3-[[(3S)-1,2,3,4-Tetrahydroisoquinoline-3-Carbonyl]Amino]Propanoic Acid (THICAPA) Is Protective Against Aβ42-Induced Toxicity In Vitro and in an Alzheimer's Disease Drosophila

Alzheimer's disease (AD) is the most prevalent type of dementia globally. The accumulation of amyloid-beta (Aβ) extracellular senile plaques in the brain is one of the hallmark mechanisms found in AD. Aβ42 is the most damaging and aggressively aggregating Aβ isomer produced in the brain. Although Aβ42 has been extensively researched as a crucial peptide connected to the development of the characteristic amyloid fibrils in AD, the specifics of its pathophysiology are still unknown. Therefore, the main objective was to identify novel compounds that could potentially mitigate the negative effects of Aβ42. 3-[[(3S)-1,2,3,4-Tetrahydroisoquinoline-3-carbonyl]amino]propanoic acid (THICAPA) was identified as a ligand for Aβ42 and for reducing fibrillary Aβ42 aggregation. THICAPA also improved cell viability when administered to PC12 neuronal cells that were exposed to Aβ42. Additionally, this compound diminished Aβ42 toxicity in the current AD Drosophila model by rescuing the rough eye phenotype, prolonging the life span, and enhancing motor functions. Through next-generation RNA-sequencing, immune response pathways were downregulated in response to THICAPA treatment. Thus, this study suggests THICAPA as a possible disease-modifying treatment for AD.

Dosimetric Parameters Correlate with Taste Alterations in Head and Neck Radiotherapy

PURPOSE/OBJECTIVE(S)

Dysgeusia is an acute and chronic side effect of head and neck chemoradiation, with persistent taste dysfunction 1-2 years post radiotherapy occurring in 23-50% of patients. Several head and neck clinical trials set oral cavity mean doses between 30 to 40 Gy, however, there are no set guidelines accurately defining the composite structure and anatomic boundaries for the oral cavity or separating the tongue into specific quadrants. In this single institution cross sectional study, we sought to determine the effects of radiation doses to specific regions of the oral cavity and tongue on patient-reported long term dysgeusia. We hypothesize that radiation Dose to specific structures in the oral cavity will correlate with long-term dysgeusia in patients who have received head and neck radiotherapy.

MATERIALS/METHODS

Patients with primary head and neck cancer receiving definitive intensity modulated radiation therapy (RT) completed quality of life assessments that included patient-reported gustatory function, 1 year post RT. Dosimetric data from RT plans were collected for specific regions and organs at risk within the oral cavity. These structures included the anterior, posterior, superior and inferior tongue (OT), pharyngeal constrictors (as a surrogate for the corda-tympani) and the oral cavity. A forward binary logistic regression model was performed using these data points with scoring from the QLQ-H&N43 questionnaire subsection on taste (Q45) to determine the most predictive values for dysgeusia and the OR for moderate/severe alterations in taste.

RESULTS

A total of 78 patients were included in this study, of these patients, 63 had dosimetric data for the pharyngeal constrictors. The Oral Cavity Volume percentage receiving 50Gy (OC V50) and Pharyngeal Constrictors Volume percentage receiving 55Gy (PC V55) were the most predictive constraints for dysgeusia. (0.042, p = 0.011 and 0.041, p = 0.033). Holding all other variables constant in a forward binary logistic regression including 78 patients, the odds of having moderate to severe taste alterations increased by 56% (OR 1.045, 95% CI 1.012-1.079) for a 1% increase in OCV50. When analyzing the 68 patients with available pharyngeal constrictors data, taste alteration increased 20% for every 1% increase in PCV55 (OR 1.042, 95% CI 1.003-1.082). There was no correlation with taste alterations in any of the dose parameters tested (Dmax, mean and V50 up to V70) for superior, inferior, anterior or posterior regions of the tongue.

CONCLUSION

Dosimetric parameters for the oral cavity (OC V50) and pharyngeal constrictors (PC V55) were positively correlated with taste alterations, however, no other specific regions within the oral tongue predicted taste disfunction. Normal tissue complication probability modeling curves to identify OC V50 and PC V55 constraints for dysgeusia are needed.

Prognostic Value of Weekly Delta-Radiomics during MR-Linac Radiotherapy of Glioblastoma

PURPOSE/OBJECTIVE(S)

MRI after chemoradiotherapy (chemoRT) shows areas of presumed tumor growth in ≤ 50% of glioblastoma (GBM) patients, which can be true progression (TP) - tumor growth with poor treatment response, or pseudoprogression (PP) - edema and tumor necrosis with favorable treatment response. Patients with TP have median overall survival (OS) of only 7 months, while patients with PP have median OS of 36 months. However, on imaging, TP and PP are usually not discernible during treatment, making it difficult to adapt radiation for poor responders. The purpose of this study was to investigate the prognostic value of delta radiomic features from MR-Linac for GBM.

MATERIALS/METHODS

Using an IRB-approved prospective cohort of GBM patients undergoing 30 fractions of chemoRT to 60 Gy on a 0.35T MR-Linac, 2 regions of interest (ROI) were contoured on daily T2-weighted treatment set-up scans: 1) tumor/edema (lesion) and 2) post-surgical resection cavity (RC). The lesion ROI were used to calculate texture features: second order radiomics features based on the gray-level co-occurrence matrix (GLCM), gray-level size zone matrix (GLSZM), gray-level run length matrix (GLRLM), and neighborhood gray-tone difference matrix (NGTDM). Each of these describe the probability of spatial relationships of gray levels occurring within the ROI. Features from fraction 1 (pre-radiation) were subtracted from fractions 5, 10, 15, 25, and 30 to create delta features at 5 timepoints (D5-D30). Patient response was retrospectively defined as no progression (NP), TP, or PP. Supervised machine learning was utilized using a 500-tree random forest (RF) classification model with TP or PP as the outcome. Variable importance analysis was conducted by calculating the out-of-bag errors with multiple bootstrapped data sets. The most prognostic features were selected using the RF importance scores.

RESULTS

Thirty-six patients were screened for inclusion: 9 were excluded due to no T2 lesion (RC ROI only). Of the remaining 27 patients: 10 had NP, 11 had TP, and 6 had PP. Thirty-nine texture features, plus lesion volume and mean lesion intensity (for a total of 41 variables per time point) were calculated and included in the model. Of the 10 most prognostic features, 6 were from D10, suggesting that prognostic changes in the underlying lesion microenvironment are occurring within the first 10 fractions of treatment. The model selected GLSZM high gray-level zone emphasis (HGZE) D10, IBSI code 5GN9, as the most prognostic feature. The receiver operator characteristic (ROC) area under the curve (AUC) for GLSZM HGZE D10 was 0.94 (95% CI = 0.81-1.00).

CONCLUSION

Delta radiomic features extracted from MR-Linac imaging may predict between PP and TP in GBM patients during treatment, which is earlier than current methods. This could allow physicians to adapt/intensify treatment in real time for poorly responding patients. Future directions include analysis with a larger patient cohort and with additional MRI contrasts (MR-Linac multiparametric MRI).

