Tiny microRNAs Fine-Tune Amyotrophic Lateral Sclerosis Regulation

Progressing muscle wasting and dramatic neurodegeneration of upper and lower motor neurons are the initial symptoms of amyotrophic lateral sclerosis (ALS) that eventually cause aetiology or death in quick succession. The functional mechanism of ALS is non-cell autonomous but it strongly influences on non-neural cells including microglia, astrocyte muscles and T cell. In ALS, neurodegeneration is triggered by at least four gene mutations that are not related to any classical signalling pathways, molecular mechanism or known cellular ingredients. MicroRNA is endogenous tiny non-coding RNA, which is required for fine-tuning or micromanaging protein expression post-transcriptionally. In this review, we identified numerous microRNAs and their possible targets in ALS-related genes. These microRNAs misprocess ALS-related protein-coding genes via microRNA-gene circuits. This result sheds a strong link between microRNA and ALS genes. The mechanistic insight of multiple microRNAs related to ALS is required to treat neuro-inflammation and neuro-degradation. It is proposed that the micro-regulation of multiple microRNAs is involved in generation of unique neuroprotective agent against ALS. Therefore, a classical and novel microRNA-mediated therapy might unravel an alternative strategy for ALS-related neurodegeneration. This strategy indeed implicates real promises to illustrate a unique impact for ALS cure

Long Noncoding RNAs are Frontier Breakthrough of RNA World and RNAi-based Gene Regulation

General complexities in versatile animals are not always proportional to their genome size. A notable example is that the salamander genome size is 15-fold larger than that of human, which mostly contains unfolded “junk DNA.” A vast portion of this non-protein-coding unfolded DNA undergoes transcriptional regulation and produces a large number of long noncoding RNAs (lncRNAs). LncRNAs play key roles in gene expression and therapies of different human diseases. Recently, novel lncRNAs and their function on the silencing or activation of a particular gene(s) are regularly being discovered. Another important component of gene regulation is high packing of chromatin, which is composed of mainly repetitive sequences with negligible coding potential. In particular, an epigenetic marker determines the state of the gene associated with it, whether the gene will be expressed or silenced. Here, we elaborately discuss the biogenesis pathway of lncRNAs as well as their mechanism of action and role in gene silencing and regulation, including RNA interference. Moreover, several lncRNAs are the common precursors of small regulatory RNAs. It is thus becoming increasingly clear that lncRNAs can function via numerous paradigms as key regulatory molecules in different organisms

Interaction Map and Selection of microRNA Targets in Parkinson's Disease-Related Genes

Parkinson's disease (PD) is a complex multigenic neurodisorder frequently occurring in elderly persons. To investigate noncoding tiny microRNA mediated gene regulation, miRanda (version 1.0b) was used to predict human miRNA target sites on selected 29 genes related to PD. To verify output generated from miRanda, a similar analysis was performed only for microRNA target sites in 3′UTR using TargetScan (version 5.1). Data extracted by miRanda elucidates the mode of microRNA action based on the location of target sites in the Parkinson genes. Sites prone to action of multiple miRNAs were identified as “hot spots.” Important properties of each miRNA including multiplicity and cooperativity appear to contribute towards a complex interplay between miRNAs and their targets. Two sets of predicted results were explored for the occurrence of target sites of 112 miRNAs expressed in midbrain. Overall, convergence of results predicted by two algorithms revealed that 48 target sites for midbrain-specific miRNA occur in close proximity in 9 genes. This study will pave a way for selection of potential miRNA candidates for Parkinson's disease-related genes for quick therapeutic applications and diagnosis

Revue du Marche Commun no. 78 = Review of the Common Market March 1965 No. 78

Argonaute family proteins are well conserved among all organisms. Its role in mitotic cell cycle progression and apoptotic cell elimination is poorly understood. Earlier we have established the contribution of Ago-1 in cell cycle control related to G2/M cyclin in Drosophila. Here we have extended our study in understanding the relationship of Ago-1 in regulating apoptosis during Drosophila development. Apoptosis play a critical role in controlling organ shape and size during development of multi cellular organism. Multifarious regulatory pathways control apoptosis during development among which highly conserved JNK (c-Jun N-terminal kinase) pathway play a crucial role. Here we have over expressed Ago-1 in Drosophila eye and brain by employing UAS (upstream activation sequence)-GAL4 system under the expression of eye and brain specific driver. Over expression of Ago-1 resulted in reduced number of ommatidia in the eye and produced smaller size brain in adult and larval Drosophila. A drastic reversal of the phenotype towards normal was observed upon introduction of a single copy of the dominant negative mutation of basket (bsk, Drosophila homolog of JNK) indicating an active and physical involvement of the bsk with Ago-1 in inducing developmental apoptotic process. Further study showed that Ago-1 stimulates phosphorylation of JNK through transforming growth factor-β activated kinase 1- hemipterous (Tak1-hep) axis of JNK pathway. JNK phosphorylation results in up regulation of pro-apoptotic genes head involution defective (hid), grim & reaper (rpr) and induces activation of Drosophila caspases (cysteinyl aspartate proteinases);DRONC (Death regulator Nedd2-like caspase), ICE (alternatively Drice, Death related ICE-like caspase) and DCP1 (Death caspase-1) by inhibiting apoptotic inhibitor protein DIAP1 (Death-associated inhibitor of apoptosis 1). Further, Ago-1 also inhibits miR-14 expression to trigger apoptosis. Our findings propose that Ago-1 acts as a key regulator in controlling cell death, tumor regression and stress response in metazoan providing a constructive bridge between RNAi machinery and cell death

