Browsing by Author "Li, Zhen"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Alcohol-induced gut microbial reorganization and associated overproduction of phenylacetylglutamine promotes cardiovascular disease
    (Springer Nature, 2024-12-30) Li, Zhen; Gu, Min; Zaparte, Aline; Fu, Xiaoming; Mahen, Kala; Mrdjen, Marko; Li, Xinmin S.; Yang, Zhihong; Ma, Jing; Thoudam, Themis; Chandler, Kristina; Hesler, Maggie; Heathers, Laura; Gorse, Kiersten; Van, Thanh Trung; Wong, David; Gibson, Aaron M.; Wang, Zeneng; Taylor, Christopher M.; Quijada, Pearl; Makarewich, Catherine A.; Hazen, Stanley L.; Liangpunsakul, Suthat; Brown, J. Mark; Lefer, David J.; Welsh, David A.; Sharp, Thomas E., III; Medicine, School of Medicine
    The mechanism(s) underlying gut microbial metabolite (GMM) contribution towards alcohol-mediated cardiovascular disease (CVD) is unknown. Herein we observe elevation in circulating phenylacetylglutamine (PAGln), a known CVD-associated GMM, in individuals living with alcohol use disorder. In a male murine binge-on-chronic alcohol model, we confirm gut microbial reorganization, elevation in PAGln levels, and the presence of cardiovascular pathophysiology. Fecal microbiota transplantation from pair-/alcohol-fed mice into naïve male mice demonstrates the transmissibility of PAGln production and the CVD phenotype. Independent of alcohol exposure, pharmacological-mediated increases in PAGln elicits direct cardiac and vascular dysfunction. PAGln induced hypercontractility and altered calcium cycling in isolated cardiomyocytes providing evidence of improper relaxation which corresponds to elevated filling pressures observed in vivo. Furthermore, PAGln directly induces vascular endothelial cell activation through induction of oxidative stress leading to endothelial cell dysfunction. We thus reveal that the alcohol-induced microbial reorganization and resultant GMM elevation, specifically PAGln, directly contributes to CVD.
  • Thumbnail Image
    Item
    SPOP Promotes Ubiquitination and Degradation of the ERG Oncoprotein to Suppress Prostate Cancer Progression
    (Elsevier, 2015-09-17) Gan, Wenjian; Dai, Xiangpeng; Lunardi, Andrea; Li, Zhen; Inuzuka, Hiroyuki; Liu, Pengda; Varmeh, Shoreh; Zhang, Jinfang; Cheng, Liang; Sun, Yin; Asara, John M.; Beck, Andrew H.; Huang, Jiaoti; Pandolfi, Pier Paolo; Wei, Wenyi; Department of Pathology and Laboratory Medicine, IU School of Medicine
    The ERG gene is fused to TMPRSS2 in approximately 50% of prostate cancers (PrCa), resulting in its overexpression. However, whether this is the sole mechanism underlying ERG elevation in PrCa is currently unclear. Here we report that ERG ubiquitination and degradation are governed by the Cullin 3-based ubiquitin ligase SPOP and that deficiency in this pathway leads to aberrant elevation of the ERG oncoprotein. Specifically, we find that truncated ERG (ΔERG), encoded by the ERG fusion gene, is stabilized by evading SPOP-mediated destruction, whereas prostate cancer-associated SPOP mutants are also deficient in promoting ERG ubiquitination. Furthermore, we show that the SPOP/ERG interaction is modulated by CKI-mediated phosphorylation. Importantly, we demonstrate that DNA damage drugs, topoisomerase inhibitors, can trigger CKI activation to restore the SPOP/ΔERG interaction and its consequent degradation. Therefore, SPOP functions as a tumor suppressor to negatively regulate the stability of the ERG oncoprotein in prostate cancer.