Spectroscopic MRI Detects Occult Glioblastoma Invasion during Chemoradiation

PURPOSE/OBJECTIVE(S)

The standard of care for glioblastoma (GBM) includes surgical resection followed by adjuvant chemoradiation (chemoRT). Treatment margins are controversial since conventional imaging does not define the extent of infiltrating tumor cells. Whole-brain spectroscopic MRI (sMRI) allows for visualization of native metabolites in normal brain and tumor cells, and the relative choline to N-acetyl-aspartate ratio greater than 2 (rChoNAA>2) strongly correlates with the presence of occult GBM cells in otherwise normal-appearing brain. With an MRI-Linac, we are performing studies of adaptive radiotherapy to measure changes in cavity size, edema, and enhancement during chemoRT. We questioned whether rChoNAA>2 would change along with anatomical changes to inform clinical target volumes for adaptive chemoRT trials.

MATERIALS/METHODS

In a prospective study, 18 patients with primary GBM underwent daily MRI-guided chemoRT with standalone 3T sMRI generation of rChoNAA>2 maps at three timepoints before, during, and after chemoradiation. Conventional treatment volumes of T1 post-contrast and cavity (GTV2, i.e., boost) with or without FLAIR hyperintensity (GTV1) were compared to rChoNAA>2 volumes. DICE similarity coefficients were calculated to assess the spatial similarity of these volumes. Hausdorff distances were calculated to identify rChoNAA>2 extending beyond GTVs throughout the course of chemoradiation.

RESULTS

The mean GTV1 was 58.1 cc (range 0-251.4 cc), the mean GTV2 was 47.9 cc (range 0-139.9 cc), and the mean rChoNAA>2 volume was 31.1 cc (range 0-103.2 cc). rChoNAA>2 volumes did not significantly change over the course of chemoRT or correlate with measurement timepoint. The mean DICE similarity coefficient between GTV1 and rChoNAA>2 volumes was 0.39 (range 0-0.80), and the mean DICE similarity coefficient between GTV2 and rChoNAA>2 volumes was 0.29 (range 0-0.77). DICE similarity coefficients were significantly different from unity indicating spatial differences between rChoNAA>2 and conventional MRI volumes. The mean Hausdorff distances of rChoNAA>2 extending beyond GTV1 was 1.3 cm (range 0.7-2.1 cm), and the mean Hausdorff distances of rChoNAA>2 extending beyond GTV2 was 1.9 cm (range 0.8-2.9 cm), suggesting high-risk disease invading beyond what is visible on conventional MRI sequences.

CONCLUSION

Whole-brain sMRI with generation of rChoNAA>2 maps suggest conventional MRI does not fully capture the extent of disease in primary GBM throughout the course of chemoradiation. rChoNAA>2 maps often extend up to approximately 2 cm beyond conventional boost radiotherapy volumes. Further studies are ongoing to determine how sMRI can be used to adapt radiation target volumes during chemoradiation and escalate dose to occult disease.

Pattern Analysis of Daily Lesion Volume Trajectories for Early Prediction of Glioblastoma Progression During MR-Linac Radiotherapy

PURPOSE/OBJECTIVE(S)

Distinguishing between true progression (TP) and pseudoprogression (PP) post-radiotherapy (RT) is of paramount importance for treatment management of patients with glioblastoma (GBM). MR-Linac systems allow for daily monitoring of tumor changes throughout the course of RT. We hypothesized that the patterns of tumor volume change during RT may enable early prediction of treatment response.

MATERIALS/METHODS

Using an IRB-approved prospective cohort of GBM patients undergoing 30 fractions of chemoRT to 60 Gy on a 0.35T MR-Linac, tumor/edema (tumor lesion) regions of interest (ROI) were contoured on daily T2-weighted treatment set-up scans. The obtained tumor lesion (TL) volume changes during treatment were smoothed with a moving average Gaussian window over time. Non-negative Matrix Factorization (NMF) was applied to the data matrix D (N x F), containing the trajectories in its rows for each patient, where N is the number of patients analyzed and F is the number of fractions. NMF represents D as a linear combination of three temporal (hidden) patterns and their weights in each individual trajectory. The same analysis was performed for ΔD, containing the changes in volumes with reference to the first fraction. The calculated weights were scaled in [0, 1], expressed as probabilities (by ℓ1-normalization) and used as features in Linear Discriminant Analysis (LDA). The LDA model was trained to differentiate between no progression (NP), PP and TP, and assessed by leave-one-subject-out cross-validation.

RESULTS

Thirty-six patients were screened for inclusion: 9 were excluded due to no T2 lesion (resection cavity only). Of the remaining 27 GBM patients analyzed, 10 had no tumor growth on first post-RT diagnostic MRI, 6 were determined to have PP based on regression or long-term stability of findings, and 11 had TP due to continued progression of disease past 6 months, rapid patient death from disease, or tissue sampling showing active malignancy. With the use of only 2 features, LDA achieved an overall accuracy of 70.4% classifying correctly: 6 (60%), 4 (67%), and 9 (82%) patients with NP, PP, and TP, respectively. The temporal NMF patterns (monotonous decrease, rapid increase during the third part of the treatment, etc.) indicate that there is enough signal to classify patients' response based on the pattern tumor volume changes during RT.

CONCLUSION

We identified tumor dynamics' patterns during RT, indicative of differential behavior of tumor growth between TP and PP. Although with a limited number of patients, these initial results suggest that tumor volume changes during treatment may provide early markers of treatment response. This could allow physicians to adapt/intensify treatment in real time for poorly responding patients. Next steps include automating the process of real-time tumor volume monitoring by incorporating a deep learning solution for automatic volume delineation on daily treatment set-up scans.

p-Coumaric acid attenuates the effects of Aβ42 in vitro and in a Drosophila Alzheimer's disease model

Alzheimer's disease (AD) is the most common neurodegenerative condition in civilizations worldwide. The distinctive occurrence of amyloid-beta (Aβ) accumulation into insoluble fibrils is part of the disease pathophysiology with Aβ42 being the most toxic and aggressive Aβ species. The polyphenol, p-Coumaric acid (pCA), has been known to boost a number of therapeutic benefits. Here, pCA's potential to counteract the negative effects of Aβ42 was investigated. First, pCA was confirmed to reduce Aβ42 fibrillation using an in vitro activity assay. The compound was next examined on Aβ42-exposed PC12 neuronal cells and was found to significantly decrease Aβ42-induced cell mortality. pCA was then examined using an AD Drosophila melanogaster model. Feeding of pCA partially reversed the rough eye phenotype, significantly lengthened AD Drosophila's lifespan, and significantly enhanced the majority of the AD Drosophila's mobility in a sex-dependent manner. The findings of this study suggest that pCA may have therapeutic benefits for AD.

