Biology subjects

Huang, H. Z.

Publications and source records attributed to Huang, H. Z..

3 recordsLinked to original sources

bioRxiv2023

Machine vision reveals micronucleus rupture as a potential driver of the transcriptomic response to aneuploidy

Recent advances in isolating cells based on visual phenotypes have transformed our ability to identify the mechanisms and consequences of complex traits. Micronucleus (MN) formation is a frequent outcome of genome instability, triggers extensive changes in genome structure and signaling coincident with MN rupture, and is almost exclusively defined by visual analysis. Automated MN detection in microscopy images has proved challenging, limiting discovery of the mechanisms and consequences of MN. In this study we describe two new MN segmentation modules: a rapid model for classifying micronucleated cells and their rupture status (VCS MN), and a robust model for accurate MN segmentation (MNFinder) from a broad range of cell lines. As proof-of-concept, we define the transcriptome of non-transformed human cells with intact or ruptured MN after chromosome missegregation by combining VCS MN with photoactivation-based cell isolation and RNASeq. Surprisingly, we find that neither MN formation nor rupture triggers a strong unique transcriptional response. Instead, transcriptional changes appear correlated with small increases in aneuploidy in these cell classes. Our MN segmentation modules overcome a significant challenge with reproducible MN quantification, and, joined with visual cell sorting, enable the application of powerful functional genomics assays to a wide-range of questions in MN biology.

cell biology↗

bioRxiv2021

Chromosome length and gene density contribute to micronuclear membrane stability

Micronuclei are derived from missegregated chromosomes and frequently lose membrane integrity, leading to DNA damage, innate immune activation, and metastatic signaling. Here we demonstrate that two characteristics of the trapped chromosome, length and gene density, are key contributors to micronuclei membrane stability in human cells. Chromosome length is proportional to micronuclei size, and gene density has an additive effect with micronucleus size on membrane stability. We demonstrate that these results are not due to chromosome-specific differences in spindle position or initial nuclear pore complex recruitment during post-mitotic nuclear envelope assembly. We find that chromosome length and micronuclei size strongly correlate with lamin B1 and nuclear pore density in intact micronuclei. Unexpectedly, lamin B1 levels do not predict nuclear lamina organization and membrane stability. Instead, small gene-dense micronuclei have decreased nuclear lamina gaps compared to large micronuclei, despite very low levels of lamin B1. Our data strongly suggest that nuclear envelope composition defects previously correlated with membrane rupture only partly explain membrane stability in micronuclei. We propose that an unknown factor linked to gene density has a separate function that inhibits the appearance of nuclear lamina gaps and delays membrane rupture until late in the cell cycle.

cell biology↗

bioRxiv2019

Protein kinase C is a key target for attenuation of Leigh syndrome by rapamycin

Leigh syndrome is a fatal neurometabolic disorder caused by defects in mitochondrial function. mTOR inhibition with rapamycin attenuates disease progression in a mouse model of Leigh syndrome (Ndufs4 KO mouse); however, the mechanism of rescue is unknown. Here we assessed the impact of rapamycin on the brain proteome and phosphoproteome of Ndufs4 KO mice. We report that rapamycin remodels the brain proteome to alter mitochondrial structure, inhibits signaling through both mTOR complexes, and inhibits multiple protein kinase C (PKC) isoforms. Administration of PKC inhibitors was sufficient to increase survival, delay neurological deficits, and prevent hair loss in Ndufs4 KO mice. Thus, PKC may be a viable therapeutic target for treating severe mitochondrial disease. One Sentence SummaryProteomic and phosphoproteomic analysis of mouse brain identifies PKC as a key target to treat mitochondrial disease

neuroscience↗