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Biology subjects

Yuan, A. H.

Publications and source records attributed to Yuan, A. H..

2 recordsLinked to original sources

Intercellular Signaling Pathways as Therapeutic Targets for Vascular Dementia Repair

Vascular dementia (VaD) is a white matter ischemic disease and the second-leading cause of dementia, with no direct therapy. Within the lesion site, cell-cell interactions dictate the trajectory towards disease progression or repair. To elucidate the underlying intercellular signaling pathways, a VaD mouse model was developed for transcriptomic and functional studies. The mouse VaD transcriptome was integrated with a human VaD snRNA-Seq dataset. A custom-made database encompassing 4053 human and 2032 mouse ligand-receptor (L-R) interactions identified significantly altered pathways shared between human and mouse VaD. Two intercellular L-R systems, Serpine2-Lrp1 and CD39-A3AR, were selected for mechanistic study as both the ligand and receptor were dysregulated in VaD. Decreased Seprine2 expression enhances OPC differentiation in VaD repair. A clinically relevant drug that reverses the loss of CD39-A3AR function promotes tissue and behavioral recovery in the VaD model. This study presents novel intercellular signaling targets and may open new avenues for VaD therapies.

neuroscience↗

A simple mechanism for epigenetic inheritance of silent chromatin.

Mechanisms enabling genetically identical cells to differentially regulate gene expression are complex and central to organismal development and evolution. While gene silencing pathways involving sequence-specific recruitment of histone-modifying enzymes are prevalent in nature, examples of sequence-independent heritable gene silencing are scarce. Studies of Schizosaccharomyces pombe indicate that sequence-independent propagation of heterochromatin can occur but requires numerous multisubunit protein complexes and their various activities. Such complexity has precluded a coherent articulation of the minimal requirements for heritable gene silencing by conventional approaches. Here, we take an unconventional approach to defining these requirements by engineering sequence-independent silent chromatin inheritance in Saccharomyces cerevisiae. The memory-conferring mechanism is remarkably simple and requires only two proteins, one that recognizes histone H3 methylation and deacetylates histone H4, and another that recognizes unmodified H4 and catalyzes H3 methylation. These bilingual "read-write" proteins form an interdependent positive feedback loop capable of transmitting sequence-independent silent information over multiple generations.

molecular biology↗