Behavioural Effects and RNA-seq Analysis of Aβ42-Mediated Toxicity in a Drosophila Alzheimer's Disease Model

Alzheimer's disease (AD) is the most common neurological ailment worldwide. Its process comprises the unique aggregation of extracellular senile plaques composed of amyloid-beta (Aβ) in the brain. Aβ42 is the most neurotoxic and aggressive of the Aβ42 isomers released in the brain. Despite much research on AD, the complete pathophysiology of this disease remains unknown. Technical and ethical constraints place limits on experiments utilizing human subjects. Thus, animal models were used to replicate human diseases. The Drosophila melanogaster is an excellent model for studying both physiological and behavioural aspects of human neurodegenerative illnesses. Here, the negative effects of Aβ42-expression on a Drosophila AD model were investigated through three behavioural assays followed by RNA-seq. The RNA-seq data was verified using qPCR. AD Drosophila expressing human Aβ42 exhibited degenerated eye structures, shortened lifespan, and declined mobility function compared to the wild-type Control. RNA-seq revealed 1496 genes that were differentially expressed from the Aβ42-expressing samples against the control. Among the pathways that were identified from the differentially expressed genes include carbon metabolism, oxidative phosphorylation, antimicrobial peptides, and longevity-regulating pathways. While AD is a complicated neurological condition whose aetiology is influenced by a number of factors, it is hoped that the current data will be sufficient to give a general picture of how Aβ42 influences the disease pathology. The discovery of molecular connections from the current Drosophila AD model offers fresh perspectives on the usage of this Drosophila which could aid in the discovery of new anti-AD medications.

SARS-CoV-2 genomic surveillance in Malaysia: displacement of B.1.617.2 with AY lineages as the dominant Delta variants and the introduction of Omicron during the fourth epidemic wave

OBJECTIVES

This study reported SARS-CoV-2 whole genome sequencing results from June 2021 to January 2022 from seven genome sequencing centers in Malaysia as part of the national surveillance program.

METHODS

COVID-19 samples that tested positive by reverse transcription polymerase chain reaction and with cycle threshold values <30 were obtained throughout Malaysia. Sequencing of SARS-CoV-2 complete genomes was performed using Illumina, Oxford Nanopore, or Ion Torrent platforms. A total of 6163 SARS-CoV-2 complete genome sequences were generated over the surveillance period. All sequences were submitted to the Global Initiative on Sharing All Influenza Data database.

RESULTS

From June 2021 to January 2022, Malaysia experienced the fourth wave of COVID-19 dominated by the Delta variant of concern, including the original B.1.617.2 lineage and descendant AY lineages. The B.1.617.2 lineage was identified as the early dominant circulating strain throughout the country but over time, was displaced by AY.59 and AY.79 lineages in Peninsular (west) Malaysia, and the AY.23 lineage in east Malaysia. In December 2021, pilgrims returning from Saudi Arabia facilitated the introduction and spread of the BA.1 lineage (Omicron variant of concern) in the country.

CONCLUSION

The changing trends of circulating SARS-CoV-2 lineages were identified, with differences observed between west and east Malaysia. This initiative highlighted the importance of leveraging research expertise in the country to facilitate pandemic response and preparedness.

Revised Annotation and Characterization of Novel Aedes albopictus miRNAs and Their Potential Functions in Dengue Virus Infection

Simple Summary

Aedes albopictus (Ae. albopictus) is an important vector of the dengue virus. Genetics and molecular studies of virus infection in mosquito vectors are important to uncover the basic biology of the virus. It has been reported that miRNAs are important and possess functional roles in virus infection in Ae. albopictus. Here, we report a comprehensive catalog of miRNAs using the latest genome version of Ae. albopictus. We discovered a total of 72 novel mature miRNAs, 44 of which were differentially expressed in C6/36 cells infected with the dengue virus. Target prediction analysis revealed that the differentially expressed miRNAs were involved in lipid metabolism and protein processing in the endoplasmic reticulum. Results from this study provide a valuable resource for researchers to study miRNAs in this mosquito vector, especially in host–virus interactions.

Abstract

The Asian tiger mosquito, Ae. albopictus, is a highly invasive species that transmits several arboviruses including dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV). Although several studies have identified microRNAs (miRNAs) in Ae. albopictus, it is crucial to extend and improve current annotations with both the newly improved genome assembly and the increased number of small RNA-sequencing data. We combined our high-depth sequence data and 26 public datasets to re-annotate Ae. albopictus miRNAs and found a total of 72 novel mature miRNAs. We discovered that the expression of novel miRNAs was lower than known miRNAs. Furthermore, compared to known miRNAs, novel miRNAs are prone to expression in a stage-specific manner. Upon DENV infection, a total of 44 novel miRNAs were differentially expressed, and target prediction analysis revealed that miRNA-target genes were involved in lipid metabolism and protein processing in endoplasmic reticulum. Taken together, the miRNA annotation profile provided here is the most comprehensive to date. We believed that this would facilitate future research in understanding virus–host interactions, particularly in the role of miRNAs.

Knockdown resistance (kdr) gene of Aedes aegypti in Malaysia with the discovery of a novel regional specific point mutation A1007G

BACKGROUND

Improved understanding of the molecular basis of insecticide resistance may yield new opportunities for control of relevant disease vectors. In this current study, we investigated the quantification responses for the phenotypic and genotypic resistance of Aedes aegypti populations from different states in Malaysia.

METHODS

We tested the insecticide susceptibility status of adult Ae. aegypti from populations of three states, Penang, Selangor and Kelantan (Peninsular Malaysia), against 0.25% permethrin and 0.25% pirimiphos-methyl using the World Health Organisation (WHO) adult bioassay method. Permethrin-resistant and -susceptible samples were then genotyped for domains II and III in the voltage-gated sodium channel (vgsc) gene using allele-specific polymerase chain reaction (AS-PCR) for the presence of any diagnostic single-nucleotide mutations. To validate AS-PCR results and to identify any possible additional point mutations, these two domains were sequenced.

RESULTS

The bioassays revealed that populations of Ae. aegypti from these three states were highly resistant towards 0.25% permethrin and 0.25% pirimiphos-methyl. Genotyping results showed that three knockdown (kdr) mutations (S989P, V1016G and F1534C) were associated with pyrethroid resistance within these populations. The presence of a novel mutation, the A1007G mutation, was also detected.

CONCLUSIONS

This study revealed the high resistance level of Malaysian populations of Ae. aegypti to currently used insecticides. The resistance could be due to the widespread presence of four kdr mutations in the field and this could potentially impact the vector control programmes in Malaysia and alternative solutions should be sought.

