Genomic origin, fragmentomics, and transcriptional properties of long cell-free DNA molecules in human plasma

Recent studies have revealed an unexplored population of long cell-free DNA (cfDNA) molecules in human plasma using long-read sequencing technologies. However, the biological properties of long cfDNA molecules (>500 bp) remain largely unknown. To this end, we have investigated the origins of long cfDNA molecules from different genomic elements. Analysis of plasma cfDNA using long-read sequencing reveals an uneven distribution of long molecules from across the genome. Long cfDNA molecules show overrepresentation in euchromatic regions of the genome, in sharp contrast to short DNA molecules. We observe a stronger relationship between the abundance of long molecules and mRNA gene expression levels, compared with short molecules (Pearson's r = 0.71 vs. -0.14). Moreover, long and short molecules show distinct fragmentation patterns surrounding CpG sites. Leveraging the cleavage preferences surrounding CpG sites, the combined cleavage ratios of long and short molecules can differentiate patients with hepatocellular carcinoma (HCC) from non-HCC subjects (AUC = 0.87). We also investigated knockout mice in which selected nuclease genes had been inactivated in comparison with wild-type mice. The proportion of long molecules originating from transcription start sites are lower in Dffb-deficient mice but higher in Dnase1l3-deficient mice compared with that of wild-type mice. This work thus provides new insights into the biological properties and potential clinical applications of long cfDNA molecules.

Efficient Killing of Multidrug-Resistant Internalized Bacteria by AIEgens In Vivo

Bacteria infected cells acting as "Trojan horses" not only protect bacteria from antibiotic therapies and immune clearance, but also increase the dissemination of pathogens from the initial sites of infection. Antibiotics are hard and insufficient to treat such hidden internalized bacteria, especially multidrug-resistant (MDR) bacteria. Herein, aggregation-induced emission luminogens (AIEgens) such as N,N-diphenyl-4-(7-(pyridin-4-yl) benzo [c] [1,2,5] thiadiazol-4-yl) aniline functionalized with 1-bromoethane (TBP-1) and (3-bromopropyl) trimethylammonium bromide (TBP-2) (TBPs) show potent broad-spectrum bactericidal activity against both extracellular and internalized Gram-positive pathogens. TBPs trigger reactive oxygen species (ROS)-mediated membrane damage to kill bacteria, regardless of light irradiation. TBPs effectively kill bacteria without the development of resistance. Additionally, such AIEgens activate mitochondria dependent autophagy to eliminate internalized bacteria in host cells. Compared to the routinely used vancomycin in clinic, TBPs demonstrate comparable efficacy against methicillin-resistant Staphylococcus aureus (MRSA) in vivo. The studies suggest that AIEgens are promising new agents for the treatment of MDR bacteria associated infections.

Clusteroluminescence from Cluster Excitons in Small Heterocyclics Free of Aromatic Rings

The study of nonconventional luminescence is important for revealing the luminescence of natural systems and has gradually drawn the attention of researchers in recent years. However, the underlying mechanism is still inexplicable. Herein, the luminescence behavior of two series of simple, heteroatom-containing small molecules without aromatic rings, i.e., maleimide and succinimide derivatives, are studied to gain further mechanistic insight into the nonconventional luminescence process. It has been unveiled that all the molecules exhibit bright and visible luminescence in concentrated solution and solid state and the formation of clusters is the root cause for such behaviors, which can effectively increase the possibility of both the nonradiative n-π* and favorable π-π* transitions and stabilize the excitons formed in the excited state. The distinctive luminescent phenomena and intriguing mechanism presented in this work will be significant for understanding the mechanism of clusteroluminescence and provide new strategies for the rational design of novel luminescent materials.

Genetic and polygenic risk score analysis for Alzheimer's disease in the Chinese population

INTRODUCTION

Dozens of Alzheimer's disease (AD)-associated loci have been identified in European-descent populations, but their effects have not been thoroughly investigated in the Hong Kong Chinese population.

METHODS

TaqMan array genotyping was performed for known AD-associated variants in a Hong Kong Chinese cohort. Regression analysis was conducted to study the associations of variants with AD-associated traits and biomarkers. Lasso regression was applied to establish a polygenic risk score (PRS) model for AD risk prediction.

RESULTS

SORL1 is associated with AD in the Hong Kong Chinese population. Meta-analysis corroborates the AD-protective effect of the SORL1 rs11218343 C allele. The PRS is developed and associated with AD risk, cognitive status, and AD-related endophenotypes. TREM2 H157Y might influence the amyloid beta 42/40 ratio and levels of immune-associated proteins in plasma.

DISCUSSION

SORL1 is associated with AD in the Hong Kong Chinese population. The PRS model can predict AD risk and cognitive status in this population.