Gene expression dictates fundamental cellular processes and its de-regulation leads to pathological conditions. A key contributor to the fine-tuning of gene expression is Dicer, an RNA-binding protein (RBPs) that forms complexes and affects transcription by acting at the post-transcriptional level via the targeting of mRNAs by Dicer-produced small non-coding RNAs. This review aims to present the contribution of Dicer protein in a wide spectrum of human pathological conditions, including cancer, neurological, autoimmune, reproductive and cardiovascular diseases, as well as viral infections. Germline mutations of Dicer have been linked to Dicer1 syndrome, a rare genetic disorder that predisposes to the development of both benign and malignant tumors, but the exact correlation of Dicer protein expression within the different cancer types is unclear, and there are contradictions in the data. Downregulation of Dicer is related to Geographic atrophy (GA), a severe eye-disease that is a leading cause of blindness in industrialized countries, as well as to psychiatric and neurological diseases such as depression and Parkinson’s disease, respectively. Both loss and upregulation of Dicer protein expression is implicated in severe autoimmune disorders, including psoriasis, ankylosing spondylitis, rheumatoid arthritis, multiple sclerosis and autoimmune thyroid diseases. Loss of Dicer contributes to cardiovascular diseases and causes defective germ cell differentiation and reproductive system abnormalities in both sexes. Dicer can also act as a strong antiviral with a crucial role in RNA-based antiviral immunity. In conclusion, Dicer is an essential enzyme for the maintenance of physiology due to its pivotal role in several cellular processes, and its loss or aberrant expression contributes to the development of severe human diseases. Further exploitation is required for the development of novel, more effective Dicer-based diagnostic and therapeutic strategies, with the goal of new clinical benefits and better quality of life for patients.

Copper, a transition metal, is an essential component for normal growth and development. It acts as a critical co-factor of many enzymes that play key roles in diverse cellular processes. The present study attempts to investigate the regulatory functions decisively controlling copper trafficking during development and aging of the Drosophila model system. Hence, through engagement of the GAL4/UAS genetic platform and RNAi technology, we herein examined the in vivo significance of Atox1 and CCS genes, products of which pivotally govern cellular copper trafficking in fly tissue pathophysiology. Specifically, we analyzed the systemic effects of their targeted downregulation on the eye, wing, neuronal cell populations and whole-body tissues of the fly. Our results reveal that, in contrast to the eye, suppression of their expression in the wing leads to a notable increase in the percentage of malformed organs observed. Furthermore, we show that Atox1 or CCS gene silencing in either neuronal or whole-body tissues can critically affect the viability and climbing capacity of transgenic flies, while their double-genetic targeting suggests a rather synergistic mode of action of the cognate protein products. Interestingly, pharmacological intervention with the anti-cancer drug cisplatin indicates the major contribution of CCS copper chaperone to cisplatin's cellular trafficking, and presumably to tumor resistance often acquired during chemotherapy. Altogether, it seems that Atox1 and CCS proteins serve as tissue/organ-specific principal regulators of physiological Drosophila development and aging, while their tissue-dependent downregulation can provide important insights for Atox1 and CCS potential exploitation as predictive gene biomarkers of cancer-cell chemotherapy responses.

Drosophila brain has emerged as a powerful model system for the investigation of genes being related to neurological pathologies. To map the proteomic landscape of fly brain, in a high-resolution scale, we herein employed a nano liquid chromatography-tandem mass spectrometry technology, and high-content catalogues of 7,663 unique peptides and 2,335 single proteins were generated. Protein-data processing, through UniProt, DAVID, KEGG and PANTHER bioinformatics subroutines, led to fly brain-protein classification, according to sub-cellular topology, molecular function, implication in signaling and contribution to neuronal diseases. Given the importance of Ubiquitin Proteasome System (UPS) in neuropathologies and by using the almost completely reassembled UPS, we genetically targeted genes encoding components of the ubiquitination-dependent protein-degradation machinery. This analysis showed that driving RNAi toward proteasome components and regulators, using the GAL4-elav.L driver, resulted in changes to longevity and climbing-activity patterns during aging. Our proteomic map is expected to advance the existing knowledge regarding brain biology in animal species of major translational-research value and economical interest.