Heterochromatic silencing and HP1 localization in Drosophila are dependent on the RNAi machinery

Genes normally resident in euchromatic domains are silenced when packaged into heterochromatin, as exemplified in Drosophila melanogaster by position effect variegation (PEV). Loss-of-function mutations resulting in suppression of PEV have identified critical components of heterochromatin, including proteins HP1, HP2, and histone H3 lysine 9 methyltransferase. Here, we demonstrate that this silencing is dependent on the RNA interference machinery, using tandem mini-white arrays and white transgenes in heterochromatin to show loss of silencing as a result of mutations in piwi, aubergine, or spindle-E (homeless), which encode RNAi components. These mutations result in reduction of H3 Lys9 methylation and delocalization of HP1 and HP2, most dramatically in spindle-E mutants

Effect of Benzothiazole based conjugates in causing apoptosis by Regulating p53, PTEN and MAP Kinase proteins affecting miR-195a and miR-101-1

<p>Abstract</p> <p>Background</p> <p>Hepatocellular carcinoma (HCC) accounts for majority of liver cancers and is the leading cause of cancer related death in Asia. Like any other cancer, HCC develops when there is a mutation to the cellular machinery that causes the cell to replicate at a higher rate and results in the loss of apoptosis. Therefore, a delicate balance between the expression of various genes involved in proliferation and apoptosis decide the ultimate fate of the cell to undergo rapid proliferation (cancer) or cell death.</p> <p>Results</p> <p>The benzothiazole based compounds exhibited effective cytotoxicity at 4 μM concentration and have shown G1 cell cycle arrest with decrease in levels of G1 cell cycle proteins such as cyclin D1 and Skp2. Involvement of tumour suppressor proteins such as PTEN and p53 was studied. Interestingly these compounds displayed decrease in the phosphorylated forms of AKT, p38 MAPK and ERK1/2 which play a vital role in cell proliferation. Compounds have exhibited strong and significant effect on the expression of micro RNAs such as miR-195a & miR-101-1 which regulate hepatic cell proliferation.</p> <p>Conclusions</p> <p>The cell cycle arrest and apoptotic inducing nature of these compounds was revealed by FACS, BrdU cell proliferation and tunel assays. Compounds affected both tumour suppressor proteins as well as proteins that are involved in active cell proliferation. Micro RNAs whose target is Cyclin D1 such as miR-195a and miR-101-1 that is required for growth of hepatoma cells was drastically affected. These compounds caused apoptosis by activating caspase-3 and PARP.</p

Chalcone-imidazolone conjugates induce apoptosis through DNA damage pathway by affecting telomeres

<p>Abstract</p> <p>Background</p> <p>Breast cancer is one of the most prevalent cancers in the world and more than one million women are diagnosed leading to 410,000 deaths every year. In our previous studies new chalcone-imidazolone conjugates were prepared and evaluated for their anticancer activity in a panel of 53 human tumor cell lines and the lead compounds identified were 6 and 8. This prompted us to investigate the mechanism of apoptotic event.</p> <p>Results</p> <p>Involvement of pro-apoptotic protein (Bax), active caspase-9 and cleavage of retinoblastoma protein was studied. Interestingly, the compounds caused upregulation of p21, check point proteins (Chk1, Chk2) and as well as their phosphorylated forms which are known to regulate the DNA damage pathway. Increased p53BP1 foci by immunolocalisation studies and TRF1 suggested the possible involvement of telomere and associated proteins in the apoptotic event. The telomeric protein such as TRF2 which is an important target for anticancer therapy against human breast cancer was extensively studied along with proteins involved in proper functioning of telomeres.</p> <p>Conclusions</p> <p>The apoptotic proteins such as Bax, active caspase-9 and cleaved RB are up-regulated in the compound treated cells revealing the apoptotic nature of the compounds. Down regulation of TRF2 and upregulation of the TRF1 as well as telomerase assay indicated the decrease in telomeric length revealing telomeric dysfunction and thereby controlling the rapid rate of cell proliferation. In summary, chalcone-imidazolone conjugates displayed significant DNA damage activity particularly at telomeres and caused both apoptosis and senescence-like growth arrest which suggested that these compounds have potential activity against breast carcinoma.</p