratory flux of mitochondria isolated from kidney and tumour tissue, reveal primary defects in mitochondrial function in human ccRCC. However, ccRCC metastases unexpectedly have enhanced labeling of TCA cycle intermediates compared to primary ccRCCs, indicating a divergent metabolic program during ccRCC metastasis in patients. In mice, stimulating respiration in ccRCC cells is sufficient to promote metastatic colonization. Altogether, these findings indicate that metabolic properties evolve during human kidney cancer progression, and suggest that mitochondrial respiration may be limiting for ccRCC metastasis but not for ccRCC growth at the site of origin.

cancer biology↗

Fusion of dysfunction muscle stem cells with myofibers induces sarcopenia in mice.

Sarcopenia, or age-associated muscle atrophy, is a progressive condition which affects [~]10-30% of the human geriatric population (1, 2). A number of contributors to sarcopenia have been proposed, including the progressive loss of muscle stem cells (MuSCs) with age. However, studies in mice have provided evidence that MuSC depletion is not sufficient to induce sarcopenia (3, 4). We recently showed that in response to age-associated mitochondrial damage, MuSCs self-remove by fusing with neighboring myofibers, which depletes the stem cell population of damaged progenitors (5). Here, we show that MuSC-myofiber fusion is sufficient to initiate myofiber atrophy in mice, which limits their motor function and lifespan. Conversely, inhibition of MuSC-myofiber fusion blocks myofiber atrophy with age, with a concomitant increase in the maximum lifespan of animals. These findings suggest a model where the accumulation fusion of damaged MuSCs with adult myofibers is a key driving feature of sarcopenia, and resolves the findings that MuSC depletion on its own does not initiate myofiber atrophy.

physiology↗

LRBA balances antigen presentation and T-cell responses by facilitating autophagy through the binding to PIK3R4 and FYCO1

Reduced autophagy is associated with the aberrant humoral response observed in lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency; however, the exact molecular mechanism and its impact on T-cell responses remain unknown. We identified two novel LRBA interactors, phosphoinositide 3-kinase regulatory subunit 4 (PIK3R4) and FYVE And Coiled-Coil Domain Autophagy Adaptor 1 (FYCO1). Both proteins play essential roles in different stages of autophagy. PIK3R4 facilitates the production of phosphatidylinositol-3 phosphate (PI(3)P) required for autophagosome formation and autophagosome-lysosome fusion, whereas FYCO1 allows autophagosome movement. LRBA-KO cells showed an impaired PI(3)P production, a delayed autophagosome-lysosome fusion, an accumulation of enlarged autophagosomes, and an atypical lysosomal positioning. These abnormalities led to decreased cargo material degradation and prolonged antigen presentation to T-cells via autophagy, resulting in increased production of proinflammatory cytokines, as autophagy is a major intracellular degradation system for major histocompatibility class II complex (MHCII) loading. Aberrant autophagosome formation, cargo degradation and antigen presentation were rescued by ectopic expression of WT-LRBA. In summary, we identified a novel function of LRBA that is crucial for T-cell-driven response through the interaction with two proteins of the autophagy machinery. These observations may contribute to the exacerbated T-cell dysregulation observed in LRBA-deficient patients.

immunology↗

A helminth mimic of TGF-β, TGM, enhances regenerative cutaneous wound healing and modulates immune cell recruitment and activation