Dual inhibition of anti-apoptotic proteins BCL-XL and MCL-1 enhances cytotoxicity of Nasopharyngeal carcinoma cells

One of the many strategies that cancer cells evade death is through up-regulation of the BCL-2 anti-apoptotic proteins. Hence, these proteins have become attractive therapeutic targets. Given that different cell populations rely on different anti-apoptotic proteins for survival, it is crucial to determine which proteins are important for Nasopharyngeal carcinoma (NPC) cell survival. Here we determined the survival requirements for the NPC cells using a combination of the CRISPR/Cas9 technique and selective BH3-mimetics. A human apoptosis RT² Profiler PCR Array was first employed to profile the anti-apoptotic gene expressions in NPC cell lines HK-1 and C666-1. The HK-1 cells expressed all the anti-apoptotic genes (MCL-1, BFL-1, BCL-2, BCL-XL, and BCL-w). Similarly, the C666-1 cells expressed all the anti-apoptotic genes except BFL-1 (undetectable level). Notably, both cell lines highly expressed MCL-1. Deletion of MCL-1 sensitized the NPC cells to BCL-XL selective inhibitor A-1331852, suggesting that MCL-1 and BCL-XL may be important for NPC cell survival. Co-inhibition of MCL-1 and BCL-2 with MCL-1 selective inhibitor S63845 and BCL-2 selective inhibitor ABT-199 inhibited NPC cell proliferation but the effect on cell viability was more profound with co-inhibition of MCL-1 and BCL-XL with S63845 and A-1331852, implying that MCL-1 and BCL-XL are crucial for NPC cell survival. Furthermore, co-inhibition of MCL-1 and BCL-XL inhibited the growth and invasion of NPC spheroids. Deletion of BFL-1 sensitized NPC cells to A-1331852 suggesting that BFL-1 may play a role in NPC cell survival. Taken together co-inhibition of BCL-XL and MCL-1/BFL-1 could be potential treatment strategies for NPC.

CTP synthase: the hissing of the cellular serpent

CTP biosynthesis is carried out by two pathways: salvage and de novo. CTPsyn catalyzes the latter. The study of CTPsyn activity in mammalian cells began in the 1970s, and various fascinating discoveries were made regarding the role of CTPsyn in cancer and development. However, its ability to fit into a cellular serpent-like structure, termed 'cytoophidia,' was only discovered a decade ago by three independent groups of scientists. Although the self-assembly of CTPsyn into a filamentous structure is evolutionarily conserved, the enzyme activity upon this self-assembly varies in different species. CTPsyn is required for cellular development and homeostasis. Changes in the expression of CTPsyn cause developmental changes in Drosophila melanogaster. A high level of CTPsyn activity and formation of cytoophidia are often observed in rapidly proliferating cells such as in stem and cancer cells. Meanwhile, the deficiency of CTPsyn causes severe immunodeficiency leading to immunocompromised diseases caused by bacteria, viruses, and parasites, making CTPsyn an attractive therapeutic target. Here, we provide an overview of the role of CTPsyn in cellular and disease perspectives along with its potential as a drug target.

Alleviatory effects of Danshen, Salvianolic acid A and Salvianolic acid B on PC12 neuronal cells and Drosophila melanogaster model of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Danshen water extract (DWE), obtained from the Salvia miltiorrhiza Bunge (Family Lamiaceae) root, is usually employed in Chinese traditional medicine as treatment to cardiovascular ailments and cerebrovascular diseases. Intriguingly, the extract was also found to contain vast beneficial properties in Alzheimer's disease (AD) treatment.

AIM OF THE STUDY

Alzheimer's disease is the most significant type of neurodegenerative disorder plaguing societies globally. Its pathogenesis encompasses the hallmark aggregation of amyloid-beta (Aβ). Of all the Aβ oligomers formed in the brain, Aβ42 is the most toxic and aggressive. Despite this, the mechanism behind this disease remains elusive. In this study, DWE, and its major components, Salvianolic acid A (SalA) and Salvianolic acid B (SalB) were tested for their abilities to attenuate Aβ42's toxic effects.

METHODS

The composition of DWE was determined via Ultra-Performance Liquid Chromatography (UPLC). DWE, SalA and SalB were first verified for their capability to diminish Aβ42 fibrillation using an in vitro activity assay. Since Aβ42 aggregation results in neuronal degeneration, the potential Aβ42 inhibitors were next evaluated on Aβ42-exposed PC12 neuronal cells. The Drosophila melanogaster AD model was then employed to determine the effects of DWE, SalA and SalB.

RESULTS

DWE, SalA and SalB were shown to be able to reduce fibrillation of Aβ42. When tested on PC12 neuronal cells, DWE, SalA and SalB ameliorated cells from cell death associated with Aβ42 exposure. Next, DWE and its components were tested on the Drosophila melanogaster AD model and their rescue effects were further characterized. The UPLC analysis showed that SalA and SalB were present in the brains and bodies of Drosophila after DWE feeding. When human Aβ42 was expressed, the AD Drosophila exhibited degenerated eye structures known as the rough eye phenotype (REP), reduced lifespan and deteriorated locomotor ability. Administration of DWE, SalA and SalB partially reverted the REP, increased the age of AD Drosophila and improved most of the mobility of AD Drosophila.

CONCLUSION

Collectively, DWE and its components may have therapeutic potential for AD patients and possibly other forms of brain diseases.

Ethyl caffeate ameliorated amyloid-beta42 protein-associated toxicity in PC12 cells and Drosophila melanogaster

AIM

Alzheimer's disease (AD) is the most pervasive neurodegenerative disorder in societies globally. Till now, the mechanism behind this disease is still equivocal. Amyloid-beta42 protein (Aβ42), the most toxic and aggressive Aβ species, is the main focus of this study. The naturally occurring ethyl caffeate (EC) is associated with various medicinal properties. Here, EC was tested for its protective properties against Aβ42's toxic effects.

METHODS

As treatment of Aβ42 has been shown to cause neuronal cell death, EC was first screened with Aβ42-incubated PC12 neuronal cells. Next, the compound was tested on the Drosophila melanogaster AD model using the rough eye phenotype assay, lifespan assay and negative geotaxis assay.

RESULTS

EC ameliorated PC12 cells from cell death linked to Aβ42 exposure. Using Drosophila expressing human Aβ42, feeding of EC was able to partially rescue the rough eye phenotype, lengthen the lifespan of AD Drosophila and enhanced the mobility of middle-aged AD Drosophila.

CONCLUSION

Overall, the results of this study showed that EC might possess therapeutic properties for AD. Geriatr Gerontol Int 2021; ••: ••-••.

Data on RNA-seq analysis of Drosophila melanogaster during ageing

Ageing is defined as gradual decline of physiological, cellular and molecular state of an organism with time. The age-associated cell dysfunctions usually cause chronic diseases such as diabetes, cancers and other age-related diseases. Many of the genes and pathways involved in ageing are conserved in different species. These genes and pathways have been categorised into nine cellular and molecular hallmarks, namely, genomic instability, telomere attrition, loss of proteostasis, mitochondrial dysfunction, epigenetic alterations, deregulated nutrient sensing, stem cell exhaustion, cellular senescence and altered intercellular communication. Despite countless studies on ageing, the molecular mechanism of ageing is poorly understood. Here, we performed genome wide transcriptome mapping of ageing process in D. melanogaster. In which, transcriptomic analysis conducted on the 1 day and 60 days flies. Illumina Hiseq platform were used to generate raw data. Afterwards, further analysis including differential expression analysis, GO classification and KEGG pathway enrichment analysis were performed. The raw data were uploaded to SRA database and the BioProject ID is PRJNA718442. These data provide the basis for future research in order to discover the genes and pathways involved in ageing.

