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On page 1 showing 1 ~ 14 papers out of 14 papers

The piRNA pathway is developmentally regulated during spermatogenesis in Drosophila.

  • Emilie Quénerch'du‎ et al.
  • RNA (New York, N.Y.)‎
  • 2016‎

PIWI-interacting RNAs (piRNAs) are predominantly produced in animal gonads to suppress transposons during germline development. Our understanding about the piRNA biogenesis and function is predominantly from studies of the Drosophila female germline. piRNA pathway function in the male germline, however, remains poorly understood. To study overall and stage-specific features of piRNAs during spermatogenesis, we analyzed small RNAs extracted from entire wild-type testes and stage-specific arrest mutant testes enriched with spermatogonia or primary spermatocytes. We show that most active piRNA clusters in the female germline do not majorly contribute to piRNAs in testes, and abundance patterns of piRNAs mapping to different transposon families also differ between male and female germlines. piRNA production is regulated in a stage-specific manner during spermatogenesis. The piRNAs in spermatogonia-enriched testes are predominantly transposon-mapping piRNAs, and almost half of those exhibit a ping-pong signature. In contrast, the primary spermatocyte-enriched testes have a dramatically high amount of piRNAs targeting repeats like suppressor of stellate and AT-chX The transposon-mapping piRNAs in the primary spermatocyte stages lacking Argonaute3 expression also show a ping-pong signature, albeit to a lesser extent. Consistently, argonaute3 mutant testes also retain ping-pong signature-bearing piRNAs, suggesting that a noncanonical ping-pong cycle might act during spermatogenesis. Our study shows stage-specific regulation of piRNA biogenesis during spermatogenesis: An active ping-pong cycle produces abundant transposon-mapping piRNAs in spermatogonia, while in primary spermatocytes, piRNAs act to suppress the repeats and transposons.


The Global ECT-MRI Research Collaboration (GEMRIC): Establishing a multi-site investigation of the neural mechanisms underlying response to electroconvulsive therapy.

  • Leif Oltedal‎ et al.
  • NeuroImage. Clinical‎
  • 2017‎

Major depression, currently the world's primary cause of disability, leads to profound personal suffering and increased risk of suicide. Unfortunately, the success of antidepressant treatment varies amongst individuals and can take weeks to months in those who respond. Electroconvulsive therapy (ECT), generally prescribed for the most severely depressed and when standard treatments fail, produces a more rapid response and remains the most effective intervention for severe depression. Exploring the neurobiological effects of ECT is thus an ideal approach to better understand the mechanisms of successful therapeutic response. Though several recent neuroimaging studies show structural and functional changes associated with ECT, not all brain changes associate with clinical outcome. Larger studies that can address individual differences in clinical and treatment parameters may better target biological factors relating to or predictive of ECT-related therapeutic response. We have thus formed the Global ECT-MRI Research Collaboration (GEMRIC) that aims to combine longitudinal neuroimaging as well as clinical, behavioral and other physiological data across multiple independent sites. Here, we summarize the ECT sample characteristics from currently participating sites, and the common data-repository and standardized image analysis pipeline developed for this initiative. This includes data harmonization across sites and MRI platforms, and a method for obtaining unbiased estimates of structural change based on longitudinal measurements with serial MRI scans. The optimized analysis pipeline, together with the large and heterogeneous combined GEMRIC dataset, will provide new opportunities to elucidate the mechanisms of ECT response and the factors mediating and predictive of clinical outcomes, which may ultimately lead to more effective personalized treatment approaches.


1H-1,2,3-Triazole Tethered Nitroimidazole-Isatin Conjugates: Synthesis, Docking, and Anti-Proliferative Evaluation against Breast Cancer.

  • Sumit Kumar‎ et al.
  • ACS omega‎
  • 2018‎

1H-1,2,3-Triazole tethered imidazole-isatin and imidazole-isatin-thiosemicarbazone conjugates were synthesized and evaluated against MCF-7 and MDA-MB-231 cell lines. Antiproliferative activities of the synthesized conjugates revealed an optimum combination of longer alkyl chain length as spacer and a halogen-substituent on the isatin ring as a pre-requisite for good activity. The compound 6g with an optimum combination of chloro-substituent at C-5 position of isatin ring and a butyl chain length proved to be most active and noncytotoxic with IC50s of 54.25 and 26.12 μM against MCF-7 and MDA-MB-231 cell lines, respectively.