Intestinal helminth parasites express excretory/secretory (ES) molecules, which modulate the type-2 immune response including anti-inflammatory and tissue repair pathways. TGF-{beta} mimic (TGM), an ES molecule secreted by Heligmosomoides polygyrus (Hp), binds TGF-{beta} receptors yet lacks structural homology to TGF-{beta} and exhibits distinct receptor interactions. We demonstrate TGM treatment enhanced wound healing and tissue regeneration in an in vivo wound biopsy model. TGM, in a 1.5% carboxymethylcellulose solution, was topically administered beneath a Tegaderm layer. Through histological analysis, increased restoration of normal tissue structure in the wound beds of TGM-treated mice was observed during mid- to late-stage wound healing. These observations included accelerated re-epithelialization and hair follicle regeneration, without increased scarring. Flow cytometric and gene expression analysis showed differential expansion of myeloid populations at different stages of wound healing. This included enhanced early accumulation and persistence of macrophages in TGM-treated wounds during the initial inflammatory phase. Additionally, the percentage of alternatively activated (M2) macrophages expressing CD206 was reduced with TGM treatment during early and mid-stage wound healing. scRNAseq analysis of TGM-treated wounds indicate upregulation of multiple wound healing-associated genes without expression of CD206 within macrophage subsets. Experiments with truncated TGM constructs revealed that the TGF{beta}-R binding domain was essential in enhancing the wound healing response. In summary, TGM can accelerate skin wound healing and pro-restorative maturation through its interaction with the TGF-{beta} receptor and stimulate the recruitment and reprogramming of specific macrophage subsets. This study indicates a role for TGM as a potential novel therapeutic option for enhanced wound healing. One-Sentence SummaryA helminth-derived protein leads to rapid wound closure, skin regeneration, and reprogramming of macrophage activation through TGF-{beta}R binding.

immunology↗

Cis-regulatory variation in relation to sex and sexual dimorphism in Drosophila melanogaster

Much of sexual dimorphism is likely due to sex-biased gene expression, which results from differential regulation of a genome that is largely shared between males and females. Here we use allele-specific expression to explore cis-regulatory variation in Drosophila melanogaster in relation to sex. We develop a Bayesian framework to infer the transcriptome-wide joint distribution of cis-regulatory effects across the sexes. We use this approach to quantify transcriptome-wide sex differences in cis-regulatory effects as well as examine patterns of cis-regulatory variation with respect to two other levels of variation in sexual dimorphism: (i) across genes varying in their degree of sex-biased expression, and (ii) among tissues that vary in their degree of dimorphism (e.g., relatively low dimorphism in heads vs high dimorphism in gonads). We uncover evidence of widespread cis-regulatory variation in all tissues examined, with female-biased genes being especially enriched for this variation. A sizeable proportion of cis-regulatory variation is inferred to have sex-specific effects, with sex-dependent cis effects being much more frequent in gonads than in heads. Finally, we detect some genes with reversed allelic imbalance between the sexes. Such variants could provide a mechanism for sex-specific dominance reversals, a phenomenon important for sexually antagonistic balancing selection.

evolutionary biology↗

Mitochondrial-encoded complex I impairment induces a targetable dependency on aerobic fermentation in H&uumlrthle cell carcinoma of the thyroid

A metabolic hallmark of cancer identified by Warburg is the increased consumption of glucose and secretion of lactate, even in the presence of oxygen. Although many tumors exhibit increased glycolytic activity, most forms of cancer rely on mitochondrial respiration for tumor growth. We report here that Hurthle cell carcinoma of the thyroid (HTC) models harboring mitochondrial DNA-encoded defects in complex I of the mitochondrial electron transport chain exhibit impaired respiration and alterations in glucose metabolism. CRISPR/Cas9 pooled screening identified glycolytic enzymes as selectively essential in complex I-mutant HTC cells. We demonstrate in cultured cells and a PDX model that small molecule inhibitors of lactate dehydrogenase selectively induce an ATP crisis and cell death in HTC. This work demonstrates that complex I loss exposes fermentation as a therapeutic target in HTC and has implications for other tumors bearing mutations that irreversibly damage mitochondrial respiration.

cancer biology↗

Complete mutational mapping of a GTPase switch in vivo reveals novel allosteric regulation