Identification and characterization of long noncoding RNAs and their association with acquisition of blood meal in Culex quinquefasciatus

The Southern house mosquito, Culex quinquefasciatus (Cx. quinquefasciatus) is an important vector that transmit multiple diseases including West Nile encephalitis, Japanese encephalitis, St. Louis encephalitis and lymphatic filariasis. Long noncoding RNAs (lncRNAs) involve in many biological processes such as development, infection, and virus-host interaction. However, there is no systematic identification and characterization of lncRNAs in Cx. quinquefasciatus. Here, we report the first lncRNA identification in Cx. quinquefasciatus. By using 31 public RNA-seq datasets, a total of 4763 novel lncRNA transcripts were identified, of which 3591, 569, and 603 were intergenic, intronic, and antisense respectively. Examination of genomic features revealed that Cx. quinquefasciatus shared similar characteristics with other species such as short in length, low GC content, low sequence conservation, and low coding potential. Furthermore, compared to protein-coding genes, Cx. quinquefasciatus lncRNAs had lower expression values, and tended to be expressed in temporally specific fashion. In addition, weighted correlation network and functional annotation analyses showed that lncRNAs may have roles in blood meal acquisition of adult female Cx. quinquefasciatus mosquitoes. This study presents the first systematic identification and analysis of Cx. quinquefasciatus lncRNAs and their association with blood feeding. Results generated from this study will facilitate future investigation on the function of Cx. quinquefasciatus lncRNAs.

Danshen (Salvia miltiorrhiza) water extract shows potential neuroprotective effects in Caenorhabditis elegans

ETHNOPHARMACOLOGICAL RELEVANCE

Danshen, is a traditional Chinese medicine obtained from the dried root and rhizome of Salvia miltiorrhiza Bunge. It is known to be used for neurological disorder including for Alzheimer's disease (AD). This study uncovers the effect of Danshen water extract on the Alzheimer's disease model of C.elegans.

MATERIAL AND METHODS

The composition of Danshen water extract was determined using (High Performance Liquid Chromatography (HPLC). Then Thioflavin T assay was used to determined if Danshen water extract could prevent the aggregation of amyloid-β peptide (Aβ). Alzheimer's disease C.elegans model was used to determine the effect of Danshen water extract. Finally, the reactive oxygen species (ROS) was determined using the 2,7-dichlorofuorescein diacetate method.

RESULTS

In this study, we found that standardized Danshen water extract that contains danshensu (1.26%), salvianolic acid A (0.35%) and salvianolic acid B (2.21%) are able to bind directly to Aβ and prevents it from aggregating. The IC₅₀ for the inhibition of Aβ aggregation by Danshen water extract was 0.5 mg/ml. In the AD model of C.elegans, Danshen water extract managed to alleviates the paralysis phenotype. Furthermore, the administration of Danshen water extract displayed antioxidant properties toward the Aβ-induced oxidative stress.

CONCLUSIONS

AD is a widespread neurodegenerative disease attributed to the accumulation of extracellular plaques comprising Aβ. Danshen water extract could significantly reduce the progress of paralysis in the AD model of C. elegans, showing promising results with its antioxidant properties. It can be concluded that Danshen water extract could potentially serve as a therapeutic for AD.

Genome-wide identification of Aedes albopictus long noncoding RNAs and their association with dengue and Zika virus infection

The Asian tiger mosquito, Aedes albopictus (Ae. albopictus), is an important vector that transmits arboviruses such as dengue (DENV), Zika (ZIKV) and Chikungunya virus (CHIKV). Long noncoding RNAs (lncRNAs) are known to regulate various biological processes. Knowledge on Ae. albopictus lncRNAs and their functional role in virus-host interactions are still limited. Here, we identified and characterized the lncRNAs in the genome of an arbovirus vector, Ae. albopictus, and evaluated their potential involvement in DENV and ZIKV infection. We used 148 public datasets, and identified a total of 10, 867 novel lncRNA transcripts, of which 5,809, 4,139, and 919 were intergenic, intronic and antisense respectively. The Ae. albopictus lncRNAs shared many characteristics with other species such as short length, low GC content, and low sequence conservation. RNA-sequencing of Ae. albopictus cells infected with DENV and ZIKV showed that the expression of lncRNAs was altered upon virus infection. Target prediction analysis revealed that Ae. albopictus lncRNAs may regulate the expression of genes involved in immunity and other metabolic and cellular processes. To verify the role of lncRNAs in virus infection, we generated mutations in lncRNA loci using CRISPR-Cas9, and discovered that two lncRNA loci mutations, namely XLOC_029733 (novel lncRNA transcript id: lncRNA_27639.2) and LOC115270134 (known lncRNA transcript id: XR_003899061.1) resulted in enhancement of DENV and ZIKV replication. The results presented here provide an important foundation for future studies of lncRNAs and their relationship with virus infection in Ae. albopictus.

Ae. albopictus is an important vector of arboviruses such as dengue and Zika viruses. Studies on virus-host interaction at gene expression and molecular level are crucial especially in devising methods to inhibit virus replication in Aedes mosquitoes. Previous reports have shown that, besides protein-coding genes, noncoding RNAs such as lncRNAs are also involved in virus-host interaction. In this study, we report a comprehensive catalog of novel lncRNA transcripts in the genome of Ae. albopictus. We also show that the expression of lncRNAs was altered upon infection with dengue and Zika. Additionally, depletion of certain lncRNAs resulted in increased replication of dengue and Zika; hence, suggesting potential association of lncRNAs in virus infection. Results of this study provide a new avenue to the investigation of mosquito-virus interactions, especially in the aspect of noncoding genes.

Lactobacillus plantarum DR7 improved brain health in aging rats via the serotonin, inflammatory and apoptosis pathways

Aging processes affect the brain in many ways, ranging from cellular to functional levels which lead to cognitive decline and increased oxidative stress. The aim of this study was to investigate the potentials of Lactobacillus plantarum DR7 on brain health including cognitive and memory functions during aging and the impacts of high fat diet during a 12-week period. Male Sprague-Dawley rats were separated into six groups: (1) young animals on normal diet (ND, (2) young animals on a high fat diet (HFD), (3) aged animals on ND, (4) aged animals on HFD, (5) aged animals on HFD and L. plantarum DR7 (10⁹ cfu/day) and (6) aged animals receiving HFD and lovastatin. To induce ageing, all rats in group 3 to 6 were injected sub-cutaneously at 600 mg/kg/day of D-galactose daily. The administration of DR7 has reduced anxiety accompanied by enhanced memory during behavioural assessments in aged-HFD rats (P<0.05). Hippocampal concentration of all three pro-inflammatory cytokines were increased during aging but reduced upon administration of both statin and DR7. Expressions of hippocampal neurotransmitters and apoptosis genes showed reduced expressions of indoleamine dioxygenase and P53 accompanied by increased expression of TPH1 in aged- HFD rats administered with DR7, indicating potential effects of DR7 along the pathways of serotonin and oxidative senescence. This study provided an insight into potentials of L. plantarum DR7 as a prospective dietary strategy to improve cognitive functions during aging. This study provided an insight into potentials of L. plantarum DR7 as a prospective dietary strategy to improve cognitive functions during aging.

