Bulk RNA-seq and scRNA-seq analysis reveal an activation of immune response and compromise of secretory function in major salivary glands of obese mice

A UTP3-dependent nucleolar translocation pathway facilitates pre-rRNA 5'ETS processing

The ribosome small subunit (SSU) is assembled by the SSU processome which contains approximately 70 non-ribosomal protein factors. Whilst the biochemical mechanisms of the SSU processome in 18S rRNA processing and maturation have been extensively studied, how SSU processome components enter the nucleolus has yet to be systematically investigated. Here, in examining the nucleolar localization of 50 human SSU processome components, we found that UTP3, together with another 24 proteins, enter the nucleolus autonomously. For the remaining 25 proteins we found that UTP3/SAS10 assists the nucleolar localization of five proteins (MPP10, UTP25, EMG1 and the two UTP-B components UTP12 and UTP13), likely through its interaction with nuclear importin α. This 'ferrying' function of UTP3 was then confirmed as conserved in the zebrafish. We also found that knockdown of human UTP3 impairs cleavage at the A0-site while loss-of-function of either utp3/sas10 or utp13/tbl3 in zebrafish causes the accumulation of aberrantly processed 5'ETS products, which highlights the crucial role of UTP3 in mediating 5'ETS processing. Mechanistically, we found that UTP3 facilitates the degradation of processed 5'ETS by recruiting the RNA exosome component EXOSC10 to the nucleolus. These findings lay the groundwork for studying the mechanism of cytoplasm-to-nucleolus trafficking of SSU processome components.

Effect of adiposity status on salivary Streptococcus mutans and Streptococcus sobrinus

OBJECTIVES

To investigate the effect of adiposity status, salivary physicochemical parameters, and inflammatory biomarkers on the salivary abundance of the two main cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus among Hong Kong adolescents.

SUBJECTS AND METHODS

This study included 180 adolescents aged 12-15 years from Hong Kong local secondary schools. Anthropometric measurements and oral health examinations were performed. Saliva samples were collected to measure salivary physicochemical parameters, protein biomarker levels, and salivary abundance of Streptococcus mutans, Streptococcus sobrinus, and total bacteria.

RESULTS

Adolescents with general overweight/obesity or central obesity had significantly higher salivary Streptococcus mutans abundance and total bacterial load, lower stimulated salivary flow rate, and lower secretory phospholipase A2 group IIA levels than the lean controls. Adolescents with general overweight/obesity (OR = 3.33; 95% CI: 1.28-8.65) and those with central obesity (OR = 2.47; 95% CI: 1.02-6.00) had a significantly higher chance of having high salivary abundance of Streptococcus mutans than the lean controls after adjusting for confounders, with a similar detection rate of salivary Streptococcus sobrinus.

CONCLUSION

General overweight or obesity and central obesity were associated with a high salivary abundance of Streptococcus mutans but had no significant effect on salivary Streptococcus sobrinus.

Insect Insights at the Single-Cell Level: Technologies and Applications

Single-cell techniques are a promising way to unravel the complexity and heterogeneity of transcripts at the cellular level and to reveal the composition of different cell types and functions in a tissue or organ. In recent years, advances in single-cell RNA sequencing (scRNA-seq) have further changed our view of biological systems. The application of scRNA-seq in insects enables the comprehensive characterization of both common and rare cell types and cell states, the discovery of new cell types, and revealing how cell types relate to each other. The recent application of scRNA-seq techniques to insect tissues has led to a number of exciting discoveries. Here we provide an overview of scRNA-seq and its application in insect research, focusing on biological applications, current challenges, and future opportunities to make new discoveries with scRNA-seq in insects.