Allosteric regulation is central to protein function in cellular networks1. However, despite technological advances2,3 most studies of allosteric effects on function are conducted in heterologous environments2,4,5, limiting the discovery of allosteric mechanisms that rely on endogenous binding partners or posttranslational modifications to modulate activity. Here we report an approach that enables probing of new sites of allosteric regulation at residue-level resolution in essential eukaryotic proteins in their native biological context by comprehensive mutational scanning. We apply our approach to the central GTPase Gsp1/Ran. GTPases are highly regulated molecular switches that control signaling, with switching occurring via catalyzed GTP hydrolysis and nucleotide exchange. We find that 28% of 4,315 assayed mutations in Gsp1/Ran are highly deleterious, showing a toxic response identified by our assay as gain-of-function (GOF). Remarkably, a third of all positions enriched for GOF mutations (20/60) are outside the GTPase active site. Kinetic analysis shows that these distal sites are allosterically coupled to the active site, including a novel cluster of sites that alter the nucleotide preference of Gsp1 from GDP to GTP. We describe multiple distinct mechanisms by which allosteric mutations alter Gsp1/Ran cellular function by modulating GTPase switching. Our systematic discovery of new regulatory sites provides a functional map relevant to other GTPases such as Ras that could be exploited for targeting and reprogramming critical biological processes.

biophysics↗

Methylation pattern of nc886 in non-human mammals

BackgroundIn humans, the nc886 locus is a polymorphically imprinted metastable epiallele. Periconceptional conditions have an effect on the methylation status of nc886, and further, this methylation status is associated with health outcomes in later life, in line with the Developmental Origins of Health and Disease (DOHaD) hypothesis. Animal models would offer opportunities to study the associations between periconceptional conditions, nc886 methylation status and metabolic phenotypes further. Thus, we set out to investigate the methylation pattern of the nc886 locus in non-human mammals. DataWe obtained DNA methylation data from the data repository GEO for mammals, whose nc886 gene included all three major parts of nc886 and had sequency similarity of over 80% with the human nc886. Our final sample set consisted of DNA methylation data from humans, chimpanzees, bonobos, gorillas, orangutangs, baboons, macaques, vervets, marmosets and guinea pigs. ResultsIn human data sets the methylation pattern of nc886 locus followed the expected bimodal distribution, indicative of polymorphic imprinting. In great apes, we identified a unimodal DNA methylation pattern with 50% methylation level in all individuals and in all subspecies. In Old World monkeys, the between individual variation was greater and methylation on average was close to 60%. In guinea pigs the region around the nc886 homologue was non-methylated. Results obtained from the sequence comparison of the CTCF binding sites flanking the nc886 gene support the results on the DNA methylation data. ConclusionsOur results indicate that unlike in humans, nc886 is not a polymorphically imprinted metastable epiallele in non-human primates or in guinea pigs, thus implying that animal models are not applicable for nc886 research. The obtained data suggests that the nc886 region may be classically imprinted in great apes, and potentially also in Old World monkeys, but not in guinea pigs.

molecular biology↗

Bronco T (Shirisadi kasaya), a polyherbal formulation ameliorates LPS induced septicemia in rats

Septicemia is a life-threatening state, leading to multi-organ failure, ARDS and death. So, efforts are being made to identify novel therapies. Here, Bronco T (BT), a polyherbal formulation developed in 1984 for treating asthma, has been repurposed against septicemia induced ALI. The LPS (3mg/kg BW) was injected intraperitoneally before 24 hours, of surgery to assess the cardiorespiratory parameters, blood PaO2/FiO2, pulmonary water content and histological changes in the lungs. The pentoxifylline (PTX) (25 mg/kg b.w.) was used as the positive control. The PTX was given one hour before LPS and BT was given 3 hours (orally in different doses of 3, 1.5 and 0.75 gm/kg BW) to maintain the Cmax of the drug. The LPS treated group showed significant bradypnea, bradycardia and low heart rate frequency as observed, through elongated peaks (RR) and (MAP) respectively and finally death after 95 minutes of LPS injection. The PTX and BT (3gm/kg) pretreatment significantly prevented these changes (dose-dependent in the BT group). The survival was maintained up to 190 min after LPS. The Pentoxifylline showed a better response (75%) than Bronco T (72%). In both the treatments, a significant decrease in pulmonary water content and minimal neutrophil infiltration and intact alveoli-capillary membrane was seen in the transverse section (T.S) of the lungs. Conclusion: Significant improvement was noted in survival time, lesser tissue damage and better lung physiology by treating with Bronco T in LPS induced septicemia.