The molecular mechanisms of probiotic strains in improving ageing bone and muscle of d-galactose-induced ageing rats

AIM

The aim of this study was to evaluate the molecular mechanisms of Lactobacillus strains in improving ageing of the musculoskeletal system.

METHODS AND RESULTS

The anti-ageing mechanism of three probiotics strains Lactobacillus fermentum DR9, Lactobacillus paracasei OFS 0291 and L. helveticus OFS 1515 were evaluated on gastrocnemius muscle and tibia of d-galactose-induced ageing rats. Upon senescence induction, aged rats demonstrated reduced antioxidative genes CAT and SOD expression in both bone and muscle compared to the young rats (P < 0·05). Strain L. fermentum DR9 demonstrated improved expression of SOD in bone and muscle compared to the aged rats (P < 0·05). In the evaluation of myogenesis-related genes, L. paracasei OFS 0291 and L. fermentum DR9 increased the mRNA expression of IGF-1; L. helveticus OFS 1515 and L. fermentum DR9 reduced the expression of MyoD, in contrast to the aged controls (P < 0·05). Protective effects of L. fermentum DR9 on ageing muscle were believed to be contributed by increased AMPK-α2 expression. Among the osteoclastogenesis genes studied, TNF-α expression was highly elevated in tibia of aged rats, while all three probiotics strains ameliorated the expression. Lactobacillus fermentum DR9 also reduced the expression of IL-6 and TRAP in tibia when compared to the aged rats (P < 0·05). All probiotics treatment resulted in declined proinflammatory cytokines IL-1β in muscle and bone.

CONCLUSIONS

Lactobacillus fermentum DR9 appeared to be the strongest strain in modulation of musculoskeletal health during ageing.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study demonstrated the protective effects of the bacteria on muscle and bone through antioxidative and anti-inflammatory actions. Therefore, L. fermentum DR9 may serve as a promising targeted anti-ageing therapy.

Lactobacillus Strains Alleviated Hyperlipidemia and Liver Steatosis in Aging Rats via Activation of AMPK

In this study, we hypothesized that different strains of Lactobacillus can alleviate hyperlipidemia and liver steatosis via activation of 5′ adenosine monophosphate-activated protein kinase (AMPK), an enzyme that is involved in cellular energy homeostasis, in aged rats. Male rats were fed with a high-fat diet (HFD) and injected with D-galactose daily over 12 weeks to induce aging. Treatments included (n = 6) (i) normal diet (ND), (ii) HFD, (iii) HFD-statin (lovastatin 2 mg/kg/day), (iv) HFD-Lactobacillus fermentum DR9 (10 log CFU/day), (v) HFD-Lactobacillus plantarum DR7 (10 log CFU/day), and (vi) HFD-Lactobacillus reuteri 8513d (10 log CFU/day). Rats administered with statin, DR9, and 8513d reduced serum total cholesterol levels after eight weeks (p < 0.05), while the administration of DR7 reduced serum triglycerides level after 12 weeks (p < 0.05) as compared to the HFD control. A more prominent effect was observed from the administration of DR7, where positive effects were observed, ranging from hepatic gene expressions to liver histology as compared to the control (p < 0.05); downregulation of hepatic lipid synthesis and β-oxidation gene stearoyl-CoA desaturase 1 (SCD1), upregulation of hepatic sterol excretion genes of ATP-binding cassette subfamily G member 5 and 8 (ABCG5 and ABCG8), lesser degree of liver steatosis, and upregulation of hepatic energy metabolisms genes AMPKα1 and AMPKα2. Taken altogether, this study illustrated that the administration of selected Lactobacillus strains led to improved lipid profiles via activation of energy and lipid metabolisms, suggesting the potentials of Lactobacillus as a promising natural intervention for alleviation of cardiovascular and liver diseases.

Ageing, Drosophila melanogaster and Epigenetics

Ageing is a phenomenon where the accumulation of all the stresses that alter the functions of living organisms, halter them from maintaining their physiological balance and eventually lead to death. The emergence of epigenetic tremendously contributed to the knowledge of ageing. Epigenetic changes in cells or tissues like deoxyribonucleic acid (DNA) methylation, modification of histone proteins, transcriptional modification and also the involvement of non-coding DNA has been documented to be associated with ageing. In order to study ageing, scientists have taken advantage of several potential organisms to aid them in their study. Drosophila melanogaster has been an essential model in establishing current understanding of the mechanism of ageing as they possess several advantages over other competitors like having homologues to more than 75% of human disease genes, having 50% of Drosophila genes are homologues to human genes and most importantly they are genetically amenable. Here, we would like to summarise the extant knowledge about ageing and epigenetic process and the role of Drosophila as an ideal model to study epigenetics in association with ageing process.

Lactic acid bacteria feeding reversed the malformed eye structures and ameliorated gut microbiota profiles of Drosophila melanogaster Alzheimer's Disease model

AIMS

To utilize transgenic GMR-Aβ42 Drosophila melanogaster as a model to evaluate potential Alzheimer's disease (AD)-reversal effects via the administration of lactic acid bacteria (LAB) strains, and associations of LAB with changes in gut microbiota profiles.

METHODS AND RESULTS

Wild type flies (Oregon-R) was crossed with glass multimer reporter-GAL4 (GMR-GAL4) to produce GMR-OreR (Control), while UAS-Aβ42 (#33769) crossed with GMR-GAL4 to produce transgenic Drosophila line that expressed Aβ42 (GMR-Aβ42). Feed containing seven different LAB strains (Lactobacillus paracasei 0291, Lactobacillus helveticus 1515, Lactobacillus reuteri CDV, Lactobacillus reuteri 8513d, Lactobacillus fermentum 8312, Lactobacillus casei Y, Lactobacillus sakei Probio65) were given to GMR-Aβ42 respectively, while feed without LAB strains were given to control and transgenic GMR-Aβ42.nf Drosophila lines. The morphology of the eyes was viewed with scanning electron microscopy (SEM). The changes in gut microbiota profiles associated with LAB were analyzed using 16s high throughput sequencing. Malformation of eye structures in transgenic GMR-Aβ42 Drosophila were reversed upon the administration of LAB strains, with more prevalent effects from Lactobacillus sakei Probio65 and Lactobacillus paracasei 0291. The GMR-Aβ42.nf group showed dominance of Wolbachia in the gut, a genus that was almost absent in the normal control group (P<0.05). The administration of L. sakei Probio65 and L. paracasei 0291 reduced the abundance of Wolbachia accompanied by increased abundance of Stenotrophomonas and Acetobacter (P<0.05), resembling the microbial profile of the control group.

CONCLUSIONS

L. sakei Probio65 and L. paracasei 0291 have more prominent effects in reversing malformed eye of transgenic GMR-Aβ42 Drosophila, and reducing the abundance of Wolbachia accompanied by an increased abundance of Stenotrophomonas and Acetobacter.