Analysis of Hydra PIWI proteins and piRNAs uncover early evolutionary origins of the piRNA pathway.

  • Robyn S M Lim‎ et al.
  • Developmental biology‎
  • 2014‎

To preserve genome integrity, an evolutionarily conserved small RNA-based silencing mechanism involving PIWI proteins and PIWI-interacting RNAs (piRNAs) represses potentially deleterious transposons in animals. Although there has been extensive research into PIWI proteins in bilaterians, these proteins remain to be examined in ancient phyla. Here, we investigated the PIWI proteins Hywi and Hyli in the cnidarian Hydra, and found that both PIWI proteins are enriched in multipotent stem cells, germline stem cells, and in the female germline. Hywi and Hyli localize to the nuage, a perinuclear organelle that has been implicated in piRNA-mediated transposon silencing, together with other conserved nuage and piRNA pathway components. Our findings provide the first report of nuage protein localization patterns in a non-bilaterian. Hydra PIWI proteins possess symmetrical dimethylarginines: modified residues that are known to aid in PIWI protein localization to the nuage and proper piRNA loading. piRNA profiling suggests that transposons are the major targets of the piRNA pathway in Hydra. Our data suggest that piRNA biogenesis through the ping-pong amplification cycle occurs in Hydra and that Hywi and Hyli are likely to preferentially bind primary and secondary piRNAs, respectively. Presumptive piRNA clusters are unidirectionally transcribed and primarily give rise to piRNAs that are antisense to transposons. These results indicate that various conserved features of PIWI proteins, the piRNA pathway, and their associations with the nuage were likely established before the evolution of bilaterians.


The Tudor domain protein Tapas, a homolog of the vertebrate Tdrd7, functions in the piRNA pathway to regulate retrotransposons in germline of Drosophila melanogaster.

  • Veena S Patil‎ et al.
  • BMC biology‎
  • 2014‎

Piwi-interacting RNAs (piRNAs) are a special class of small RNAs that provide defense against transposable elements in animal germline cells. In Drosophila, germline piRNAs are thought to be processed at a unique perinuclear structure, the nuage, that houses piRNA pathway proteins including the Piwi clade of Argonaute family proteins, along with several Tudor domain proteins, RNA helicases and nucleases. We previously demonstrated that Tudor domain protein Tejas (Tej), an ortholog of vertebrate Tdrd5, is an important component of the piRNA pathway.


Brain Changes Induced by Electroconvulsive Therapy Are Broadly Distributed.

  • Olga Therese Ousdal‎ et al.
  • Biological psychiatry‎
  • 2020‎

Electroconvulsive therapy (ECT) is associated with volumetric enlargements of corticolimbic brain regions. However, the pattern of whole-brain structural alterations following ECT remains unresolved. Here, we examined the longitudinal effects of ECT on global and local variations in gray matter, white matter, and ventricle volumes in patients with major depressive disorder as well as predictors of ECT-related clinical response.


Theoretical and Anti-Klebsiella pneumoniae Evaluations of Substituted 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxamide and Imidazopyridine Hydrazide Derivatives.

  • Suraj N Mali‎ et al.
  • Molecules (Basel, Switzerland)‎
  • 2023‎

A series of multistep synthesis protocols was adopted to synthesize substituted imidazopyridines (IMPs) (SM-IMP-01 to SM-IMP-13, and DA-01-05). All substituted IMPs were then characterized using standard spectroscopic techniques such as 1H-NMR, 13C-NMR, elemental analyses, and mass spectrometry. Our both in vitro qualitative and quantitative results for antibacterial analysis, against Klebsiella pneumoniae ATCC 4352 and Bacillus subtilis ATCC 6051 suggested that all compounds essentially exhibited activity against selected strains of bacteria. Our DFT analyses suggested that the compounds of the SM-IMP-01-SM-IMP-13 series have HOMO/LUMO gaps within 4.43-4.69 eV, whereas the compounds of the DA-01-DA-05 series have smaller values of the HOMO/LUMO gaps, 3.24-4.17 eV. The lowest value of the global hardness and the highest value of the global softness, 2.215 and 0.226 eV, respectively, characterize the compound SM-IMP-02; thus, it is the most reactive compound in the imidazopyridine carboxamide series (except hydrazide series). This compound also depicted lesser MIC values against Klebsiella pneumoniae ATCC 4352 and Bacillus subtilis ATCC 6051 as 4.8 µg/mL, each. In terms of another series, hydrazide DA-05 depicted strong antimicrobial actions (MIC: 4.8 µg/mL against both bacterial strains) and also had the lowest energy gap (3.24 eV), higher softness (0.309 eV), and lesser hardness (1.62 eV). Overall, when we compare qualitative and quantitative antimicrobial results, it is been very clear that compounds with dibromo substitutions on imidazopyridine (IMP) rings would act as better antimicrobial agents than those with -H at the eighth position on the IMP ring. Furthermore, substituents of higher electronegativities would tend to enhance the biological activities of dibromo-IMP compounds. DFT properties were also well comparable to this trend and overall, we can say that the electronic behavior of compounds under investigation has key roles in their bioactivities.