pharmacology and toxicology↗

Cyperus rotundus root extract inhibits progress of lymphedema in mouse tail model

Lymphedema is clinically manifested as swelling due to abnormal accumulation of interstitial fluid attributed to inefficient fluid uptake and reduced lymphatic flow. Here we have evaluated the effect of Cyperus rotundus root (CRR) ethanolic extract in a mouse tail model of lymphedema and hypothesized that Cyperus rotundus plant known for its anti-inflammatory effect through inhibition of TNF alpha will be effective in managing this condition. The skin was removed after leaving 1cm of distance from the base of the trunk. Cut was introduced in sterile condition. The animals were divided into Experimental control(EC) and Cyperus rotundus (CRR) treated groups. A change in tail volume around the wound was monitored upto the 20 days. Kinetics of the swelling was calculated for statistical significance. Further TS of upper part of the wound was stained with H&E stain and documented for histological changes RESULTSIn EC group, gradual rise in swelling was recorded, which peaked on 10th day and continued up to 15th day, followed by gradual decrease. In CR extract treated group, the swelling was significantly low and peak was obtained on 8th day, while in EC group the swelling was significantly higher and peak was obtained 11th day. The histological section show, fibrous band intersection the lobules of adipocyte and lymphatic vascular channel and muscles in the sub epithelium region in the EC group, which was very less in CRR group. CONCLUSIONSPolar fraction of CRR significantly prevents the progress of lymphedema and which lays an important role of this plant as for the drug development in future.

pharmacology and toxicology↗

Dominant role of adult neurogenesis-induced structural heterogeneities in driving plasticity heterogeneity in dentate gyrus granule cells

Neurons and synapses manifest pronounced variability in the amount of plasticity induced by identical activity patterns. The mechanisms underlying such plasticity heterogeneity, implicated in context-specific resource allocation during encoding, have remained unexplored. Here, we employed a systematic, unbiased, and physiologically constrained search to identify the mechanisms behind plasticity heterogeneity in dentate gyrus granule cells. We found that each of intrinsic, synaptic, and structural heterogeneities independently yielded heterogeneous plasticity profiles obtained with two different induction protocols. However, prior predictions about strong relationships between neuronal intrinsic excitability and plasticity emerged only when adult-neurogenesis-induced structural heterogeneities were accounted for. Strikingly, despite the concomitant expression of heterogeneities in structural, synaptic, and intrinsic neuronal properties, similar plasticity profiles were attainable through synergistic interactions among these heterogeneities. Importantly, consequent to strong relationships with intrinsic excitability measurements, we found that synaptic plasticity in the physiological range was achieved in immature cells despite their electrophysiologically-observed weak synaptic strengths. Together, our analyses unveil the dominance of neurogenesis-induced structural heterogeneities in driving plasticity heterogeneity in granule cells. Broadly, these analyses emphasize that the mechanistic origins of and the implications for plasticity heterogeneities need quantitative characterization across brain regions, particularly focusing on context-specific encoding of learned behavior.

neuroscience↗

Differential requirements for mitochondrial electron transport chain components in the adult murine liver

