Tan et al. report that lymphatic dysfunction and immune cell infiltration contribute to mitral valve disease in a mouse model of Marfan syndrome. The cover art is an illustration highlighting the decreased density of lymphatic vessels (green) within the myxomatous degenerated mitral valve leaflets of a Marfan syndrome mouse model. Image generated using ChatGPT and edited in Adobe Fresco. Image credit: Can Tan.
The endocardium is a major source of coronary angiogenesis and arterialization, through coordinated cell fate transition and migration. However, the transcriptional regulatory network synchronizing cell fate determination and movement remains unclear. Here, we identified transcription factor HAND2 as a key candidate for coronary vascular formation. Endocardial deletion of Hand2 in mice disrupted arterial-venous networks and stunted coronary arteries, paralleling a ventricular noncompaction phenotype. Moreover, deletion of Hand2 produced excessive tip cells with defective movement. RNA-seq analysis revealed enhanced hypoxic metabolic activation but declined TGF-β/p38MAPK-dependent endothelial-to-mesenchymal transition (Endo-MT). In consistence, genetic inhibition of the core hypoxic regulators or pharmaceutical administration of TGFβ2 partially recovered the coronary arterial defects in Hand2 mutants. Furthermore, HAND2 was found directly bound to promoters of the target genes, harmonizing cell migration and cell fate transition. These findings pinpoint HAND2 as an essential regulator of the endocardial transcriptional regulatory network for coronary arterialization and provide potential therapeutic targets for coronary artery diseases.
Huijuan Wang, Haosheng Zhang, Leiyin Zheng, Peihan Zhang, Yuqian Wang, Sijia Ding, Wenping Liu, Yuanming Cheng, Zhongzhou Yang, Wen Luo
Polyendocrine metabolic ovarian syndrome (PMOS), formerly known as polycystic ovary syndrome (PCOS), is the most common endocrine disorder in women and is closely associated with complex diseases such as cardiovascular disease and type 2 diabetes. However, the mechanistic links between PMOS and its comorbidities remain poorly understood. Here, we present an integrative systems genetics platform that leverages genetic diversity in both mice and humans to dissect the drivers of PMOS and its associated complications. This framework uncovers conserved genetic and environmental factors underlying PMOS, identifies susceptible cell types and organs, and elucidates mechanisms linking PMOS to subsequent pathologies. For instance, we show that increased ovarian area contributes to both PMOS susceptibility and ovarian cancer progression, while specific ovary–heart signaling circuits modulate cardiac function with aging. We further identify ovarian SF3B1-mediated alternative splicing as a key mechanistic link between PMOS and metabolic traits. Pharmacologic inhibition of SF3B1 in mice reduced circulating testosterone, insulin and glucose levels, as well as fat mass expansion. Transcriptomics analysis of ovaries from mice and experiments using human cell lines localized these effects to exon skipping events in granulosa cells. Together, this study offers a mechanistic framework for modeling the diversity of PMOS pathologies and uncovers SF3B1-mediated splicing as a link between ovary function and systemic metabolism.