SIGNIFICANCE AND IMPACT OF THE STUDY

Potentials of LAB to prevent and/or alleviate the onset and pathogenesis of neurodegenerative diseases such as AD, supporting brain health strategies along the gut-brain axis.

Lactobacillus probiotics improved the gut microbiota profile of a Drosophila melanogaster Alzheimer's disease model and alleviated neurodegeneration in the eye

Alzheimer's disease (AD) is a progressive disease and one of the most common forms of neurodegenerative disorders. Emerging evidence is supporting the use of various strategies that modulate gut microbiota to exert neurological and psychological changes. This includes the utilisation of probiotics as a natural and dietary intervention for brain health. Here, we showed the potential AD-reversal effects of Lactobacillus probiotics through feeding to our Drosophila melanogaster AD model. The administration of Lactobacillus strains was able to rescue the rough eye phenotype (REP) seen in AD-induced Drosophila, with a more prominent effect observed upon the administration of Lactobacillus plantarum DR7 (DR7). Furthermore, we analysed the gut microbiota of the AD-induced Drosophila and found elevated levels of Wolbachia. The administration of DR7 restored the gut microbiota diversity of AD-induced Drosophila with a significant reduction in Wolbachia's relative abundance, accompanied by an increase of Stenotrophomonas and Acetobacter. Through functional predictive analyses, Wolbachia was predicted to be positively correlated with neurodegenerative disorders, such as Parkinson's, Huntington's and Alzheimer's diseases, while Stenotrophomonas was negatively correlated with these neurodegenerative disorders. Altogether, our data exhibited DR7's ability to ameliorate the AD effects in our AD-induced Drosophila. Thus, we propose that Wolbachia be used as a potential biomarker for AD.

Lactobacilli modulated AMPK activity and prevented telomere shortening in ageing rats

This study aimed to evaluate the anti-ageing effects of different strains of lactobacilli putative probiotics on an ageing rat model as induced by D-galactose and a high fat diet. Male Sprague-Dawley rats were fed with high fat diet (54% kcal fat) and injected with D-galactose daily for 12 weeks to induce ageing. The effects of putative probiotic strains on age-related impairment such as telomere length, plasma lipid peroxidation, hepatic 5'adenosine monophosphate-activated protein kinase (AMPK) expression, as well as endurance performance were evaluated. Administration of statin, Lactobacillus plantarum DR7 (LP-DR7), Lactobacillus fermentum DR9 (LF-DR9), and Lactobacillus reuteri 8513d (LR-8513d) significantly reduced the shortening of telomere and increased the expression of AMPK subunit-α1 (P<0.05). Plasma lipid peroxidation was lower (P<0.05) in groups administered with statin and LF-DR9 as compared to the control. AMPK subunit-α2 was elevated in rats administered with LP-DR7 as compared to the control (P<0.05). Using an in vivo ageing rat model, the current study has illustrated the potentials of lactobacilli putative probiotics in alleviation of age-related impairment in a strain-dependent manner.

Systematic identification and characterization of Aedes aegypti long noncoding RNAs (lncRNAs)

Long noncoding RNAs (lncRNAs) play diverse roles in biological processes. Aedes aegypti (Ae. aegypti), a blood-sucking mosquito, is the principal vector responsible for replication and transmission of arboviruses including dengue, Zika, and Chikungunya virus. Systematic identification and developmental characterisation of Ae. aegypti lncRNAs are still limited. We performed genome-wide identification of lncRNAs, followed by developmental profiling of lncRNA in Ae. aegypti. We identified a total of 4,689 novel lncRNA transcripts, of which 2,064, 2,076, and 549 were intergenic, intronic, and antisense respectively. Ae. aegypti lncRNAs share many characteristics with other species including low expression, low GC content, short in length, and low conservation. Besides, the expression of Ae. aegypti lncRNAs tend to be correlated with neighbouring and antisense protein-coding genes. A subset of lncRNAs shows evidence of maternal inheritance; hence, suggesting potential role of lncRNAs in early-stage embryos. Additionally, lncRNAs show higher tendency to be expressed in developmental and temporal specific manner. The results from this study provide foundation for future investigation on the function of Ae. aegypti lncRNAs.

Genome-wide identification and characterization of long intergenic noncoding RNAs in the regenerative flatworm Macrostomum lignano

The free-living flatworm Macrostoma lignano (M. lignano) is an emerging model organism for aging and regeneration research. Long intergenic non-coding RNAs (lincRNAs) have important roles in many biological processes such as aging, stem cell maintenance and differentiation. However, to date, there is no systematic identification of lincRNAs in M. lignano. By using public RNA-seq data, we identified a total of 2547 lincRNA transcripts in M. lignano genome. We discovered that M. lignano lincRNAs shared many characteristics with other species such as shorter in length, lower GC content, and lower in expression compared to protein-coding genes. Unlike protein-coding genes, M. lignano lincRNAs showed higher tendency to be expressed in temporal and region-specific fashion. Additionally, co-expression network analysis and functional enrichment suggest that M. lignano lincRNAs have potential roles in regeneration. This study will provide important resources and pave the way for investigations on non-coding genes involved in aging and regeneration.

Lactobacillus sp. improved microbiota and metabolite profiles of aging rats

Aging is closely associated with altered gut function and composition, in which elderly were reported with reduced gut microbiota diversity and increased incidence of age-related diseases. Probiotics have been shown to exert beneficial health-promoting effects through modulation of intestinal microflora biodiversity, thus the effects of probiotics administration on D-galactose (D-gal) senescence-induced rat were evaluated based on the changes in gut microbiota and metabolomic profiles. Upon senescence induction, the ratio of Firmicutes/ Bacteroidetes was significantly lowered, while treatment with Lactobacillus helveticus OFS 1515 and L. fermentum DR9 increased the ratio at the phylum level (P < 0.05). Study on the genus level showed that L. paracasei OFS 0291 and L. helveticus OFS 1515 administration reduced Bacteroides, which are prominently opportunistic pathogens while L. fermentum DR9 treated rats promoted the proliferation of Lactobacillus compared to the aged rats (P < 0.05). Probiotics treatment did not alter fecal short-chain fatty acid (SCFA) profile, but an increase in acetate was observed in the D-gal rats. The analysis of fecal water-soluble metabolites showed that D-gal induced senescence caused great impact on amino acids metabolism such as urocanic acid, citrulline, cystamine and 5-oxoproline, which could serve as potential aging biomarkers. Treatment with probiotics ameliorated these metabolites in a strain-specific manner, whereby L. fermentum DR9 promoted antioxidative effect through upregulation of oxoproline, whereas both L. paracasei OFS 0291 and L. helveticus OFS 1515 restored the levels of reducing sugars, arabinose and ribose similar to the young rats. D-gal induced senescence did cause significant immunological alteration in the colon of aged rats however, all probiotic strains demonstrated immunomodulatory properties as L. paracasei OFS 0291, L. helveticus OFS 1515 and L. fermentum DR9 alleviated proinflammatory cytokines TNF-α, IFN-γ and IL-1β as well as IL-4 compared to the aged control (P < 0.05). Our study highlights the potential of probiotics as an anti-aging therapy through healthy gut modulation.

