Park, E.-J. | Search bioRxiv

bioRxiv2020

Improvement of glymphatic-lymphatic drainage of beta-amyloid by focused ultrasound in Alzheimer's disease model

Drainage of parenchymal waste through the lymphatic system maintains brain homeostasis. Age-related changes of glymphatic-lymphatic clearance lead to the accumulation beta-amyloid (A{beta}) in dementia models. In this study, focused ultrasound treatment in combination with microbubbles (FUS-MB) improved A{beta} drainage in early dementia model mice, 5XFAD. FUS-MB enhanced solute A{beta} clearance from brain, but not plaques, to cerebrospinal fluid (CSF) space and then deep cervical lymph node (dCLN). dCLN ligation exaggerated memory impairment and progress of plaque formation and also the beneficial effects of FUS-MB upon A{beta} removal through CSF-lymphatic routes. In this ligation model, FUS-MB improved memory despite accumulation of A{beta} in CSF. In conclusion, FUS-MB enhances glymphatic-lymphatic clearance of A{beta} mainly by increasing brain-to-CSF A{beta} drainage. We suggest that FUS-MB can delay dementia progress in early period and benefits of FUS-MB depend on the effect of A{beta} disposal through CSF-lymphatics.

neuroscience↗

bioRxiv2019

Evidence for widespread selection in shaping the genomic landscape during speciation of Populus

Increasing our understanding of how various evolutionary processes drive the genomic landscape of variation is fundamental to a better understanding of the genomic consequences of speciation. However, the genome-wide patterns of within- and between-species variation have not been fully investigated in most forest tree species despite their global ecological and economic importance. Here, we use whole-genome resequencing data from four Populus species spanning the speciation continuum to reconstruct their demographic histories, investigate patterns of diversity and divergence, infer their genealogical relationships and estimate the extent of ancient introgression across the genome. Our results show substantial variation in these patterns along the genomes although this variation is not randomly distributed but is strongly predicted by the local recombination rates and the density of functional elements. This implies that the interaction between recurrent selection and intrinsic genomic features has dramatically sculpted the genomic landscape over long periods of time. In addition, our findings provide evidence that, apart from background selection, recent positive selection and long-term balancing selection are also crucial components in shaping patterns of genome-wide variation during the speciation process.

evolutionary biology↗