Viral Shedding in Mice following Intravenous Adenovirus Injection: Impact on Biosafety Classification

Quercetin modulates expression of serum exosomal long noncoding RNA NEAT1 to regulate the miR-129-5p/BDNF axis and attenuate cognitive impairment in diabetic mice

AIMS

Cognitive impairment poses a considerable health challenge in the context of type 2 diabetes mellitus (T2DM), emphasizing the need for effective interventions. This study delves into the therapeutic efficacy of quercetin, a natural flavonoid, in mitigating cognitive impairment induced by T2DM in murine models.

MATERIALS AND METHODS

Serum exosome samples were obtained from both T2DM-related and healthy mice for transcriptome sequencing, enabling the identification of differentially expressed mRNAs and long noncoding RNAs (lncRNAs). Subsequent experiments were conducted to ascertain the binding affinity between mmu-miR-129-5p, NEAT1 and BDNF. The structural characteristics and dimensions of isolated exosomes were scrutinized, and the expression levels of exosome-associated proteins were quantified. Primary mouse hippocampal neurons were cultured for in vitro validation, assessing the expression of pertinent genes as well as neuronal vitality, proliferation, and apoptosis capabilities. For in vivo validation, a T2DM mouse model was established, and quercetin treatment was administered. Changes in various parameters, cognitive ability, and the expression of insulin-related proteins, along with pivotal signaling pathways, were monitored.

KEY FINDINGS

Analysis of serum exosomes from T2DM mice revealed dysregulation of NEAT1, mmu-miR-129-5p, and BDNF. In vitro investigations demonstrated that NEAT1 upregulated BDNF expression by inhibiting mmu-miR-129-5p. Overexpression of mmu-miR-129-5p or silencing NEAT1 resulted in the downregulation of insulin-related protein expression, enhanced apoptosis, and suppressed neuronal proliferation. In vivo studies validated that quercetin treatment significantly ameliorated T2DM-related cognitive impairment in mice.

SIGNIFICANCE

These findings suggest that quercetin holds promise in inhibiting hippocampal neuron apoptosis and improving T2DM-related cognitive impairment by modulating the NEAT1/miR-129-5p/BDNF pathway within serum exosomes.

Comparison of de novo assembly using long-read shotgun metagenomic sequencing of viruses in fecal and serum samples from marine mammals

Introduction

Viral diseases of marine mammals are difficult to study, and this has led to a limited knowledge on emerging known and unknown viruses which are ongoing threats to animal health. Viruses are the leading cause of infectious disease-induced mass mortality events among marine mammals.

Methods

In this study, we performed viral metagenomics in stool and serum samples from California sea lions (Zalophus californianus) and bottlenose dolphins (Tursiops truncates) using long-read nanopore sequencing. Two widely used long-read de novo assemblers, Canu and Metaflye, were evaluated to assemble viral metagenomic sequencing reads from marine mammals.

Results

Both Metaflye and Canu assembled similar viral contigs of vertebrates, such as Parvoviridae, and Poxviridae. Metaflye assembled viral contigs that aligned with one viral family that was not reproduced by Canu, while Canu assembled viral contigs that aligned with seven viral families that was not reproduced by Metaflye. Only Canu assembled viral contigs from dolphin and sea lion fecal samples that matched both protein and nucleotide RefSeq viral databases using BLASTx and BLASTn for Anelloviridae, Parvoviridae and Circoviridae families. Viral contigs assembled with Canu aligned with torque teno viruses and anelloviruses from vertebrate hosts. Viruses associated with invertebrate hosts including densoviruses, Ambidensovirus, and various Circoviridae isolates were also aligned. Some of the invertebrate and vertebrate viruses reported here are known to potentially cause mortality events and/or disease in different seals, sea stars, fish, and bivalve species.

Discussion

Canu performed better by producing the most viral contigs as compared to Metaflye with assemblies aligning to both protein and nucleotide databases. This study suggests that marine mammals can be used as important sentinels to surveil marine viruses that can potentially cause diseases in vertebrate and invertebrate hosts.