Ectopic miR-975 induces CTP synthase directed cell proliferation and differentiation in Drosophila melanogaster

CTP synthase (CTPSyn) is an essential metabolic enzyme, synthesizing precursors required for nucleotides and phospholipids production. Previous studies have also shown that CTPSyn is elevated in various cancers. In many organisms, CTPSyn compartmentalizes into filaments called cytoophidia. In Drosophila melanogaster, only its isoform C (CTPSynIsoC) forms cytoophidia. In the fruit fly's testis, cytoophidia are normally seen in the transit amplification regions close to its apical tip, where the stem-cell niche is located, and development is at its most rapid. Here, we report that CTPSynIsoC overexpression causes the lengthening of cytoophidia throughout the entirety of the testicular body. A bulging apical tip is found in approximately 34% of males overexpressing CTPSynIsoC. Immunostaining shows that this bulged phenotype is most likely due to increased numbers of both germline cells and spermatocytes. Through a microRNA (miRNA) overexpression screen, we found that ectopic miR-975 concurrently increases both the expression levels of CTPSyn and the length of its cytoophidia. The bulging testes phenotype was also recovered at a penetration of approximately 20%. However, qPCR assays reveal that CTPSynIsoC and miR-975 overexpression each provokes a differential response in expression of a number of cancer-related genes, indicating that the shared CTPSyn upregulation seen in either case is likely the cause of observed testicular overgrowth. This study presents the first instance of consequences of miRNA-asserted regulation upon CTPSyn in D. melanogaster, and further reaffirms the enzyme's close ties to germline cells overgrowth.

Assessment of Aedes albopictus reference genes for quantitative PCR at different stages of development

Members of the Aedes genus of mosquitoes are widely recognized as vectors of viral diseases. Ae.albopictus is its most invasive species, and are known to carry viruses such as Dengue, Chikugunya and Zika. Its emerging importance puts Ae.albopictus on the forefront of genetic interaction and evolution studies. However, a panel of suitable reference genes specific for this insect is as of now undescribed. Nine reference genes, namely ACT, eEF1-γ, eIF2α, PP2A, RPL32, RPS17, PGK1, ILK and STK were evaluated. Expression patterns of the candidate reference genes were observed in a total of seventeen sample types, separated by stage of development and age. Gene stability was inferred from obtained quantification data through three widely cited evaluation algorithms i.e. BestKeeper, geNorm, and NormFinder. No single gene showed a satisfactory degree of stability throughout all developmental stages. Therefore, we propose combinations of PGK and ILK for early embryos; RPL32 and RPS17 for late embryos, all four larval instars, and pupae samples; eEF1-γ with STK for adult males; eEF1-γ with RPS17 for non-blood fed females; and eEF1-γ with eIF2α for both blood-fed females and cell culture. The results from this study should be able to provide a more informed selection of normalizing genes during qPCR in Ae.albopictus.

Evaluation of reference genes at different developmental stages for quantitative real-time PCR in Aedes aegypti

The mosquito Aedes aegypti (Ae. aegypti) is the most notorious vector of illness-causing viruses such as Dengue, Chikugunya, and Zika. Although numerous genetic expression studies utilizing quantitative real-time PCR (qPCR) have been conducted with regards to Ae. aegypti, a panel of genes to be used suitably as references for the purpose of expression-level normalization within this epidemiologically important insect is presently lacking. Here, the usability of seven widely-utilized reference genes i.e. actin (ACT), eukaryotic elongation factor 1 alpha (eEF1α), alpha tubulin (α-tubulin), ribosomal proteins L8, L32 and S17 (RPL8, RPL32 and RPS17), and glyceraldeyde 3-phosphate dehydrogenase (GAPDH) were investigated. Expression patterns of the reference genes were observed in sixteen pre-determined developmental stages and in cell culture. Gene stability was inferred from qPCR data through three freely available algorithms i.e. BestKeeper, geNorm, and NormFinder. The consensus rankings generated from stability values provided by these programs suggest a combination of at least two genes for normalization. ACT and RPS17 are the most dependably expressed reference genes and therefore, we propose an ACT/RPS17 combination for normalization in all Ae. aegypti derived samples. GAPDH performed least desirably, and is thus not a recommended reference gene. This study emphasizes the importance of validating reference genes in Ae. aegypti for qPCR based research.

Drosophila melanogaster: Deciphering Alzheimer's Disease

Alzheimer's disease (AD) is the most widespread neurodegenerative disorder worldwide. Its pathogenesis involves two hallmarks: aggregation of amyloid beta (Aβ) and occurrence of neurofibrillary tangles (NFTs). The mechanism behind the disease is still unknown. This has prompted the use of animal models to mirror the disease. The fruit fly, Drosophila melanogaster has garnered considerable attention as an organism to recapitulate human disorders. With the ability to monopolise a multitude of traditional and novel genetic tools, Drosophila is ideal for studying not only cellular aspects but also physiological and behavioural traits of human neurodegenerative diseases. Here, we discuss the use of the Drosophila model in understanding AD pathology and the insights gained in discovering drug therapies for AD.

Argonaute: The executor of small RNA function

The discovery of small non-coding RNAs - microRNA (miRNA), short interfering RNA (siRNA) and PIWI-interacting RNA (piRNA) - represents one of the most exciting frontiers in biology specifically on the mechanism of gene regulation. In order to execute their functions, these small RNAs require physical interactions with their protein partners, the Argonaute (AGO) family proteins. Over the years, numerous studies have made tremendous progress on understanding the roles of AGO in gene silencing in various organisms. In this review, we summarize recent progress of AGO-mediated gene silencing and other cellular processes in which AGO proteins have been implicated with a particular focus on progress made in flies, humans and other model organisms as compliment.

Nucleotide synthesis is regulated by cytoophidium formation during neurodevelopment and adaptive metabolism

The essential metabolic enzyme CTP synthase (CTPsyn) can be compartmentalised to form an evolutionarily-conserved intracellular structure termed the cytoophidium. Recently, it has been demonstrated that the enzymatic activity of CTPsyn is attenuated by incorporation into cytoophidia in bacteria and yeast cells. Here we demonstrate that CTPsyn is regulated in a similar manner in Drosophila tissues in vivo. We show that cytoophidium formation occurs during nutrient deprivation in cultured cells, as well as in quiescent and starved neuroblasts of the Drosophila larval central nervous system. We also show that cytoophidia formation is reversible during neurogenesis, indicating that filament formation regulates pyrimidine synthesis in a normal developmental context. Furthermore, our global metabolic profiling demonstrates that CTPsyn overexpression does not significantly alter CTPsyn-related enzymatic activity, suggesting that cytoophidium formation facilitates metabolic stabilisation. In addition, we show that overexpression of CTPsyn only results in moderate increase of CTP pool in human stable cell lines. Together, our study provides experimental evidence, and a mathematical model, for the hypothesis that inactive CTPsyn is incorporated into cytoophidia.