Christy M. Nguyen, Leandro M. Velez, Youngseo Cheon, Cimone L. Jackson, Casey D. Johnson, Ian Tamburini, Mingqi Zhou, Erik Alvstad, Isoo Yoon, Farheen Dustagheer, Marie Li, Tvisha Gujjarlapudi, Kaitlene Ofilan, Neha Mishra, Evan G. Williams, Danica Kwan, Carlos H. Viesi, Naveena Ujagar, David G. Ashbrook, Alistair Senior, Marin E. Nelson, Nicholas R. Pannunzio, Selma Masri, Evgeny Kvon, Grant MacGregor, Cholsoon Jang, Vittorio Sebastiano, Minji Byun, Changrui Xiao, Alexander S. Kauffman, Robert W. Williams, David E. James, Ivan Marazzi, Dequina Nicholas, Marcus Seldin
Hepatocellular carcinoma (HCC) is heterogeneous, and hepatocyte plasticity is linked to poorer patient outcomes. A subset of human HCC harboring Tuberous Sclerosis Complex 1 (TSC1) mutations exhibits more aggressive behavior. TFEB is a master regulator of lysosomal biogenesis and cell fate. We analyzed human normal and HCC tissue arrays for TFEB and CK19 expression, as well as bulk and single-cell RNA-seq datasets from mouse and human HCC, to define TFEB-associated transcriptional programs. We performed biochemical, histological, metabolomic, and transcriptomic analyses in liver-specific Tsc1 knockout (L-Tsc1 KO) and L-Tsc1,Tfeb double KO (DKO) mice. Loss of hepatic Tsc1 led to increased phosphorylation of S6 and 4EBP1, with paradoxical increases in TFEB nuclear translocation and activation. L-Tsc1 KO mice showed increased hepatocyte plasticity, decreased HFN4α, increased YAP1 activation, and spontaneous HCC with increased SOX9 and CK19-positive biliary epithelial cell (BEC)-like cells at 8-12 months. Deletion of Tfeb dampened hepatic metabolic reprogramming and hepatocyte fate changes and inhibited tumor progression in L-Tsc1 KO mice. Increased TFEB activity was associated with increased YAP and SOX9 gene expression and high-grade malignant HCC in humans. These findings indicate that loss of hepatic TSC1 leads to non-canonical TFEB activation, promoting hepatocyte plasticity and tumor heterogeneity associated with high-grade malignancy in both mouse and human HCC.
Chen Zhang, Xiaojuan Chao, Sha Neisha Williams, Xiaoli Wei, Anthony DiGirolamo, Alisha Bajracharya, Lichun Ma, Ming Huang, Nicholas Dunn, Wanqing Liu, Kaito Ueda, Masayuki Sugimoto, Andrea Ballabio, Hong-Min Ni, Wen-Xing Ding
Yashika Parashar, Zsofia Sztupinszki, Aurel György Prósz, Xiaolu Wang, Pratyusha Bala, Shweta Kiran Cavale, Chinedu Ukaegbu, Sapna Syngal, Asaf Maoz, Leah H. Biller, Ramona Lim, Matthew B. Yurgelun, Zoltan Szallasi, Nilay S. Sethi
Dietary cholesterol and de novo cholesterol synthesis in the liver use reciprocal coordination to maintain cholesterol homeostasis. However, high level of dietary cholesterol still promotes excessive cholesterol accumulation in the liver, leading to metabolic dysfunction-associated steatohepatitis (MASH), yet the mechanisms remain poorly understood. Here we show that hepatic S100A11, a member of the S100 family of calcium-binding proteins, positively responds to the dietary cholesterol level and is involved in hepatic cholesterol metabolism. S100A11 localizes to the endoplasmic reticulum and can bind to cholesterol. In vivo and in vitro, hepatic overexpression of S100A11 led to SREBP2 activation to promote cholesterol synthesis, uptake, and accumulation, consequently exacerbating steatohepatitis. In contrast, inactivation of S100A11 had opposite effects and improved steatohepatitis. Mechanistically, S100A11 triggers the non-canonical entry of SREBP2 into the nucleus through a S100A11-ANXA1-KPNB axis, distinct from the well-known INSIG-SCAP pathway or Caspase2 pathways. Therefore, our work identifies S100A11 as a regulator of liver cholesterol metabolism, providing a promising target to treat MASH and hypercholesterolemia.
Mingfeng Zhan, Xiumei Xu, Huiyin Wu, Qijing Fan, Hongsheng Lu, Chengbin Li, Linqiang Zhang, Tingting Zhu, Yunqian Shen, Jing Liu, Yaomei He, Yingjie Wu, Jingjing Zhang, Xiaoju Zou, Bin Liang
The cyclic GMP-AMP synthase (cGAS)–stimulator of interferon genes (STING) pathway is a key component of innate immunity, linking DNA detection to inflammatory and antiviral responses. Originally identified as a sensor for microbial DNA, cGAS is now understood to also respond to endogenous cytosolic DNA, and the pathway has been implicated in a wide range of physiological and pathological processes, including cancer, autoimmunity, neuroinflammation, and aging. This review series, organized by Dr. Alex Stegh, consolidates current knowledge and highlights emerging developments that may lead to therapeutic targeting of the cGAS-STING pathway across a range of disorders.
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