Drosophila melanogaster White Mutant w1118 Undergo Retinal Degeneration

RNA interference-mediated knockdown of eye coloration genes in the western tarnished plant bug (Lygus hesperus Knight)

Insect eye coloration arises from the accumulation of various pigments. A number of genes that function in the biosynthesis (vermilion, cinnabar, and cardinal) and importation (karmoisin, white, scarlet, and brown) of these pigments, and their precursors, have been identified in diverse species and used as markers for transgenesis and gene editing. To examine their suitability as visible markers in Lygus hesperus Knight (western tarnished plant bug), transcriptomic data were screened for sequences exhibiting homology with the Drosophila melanogaster proteins. Complete open reading frames encoding putative homologs for all seven genes were identified. Bioinformatic-based sequence and phylogenetic analyses supported initial annotations as eye coloration genes. Consistent with their proposed role, each of the genes was expressed in adult heads as well as throughout nymphal and adult development. Adult eyes of those injected with double-stranded RNAs (dsRNAs) for karmoisin, vermilion, cinnabar, cardinal, and scarlet were characterized by a red band along the medial margin extending from the rostral terminus to the antenna. In contrast, eyes of insects injected with dsRNAs for both white and brown were a uniform light brown. White knockdown also produced cuticular and behavioral defects. Based on its expression profile and robust visible phenotype, cardinal would likely prove to be the most suitable marker for developing gene editing methods in Lygus species.

Efficacy and safety of a novel nitric oxide generator for the treatment of neonatal pulmonary hypertension: Experimental and clinical studies

Persistent pulmonary hypertension of the newborn (PPHN) is a complex pathology resulting from a failure of the post-natal reduction in pulmonary vascular resistance leading to hypoxemia. The standard therapy is inhaled Nitric Oxide (NO) improving oxygenation but its availability is limited, especially in hospitals with restricted financial resources. We evaluated the efficacy and safety of a new device generating NO (TAS + PLUS), in three experimental piglet models of pulmonary hypertension (PH), and we later tested its application in a pilot study of newborn patients suffering from PPHN. Piglets with experimentally induced PH showed a decrease in pulmonary arterial pressure (PAP) after breathing NO. Both acute and chronic exposure of piglets and rats did not cause any adverse effect in blood gas levels and biological parameters. A pilot study including 32 patients suffering from PPHN showed an increase in oxygen saturation (SatO₂) and partial pressure of oxygen in arterial blood (PaO₂) leading to a decrease of Oxygenation Index (OI) after compassionate treatment with NO from TAS + PLUS device. The device showed effectiveness and safety both in experimental PH and in the clinical setting. Therefore, it represents an excellent alternative for PPHN management in conditions where commercial NO is unavailable.

Blue light induces a neuroprotective gene expression program in Drosophila photoreceptors

BACKGROUND

Light exposure induces oxidative stress, which contributes to ocular diseases of aging. Blue light provides a model for light-induced oxidative stress, lipid peroxidation and retinal degeneration in Drosophila melanogaster. In contrast to mature adults, which undergo retinal degeneration when exposed to prolonged blue light, newly-eclosed flies are resistant to blue light-induced retinal degeneration. Here, we sought to characterize the gene expression programs induced by blue light in flies of different ages to identify neuroprotective pathways utilized by photoreceptors to cope with light-induced oxidative stress.

RESULTS

To identify gene expression changes induced by blue light exposure, we profiled the nuclear transcriptome of Drosophila photoreceptors from one- and six-day-old flies exposed to blue light and compared these with dark controls. Flies were exposed to 3 h blue light, which increases levels of reactive oxygen species but does not cause retinal degeneration. We identified substantial gene expression changes in response to blue light only in six-day-old flies. In six-day-old flies, blue light induced a neuroprotective gene expression program that included upregulation of stress response pathways and downregulation of genes involved in light response, calcium influx and ion transport. An intact phototransduction pathway and calcium influx were required for upregulation, but not downregulation, of genes in response to blue light, suggesting that distinct pathways mediate the blue light-associated transcriptional response.

CONCLUSION

Our data demonstrate that under phototoxic conditions, Drosophila photoreceptors upregulate stress response pathways and simultaneously, downregulate expression of phototransduction components, ion transporters, and calcium channels. Together, this gene expression program both counteracts the calcium influx resulting from prolonged light exposure, and ameliorates the oxidative stress resulting from this calcium influx. Thus, six-day-old flies can withstand up to 3 h blue light exposure without undergoing retinal degeneration. Developmental transitions during the first week of adult Drosophila life lead to an altered gene expression program in photoreceptors that includes reduced expression of genes that maintain redox and calcium homeostasis, reducing the capacity of six-day-old flies to cope with longer periods (8 h) of light exposure. Together, these data provide insight into the neuroprotective gene regulatory mechanisms that enable photoreceptors to withstand light-induced oxidative stress.

Biogenesis of zinc storage granules in Drosophila melanogaster

Membrane transporters and sequestration mechanisms concentrate metal ions differentially into discrete subcellular microenvironments for use in protein cofactors, signalling, storage or excretion. Here we identify zinc storage granules as the insect's major zinc reservoir in principal Malpighian tubule epithelial cells of Drosophila melanogaster The concerted action of Adaptor Protein-3, Rab32, HOPS and BLOC complexes as well as of the white-scarlet (ABCG2-like) and ZnT35C (ZnT2/ZnT3/ZnT8-like) transporters is required for zinc storage granule biogenesis. Due to lysosome-related organelle defects caused by mutations in the homologous human genes, patients with Hermansky-Pudlak syndrome may lack zinc granules in beta pancreatic cells, intestinal paneth cells and presynaptic vesicles of hippocampal mossy fibers.