Volume of the Human Hippocampus and Clinical Response Following Electroconvulsive Therapy.

  • Leif Oltedal‎ et al.
  • Biological psychiatry‎
  • 2018‎

Hippocampal enlargements are commonly reported after electroconvulsive therapy (ECT). To clarify mechanisms, we examined if ECT-induced hippocampal volume change relates to dose (number of ECT sessions and electrode placement) and acts as a biomarker of clinical outcome.


Heterochromatin protein 1a functions for piRNA biogenesis predominantly from pericentric and telomeric regions in Drosophila.

  • Ryan Yee Wei Teo‎ et al.
  • Nature communications‎
  • 2018‎

In metazoan germline, Piwi-interacting RNAs (piRNAs) provide defence against transposons. Piwi-piRNA complex mediates transcriptional silencing of transposons in nucleus. Heterochromatin protein 1a (HP1a) has been proposed to function downstream of Piwi-piRNA complex in Drosophila. Here we show that HP1a germline knockdown (HP1a-GLKD) leads to a reduction in the total and Piwi-bound piRNAs mapping to clusters and transposons insertions, predominantly in the regions close to telomeres and centromeres, resulting in derepression of a limited number of transposons from these regions. In addition, HP1a-GLKD increases the splicing of transcripts arising from clusters in above regions, suggesting HP1a also functions upstream to piRNA processing. Evolutionarily old transposons enriched in the pericentric regions exhibit significant loss in piRNAs targeting these transposons upon HP1a-GLKD. Our study suggests that HP1a functions to repress transposons in a chromosomal compartmentalised manner.


Resting State Functional Connectivity Biomarkers of Treatment Response in Mood Disorders: A Review.

  • Joseph J Taylor‎ et al.
  • Frontiers in psychiatry‎
  • 2021‎

There are currently no validated treatment biomarkers in psychiatry. Resting State Functional Connectivity (RSFC) is a popular method for investigating the neural correlates of mood disorders, but the breadth of the field makes it difficult to assess progress toward treatment response biomarkers. In this review, we followed general PRISMA guidelines to evaluate the evidence base for mood disorder treatment biomarkers across diagnoses, brain network models, and treatment modalities. We hypothesized that no treatment biomarker would be validated across these domains or with independent datasets. Results are organized, interpreted, and discussed in the context of four popular analytic techniques: (1) reference region (seed-based) analysis, (2) independent component analysis, (3) graph theory analysis, and (4) other methods. Cortico-limbic connectivity is implicated across studies, but there is no single biomarker that spans analyses or that has been replicated in multiple independent datasets. We discuss RSFC limitations and future directions in biomarker development.


Integrative analysis of lithium treatment associated effects on brain structure and peripheral gene expression reveals novel molecular insights into mechanism of action.

