Remodelling of whole-body lipid metabolism and a diabetic-like phenotype caused by loss of CDK1 and hepatocyte division
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore
- National University of Singapore (NUS), Singapore
- Singapore Bioimaging Consortium, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
- National University of Singapore NUS), Singapore
- Lund University, Sweden
Abstract
Cell cycle progression and lipid metabolism are well-coordinated processes required for proper cell proliferation. In liver diseases that arise from dysregulated lipid metabolism, proliferation is diminished. To study the outcome of CDK1 loss and blocked hepatocyte proliferation on lipid metabolism and the consequent impact on whole-body physiology, we performed lipidomics, metabolomics, and RNA-seq analyses on a mouse model. We observed reduced triacylglycerides in liver of young mice, caused by oxidative stress that activated FOXO1 to promote expression of ATGL. Additionally, we discovered that hepatocytes displayed malfunctioning b-oxidation, reflected by increased acylcarnitines and reduced b-hydroxybutyrate. This led to elevated plasma free fatty acids, which were transported to the adipose tissue for storage and triggered greater insulin secretion. Upon aging, chronic hyperinsulinemia resulted in insulin resistance and hepatic steatosis through activation of LXR. Here we demonstrate that loss of hepatocyte proliferation is not only an outcome but possibly causative for liver pathology.
Data availability
Raw sequencing data is available at NCBI GEO under accession number GSE159498.
Article and author information
Author details
Funding
The work was supported in part by the Faculty of Medicine, Lund University to PK, the Biomedical Research Council, Agency for Science, Technology and Research (A*STAR) to PK and to AC-G and MRW (IAF-ICP I1901E0040); by SINGA (Singapore International Graduate Award) to GZ; by the National Medical Research Council Singapore, NMRC (NMRC/CBRG/0091/2015) to PK; by National Research Foundation Singapore grant (NRF2016-CRP001-103) to PK; by the National Medical Research Council of Singapore (NMRC-CG-M009 to H.C.); by grants from the National University of Singapore via the Life Sciences Institute to JCF; the Swedish Foundation for Strategic Research Dnr IRC15-0067; and Swedish Research Council, Strategic Research Area EXODIAB, Dnr 2009-1039. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal experiments were performed in accordance to protocols (#171268) approved by the A*STAR Institutional Animal Care and Use Committee (IACUC) based on the National Advisory Committee for Laboratory Animal Research (NACLAR) Guidelines.
Copyright
© 2020, Ow et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Remodelling of whole-body lipid metabolism and a diabetic-like phenotype caused by loss of CDK1 and hepatocyte division
eLife 9:e63835.
https://doi.org/10.7554/eLife.63835
Further reading
-
- Cell Biology
Centrioles have a unique, conserved architecture formed by three linked, ‘triplet’, microtubules arranged in ninefold symmetry. The mechanisms by which these triplet microtubules are formed remain unclear but likely involve the noncanonical tubulins delta-tubulin and epsilon-tubulin. Previously, we found that human cells lacking delta-tubulin or epsilon-tubulin form abnormal centrioles, characterized by an absence of triplet microtubules, lack of central core protein POC5, and a futile cycle of centriole formation and disintegration (Wang et al., 2017). Here, we show that human cells lacking either TEDC1 or TEDC2 have similar abnormalities. Using ultrastructure expansion microscopy, we observed that mutant centrioles elongate to the same length as control centrioles in G2 phase and fail to recruit central core scaffold proteins. Remarkably, mutant centrioles also have an expanded proximal region. During mitosis, these mutant centrioles further elongate before fragmenting and disintegrating. All four proteins physically interact and TEDC1 and TEDC2 can form a subcomplex in the absence of the tubulins, supporting an AlphaFold Multimer model of the tetramer. TEDC1 and TEDC2 localize to centrosomes and are mutually dependent on each other and on delta-tubulin and epsilon-tubulin for localization. Our results demonstrate that delta-tubulin, epsilon-tubulin, TEDC1, and TEDC2 function together to promote robust centriole architecture, laying the foundation for future studies on the mechanisms underlying the assembly of triplet microtubules and their interactions with centriole structure.
-
- Cancer Biology
- Cell Biology
The most common primary malignancy of the liver, hepatocellular carcinoma (HCC), is a heterogeneous tumor entity with high metastatic potential and complex pathophysiology. Increasing evidence suggests that tissue mechanics plays a critical role in tumor onset and progression. Here, we show that plectin, a major cytoskeletal crosslinker protein, plays a crucial role in mechanical homeostasis and mechanosensitive oncogenic signaling that drives hepatocarcinogenesis. Our expression analyses revealed elevated plectin levels in liver tumors, which correlated with poor prognosis for HCC patients. Using autochthonous and orthotopic mouse models we demonstrated that genetic and pharmacological inactivation of plectin potently suppressed the initiation and growth of HCC. Moreover, plectin targeting potently inhibited the invasion potential of human HCC cells and reduced their metastatic outgrowth in the lung. Proteomic and phosphoproteomic profiling linked plectin-dependent disruption of cytoskeletal networks to attenuation of oncogenic FAK, MAPK/Erk, and PI3K/Akt signatures. Importantly, by combining cell line-based and murine HCC models, we show that plectin inhibitor plecstatin-1 (PST) is well-tolerated and potently inhibits HCC progression. In conclusion, our study demonstrates that plectin-controlled cytoarchitecture is a key determinant of HCC development and suggests that pharmacologically induced disruption of mechanical homeostasis may represent a new therapeutic strategy for HCC treatment.