Mitochondrial electron transport chain (ETC) dysfunction due to mutations in the nuclear or mitochondrial genome is a common cause of metabolic disease in humans, and displays striking tissue specificity depending on the affected gene. The mechanisms underlying tissue specific phenotypes are not understood. Complex I (cI) is classically considered the entry point for electrons into the ETC, and in vitro experiments indicate that cI is required for basal respiration and maintenance of the NAD+/NADH ratio, an indicator of cellular redox status. This finding has largely not been tested in vivo. Here, we report that mitochondrial complex I (cI) is dispensable for homeostasis of the adult mouse liver; animals with hepatocyte-specific loss of cI function display no overt phenotypes or signs of liver damage, and maintain liver function, redox and oxygen status. Further analysis of cI-deficient livers did not reveal significant proteomic or metabolic changes, indicating little to no compensation is required in the setting of complex I loss. In contrast, complex IV (cIV) dysfunction in adult hepatocytes results in decreased liver function, impaired oxygen handling, steatosis, and liver damage, accompanied by significant metabolomic and proteomic perturbations. Metabolomic analysis suggests that the electron transfer flavoprotein complex constitutes a major route for electron entry into the hepatic ETC. Our results support a model whereby complex I loss is tolerated in the mouse liver because hepatocytes use alternative electron donors to fuel the mitochondrial ETC.

cell biology↗

microRNA775 targets a β-(1,3)-galactosyltransferase to regulate growth and development in Arabidopsis thaliana

MicroRNAs are critical regulators of gene expression in plants and other organisms, and are involved in regulating plethora of developmental processes. Evolutionarily, miRNAs can be ancient and conserved across species or recently evolved and young, which are not conserved across diverse plant groups. miR775 is a non-conserved miRNA identified only in Arabidopsis thaliana. Here, we investigated the functional significance of miR775 in A. thaliana and observed that miR775 targets a probable {beta}-(1,3)-galactosyltransferase gene at post transcriptional level. Phenotypic analysis of miR775 over-expression lines and the target mutant suggested miR775 regulates rosette size by elongating petiole length and increasing leaf area. Further, the expression of miR775 was found to be up-regulated in response to UV-B and hypoxia. Our results also suggest that miR775 regulated {beta}-(1,3)-galactosyltransferase may involve in regulating the {beta}-(1,3)-galactan content of arabinogalactans. Collectively, our findings establish a role of miR775 in regulating growth and development in A. thaliana. HighlightsO_LIThe role of an uncharacterized microRNA, miR775 has been explored C_LIO_LImiR775 targets a probable {beta}-(1,3)-galactosyltransferase involved in complex carbohydrate biosynthesis C_LIO_LImiR775 regulates rosette size in A. thaliana and may play role under UV light and hypoxia C_LI

plant biology↗

Abolished miR158 activity leads to 21-nucleotide tertiary phasiRNA biogenesis that targets NHX2 in Arabidopsis thaliana

Small RNAs including microRNAs (miRNAs) are short 20-24-nucleotide non-coding RNAs. They are key regulators of gene expression in plants and other organisms. Some small RNAs, mostly 22-nucleotide long trigger biogenesis of secondary small interfering RNAs (siRNAs). Those siRNAs having distinctive phased configuration are known as phased siRNAs (phasiRNAs) and act either in cis or trans enhancing silencing cascade. Here, we report natural variants of MIR158 having deletions or insertions led to negligible or reduced expression of miR158. The deletion/insertion events affected processing of primary transcript of miR158 to precursor and to mature miR158. We show that miR158 targets a pseudo-pentatricopeptide gene and its abolished activity led to 21-nucleotide tertiary phasiRNA generation from its target. The biogenesis of these phasiRNAS is triggered by TAS2 derived two siRNAs. Accordingly, small RNA analyses of these natural variants, mutants and over-expression lines of MIR158 or its target exhibited enhanced or reduced phasiRNA biogenesis. Finally, we functionally validated the highest expressed tertiary phasiRNA that targets NHX2 thereby regulating transpiration and stomatal conductance. Overall, we deciphered a new module of small RNA network, miRNA-TAS-siRNA-pseudogene-tertiary phasiRNA-NHX2, suggesting an additional layer of gene regulation and larger role of pseudogene in plants.

