The overexpression of DSP1 in neurons induces neuronal dysfunction and neurodegeneration phenotypes in Drosophila.

Dorsal switch protein 1(DSP1), a mammalian homolog of HMGB1, is firstly identified as a dorsal co-repressor in 1994. DSP1 contains HMG-box domain and functions as a transcriptional regulator in Drosophila melanogaster. It plays a crucial role in embryonic development, particularly in dorsal-ventral patterning during early embryogenesis, through the regulation of gene expression. Moreover, DSP1 is implicated in various cellular processes, including cell fate determination and tissue differentiation, which are essential for embryonic development. While the function of DSP1 in embryonic development has been relatively well-studied, its role in the adult Drosophila brain remains less understood. In this study, we investigated the role of DSP1 in the brain by using neuronal-specific DSP1 overexpression flies. We observed that climbing ability and life span are decreased in DSP1-overexpressed flies. Furthermore, these flies demonstrated neuromuscular junction (NMJ) defect, reduced eye size and a decrease in tyrosine hydroxylase (TH)-positive neurons, indicating neuronal toxicity induced by DSP1 overexpression. Our data suggest that DSP1 overexpression leads to neuronal dysfunction and toxicity, positioning DSP1 as a potential therapeutic target for neurodegenerative diseases.

Nesfatin-1 ameliorates pathological abnormalities in Drosophila hTau model of Alzheimer's disease.

In human Alzheimer's disease (AD), the aggregation of tau protein is considered a significant hallmark, along with amyloid-beta. The formation of neurofibrillary tangles due to aberrant phosphorylation of tau disrupts microtubule stability, leading to neuronal toxicity, dysfunction, and subsequent cell death. Nesfatin-1 is a neuropeptide primarily known for regulating appetite and energy homeostasis. However, the function of Nesfatin-1 in a neuroprotective role has not been investigated. In this study, we aimed to elucidate the effect of Nesfatin-1 on tau pathology using the Drosophila model system. Our findings demonstrate that Nesfatin-1 effectively mitigates the pathological phenotypes observed in Drosophila human Tau overexpression models. Nesfatin-1 overexpression rescued the neurodegenerative phenotypes in the adult fly's eye and bristle. Additionally, Nesfatin-1 improved locomotive behavior, neuromuscular junction formation, and lifespan in the hTau AD model. Moreover, Nesfatin-1 controls tauopathy by reducing the protein level of hTau. Overall, this research highlights the potential therapeutic applications of Nesfatin-1 in ameliorating the pathological features associated with Alzheimer's disease.

NUCB1 is required for proper insulin signaling to control longevity in Drosophila.

AIM: We examined the novel role of NUCB1(Nucleobindin-1) associated with longevity in Drosophila melanogaster. METHODS: We measured the lifespan, metabolic phenotypes, and mRNA levels of Drosophila insulin-like peptides (Dilps), the protein level of phosphorylated AKT, and the localization of FOXO and its target gene expressions in the NUCB1 knockdown condition. RESULTS: NUCB1 knockdown flies show an extended lifespan and metabolic phenotypes such as increased circulating glucose level and starvation resistance. The mRNA expression levels of Dilps and the protein level of phosphorylated AKT, a downstream component of insulin signaling, were decreased in NUCB1 knockdown flies compared with the control flies. Also, the nuclear localization of FOXO and its target gene expressions, such as d4E-BP and InR, were elevated. CONCLUSIONS: The results show that NUCB1 knockdown flies exhibits an extended lifespan. These findings suggest that NUCB1 modulates longevity through insulin signaling in Drosophila. Geriatr Gerontol Int 2024; 24: 486-492.

Proteasome inhibitors with pyrazole scaffolds from structure-based virtual screening.

We performed a virtual screen of ∼340 000 small molecules against the active site of proteasomes followed by in vitro assays and subsequent optimization, yielding a proteasome inhibitor with pyrazole scaffold. The pyrazole-scaffold compound displayed excellent metabolic stability and was highly effective in suppressing solid tumor growth in vivo. Furthermore, the effectiveness of this compound was not negatively impacted by resistance to bortezomib or carfilzomib.

Dual effects of duplex RNA harboring 5'-terminal triphosphate on gene silencing and RIG-I mediated innate immune response.

Duplex RNA harboring the 5'-terminal triphosphate RNA is hypothesized to not only execute selective gene silencing via RNA interference, but also induce type I interferon (IFN) through activation of the retinoic acid inducible gene I (RIG-I). We evaluated gene silencing efficacy of the shRNA containing 5'-triphosphate (3p-shRNA) targeting the hepatitis C virus (HCV) RNA genome in hepatic cells. Gene silencing efficacy of the 3p-shRNA was diminished due to the presence of the 5'-triphosphate moiety in shRNA, whereas the shRNA counterpart without 5'-triphosphate (HO-shRNA) showed a strong antiviral activity without significant induction of type I IFN in the cells. 3p-shRNA was observed to be a better activator of the RIG-I signaling than the HO-shRNA with an elevated induction of type I IFN in cells that express RIG-I. Taken together, we suggest that competition for the duplex RNA bearing 5'-triphosphate between RIG-I and RNA interference factors may compromise efficacy of selective gene silencing.

RNA aptamer-conjugated liposome as an efficient anticancer drug delivery vehicle targeting cancer cells in vivo.

To minimize the systemic toxicity prevalent to chemotherapeutics, we designed a novel anticancer drug-encapsulating liposome conjugated with an RNA aptamer specific to the prostate specific membrane antigen (PSMA), which is expressed on the surface of prostate cancer cells. The RNA aptamer-conjugated liposome, termed an aptamosome, was prepared by the post-insertion method, in which RNA aptamer-conjugated micelles were inserted into a liposome. These nanosized (90-100 nm) aptamer-conjugated liposomes specifically bind to LNCaP prostate epithelial cells that express PSMA and thus cause the nanoparticles to have significantly enhanced in vitro cellular binding and uptake as compared with nontargeted nanoparticles that lack the PSMA aptamer. Aptamosomes encapsulated with the anticancer drug doxorubicin (Dox) were significantly more toxic to the targeted LNCaP cells than to nontargeted cancer cells. Dox-encapsulating aptamosomes administered to LNCaP xenograft nude mice were selectively retained in tumor tissue. We also demonstrated in vivo anticancer efficacy of the Dox-encapsulating PSMA-aptamosomes on tumor size regression in LNCaP xenograft mice. We suggest that the encapsulation of toxic chemicals with aptamer-conjugated liposomes will enable the use of these bioconjugates in clinical practice with fewer side effects.