  • Amit Anand‎ et al.
  • Translational psychiatry‎
  • 2020‎

Lithium is a highly effective medication for bipolar disorder, but its mechanism of action remains unknown. In this study, brain MRI scans and blood samples for gene expression (total of 110 scans and 109 blood samples) were collected from 21 bipolar subjects before and after 2 and 8 weeks of lithium monotherapy and at the same time-points from untreated 16 healthy controls. We used linear mixed-effects models to identify brain structural features and genes with expression changed after lithium treatment, with correction for multiple testing, and correlated their concurrent changes to identify molecular pathways associated with lithium effects. There are significant increases in gray matter fraction, global cortical thickness, and the frontal and parietal cortices after 8 weeks of lithium treatment (corrected p < 0.05). Volume increases were also seen for putamen, hippocampus, thalamic nuclei, and thalamic substructures. Several genes showed significant expression changes, and 14 gene pathways were identified for the present integration analysis. Of these, nine pathways had significant correlations with structural changes (FDR < 0.05). Three neurotrophy-related pathways (GDNF family of ligands, NFAT immune-response, and p53-signaling pathway) correlated with structural changes in multiple regions. Mediation analysis showed that the sphingomyelin metabolism pathway is associated with HAM-D change (p < 0.01), and this effect is mediated via the volume of mediodorsal thalamus (p < 0.03). In summary, the integration of lithium effects on brain structural and peripheral gene expression changes revealed effects on several neurotrophic molecular pathways, which provides further insights into the mechanism of lithium action.


A qualitative assessment of perceptions and attitudes toward postoperative pain and opioid use in patients undergoing elective knee arthroscopy.

  • Amit Anand‎ et al.
  • Canadian journal of surgery. Journal canadien de chirurgie‎
  • 2022‎

Orthopedic surgeons routinely prescribe opioids to manage post-operative pain. In the face of an opioid epidemic, a one-size-fits-all approach to pain management is no longer appropriate. Patient-centred prescribing practices should be used by surgeons; however, little is known about what influences patient attitudes toward postoperative pain and its management to inform such practices. We sought to explore patient attitudes toward postsurgical pain management, including opioids.


Heat Shock Factor 5 Is Essential for Spermatogenesis in Zebrafish.

  • Jolly M Saju‎ et al.
  • Cell reports‎
  • 2018‎

Heat shock factors (Hsfs) are transcription factors that regulate responses to heat shock and other environmental stimuli. Four heat shock factors (Hsf1-4) have been characterized from vertebrates to date. In addition to stress response, they also play important roles in development and gametogenesis. Here, we study the fifth member of heat shock factor family, Hsf5, using zebrafish as a model organism. Mutant hsf5-/- males, generated by CRISPR/Cas9 technique, were infertile with drastically reduced sperm count, increased sperm head size, and abnormal tail architecture, whereas females remained fertile. We show that Hsf5 is required for progression through meiotic prophase 1 during spermatogenesis as suggested by the accumulation of cells in the leptotene and zygotene-pachytene stages and increased apoptosis in post-meiotic cells. hsf5-/- mutants show gonadal misregulation of a substantial number of genes with roles in cell cycle, apoptosis, protein modifications, and signal transduction, indicating an important role of Hsf5 in early stages of spermatogenesis.


Genetic and environment effects on structural neuroimaging endophenotype for bipolar disorder: a novel molecular approach.

  • Bo Hu‎ et al.
  • Translational psychiatry‎
  • 2022‎

We investigated gene-environment effects on structural brain endophenotype in bipolar disorder (BD) using a novel method of combining polygenic risk scores with epigenetic signatures since traditional methods of examining the family history and trauma effects have significant limitations. The study enrolled 119 subjects, including 55 BD spectrum (BDS) subjects diagnosed with BD or major depressive disorder (MDD) with subthreshold BD symptoms and 64 non-BDS subjects comprising 32 MDD subjects without BD symptoms and 32 healthy subjects. The blood samples underwent genome-wide genotyping and methylation quantification. We derived polygenic risk score (PRS) and methylation profile score (MPS) as weighted summations of risk single nucleotide polymorphisms and methylation probes, respectively, which were considered as molecular measures of genetic and environmental risks for BD. Linear regression was used to relate PRS, MPS, and their interaction to 44 brain structure measures quantified from magnetic resonance imaging (MRI) on 47 BDS subjects, and the results were compared with those based on family history and childhood trauma. After multiplicity corrections using false discovery rate (FDR), MPS was found to be negatively associated with the volume of the medial geniculate thalamus (FDR = 0.059, partial R2 = 0.208). Family history, trauma scale, and PRS were not associated with any brain measures. PRS and MPS show significant interactions on whole putamen (FDR = 0.09, partial R2 = 0.337). No significant gene-environment interactions were identified for the family history and trauma scale. PRS and MPS generally explained greater proportions of variances of the brain measures (range of partial R2 = [0.008, 0.337]) than the clinical risk factors (range = [0.004, 0.228]).


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