plant biology↗

A Wnt5a-Cdc42 axis controls aging and rejuvenation of hair-follicle stem cells

Normal hair growth occurs in cycles, comprising growth (anagen), cessation (catagen) and rest (telogen). Upon aging, the initiation of anagen is significantly delayed, which results in impaired hair regeneration. Hair regeneration is driven by hair follicle stem cells (HFSCs). We show here that aged HFSCs present with a decrease in canonical Wnt signaling and a shift towards non-canonical Wnt5a driven signaling which antagonizes canonical Wnt signaling. Elevated expression of Wnt5a in HFSCs upon aging results in elevated activity of the small RhoGTPase Cdc42 as well as a change in the spatial distribution of Cdc42 within HFSCs. Treatment of aged HFSC with a specific pharmacological inhibitor of Cdc42 activity termed CASIN to suppress the aging-associated elevated activity of Cdc42 restored canonical Wnt signaling in aged HFSCs. Treatment of aged mice in vivo with CASIN induced anagen onset and increased the percentage of anagen skin areas. Aging-associated functional deficits of HFSCs are at least in part intrinsic to HFSCs and can be restored by rational pharmacological approaches.

cell biology↗

Decision Support Systems based on Scientific Evidence: Bibliometric Networks of Invasive Lantana camara.

Extraction and analysis of useful knowledge from the vast amount of relevant published literature can add valuable insights to any research theme or area of interest. We introduce a simplified bibliometric data analysis protocol for gaining substantial insights into research thematics, which can also serve as a handy practical skill for researchers, while working from home. In this paper, we provide ways of developing a holistic research strategy using bibliometric-data driven approaches that integrate network analysis and information management, without the need of full paper access. This protocol is a comprehensive multi-modular pathway for analysis of metadata obtained from major scientific publishing houses by use of a Decision Support System (DSS). A simple case study on the invasive species Lantana camara has been presented as a proof-of-concept to show how one can implement this DSS based protocol. Some perspectives are also provided on how the outcomes can be used directly or scaled up for long term research interventions. We hope that this work will simplify exploratory literature review, and enable rational design of research objectives for scholars, as well as development of comprehensive grant proposals that address gaps in research.

scientific communication and education↗

Refinement of Genome assemblies of Pigeonpea (Cajanus cajan)

Genome assembly of short reads from large plant genomes remains a challenge in computational biology despite major developments in Next Generation sequencing. Of late multiple draft assemblies of plant genomes are reported in many organisms. The draft assemblies of Cajanus cajan are with different levels of genome completeness; contain large number of repeats, gaps and segmental duplications. Draft assemblies with portions of genome missing, are shorter than the referenced original genome. These assemblies come with low map accuracy affecting further functional annotation and prediction of gene component as desired by crop researchers. Genome coverage i.e. number of sequenced raw reads mapped on to certain locations of the genome is an important quality indicator of completeness and assembly quality in draft assemblies. Present work was aimed at improvement of coverage in reported de novo sequenced draft genomes (GCA_000340665.1 and GCA_000230855.2) of Pigeonpea, a legume widely cultivated in India. The two assemblies comprised 72% and 75% of estimated coverage of genome respectively. We employed assembly reconciliation approach to compare draft assemblies and merged them to generate a high quality near complete assembly with enhanced contiguity. Finished assembly has reduced number of gaps than reported in draft assemblies and improved genome coverage of 82.4%. Quality of the finished assembly was evaluated using various quality metrics and for presence of specific trait related functional genes. Employed pair-end and mate-pair local library data sets enabled to resolve gaps, repeats and other sequence errors yielding lengthier scaffolds compared to two draft assemblies. We report prediction of putative host resistance genes from improved sequence against Fusarium wilt disease and evaluated them in both wet laboratory and field phenotypic conditions.

genomics↗