Cell cycle regulation is largely abnormal in cancers. Molecular understanding and therapeutic targeting of the aberrant cell cycle are essentially meaningful. Here, we identified an under-appreciated Serine/Threonine kinase, CDKL3 (Cyclin-dependent kinase like 3), crucially drives the rapid cell cycle progression and cell growth in cancers. Mechanism-wise, CDKL3 localizes in the nucleus and associates with specific cyclin to directly phosphorylate Retinoblastoma (Rb) for quiescence exit. In parallel, CDKL3 prevents the ubiquitin-proteasomal degradation of CDK4 by direct phosphorylation on T172 to sustain G1 phase advancement. The crucial function of CDKL3 in cancers was demonstrated both in vitro and in vivo. We also designed, synthesized and characterized a first-in-class CDKL3-specific inhibitor, HZ1. HZ1 exhibits greater potency than CDK4/6 (Cyclin-dependent kinase 4/6) inhibitor in pan-cancer treatment by causing cell cycle arrest and overcomes the acquired resistance of the latter. In particular, CDKL3 has significant clinical relevance in colon cancer, and the effectiveness of HZ1 was demonstrated by murine and patient-derived cancer models. Collectively, this work presented an integrated paradigm of cancer cell cycle regulation and suggested CDKL3-targeting as a feasible approach in cancer treatment.
Haijiao Zhang, Jiahui Lin, Shaoqin Zheng, Lanjing Ma, Zhongqiu Pang, Hongyi Yin, Chengcheng Meng, Yinuo Wang, Qing Han, Xi Zhang, Zexu Li, Liu Cao, Lijun Liu, Teng Fei, Daming Gao, Liang Yang, Xueqiang Peng, Chen Ding, Shixue Wang, Ren Sheng
Mitochondria-related neurodegenerative diseases have been implicated in the disruption of primary cilia function. Mutation in an intrinsic mitochondrial complex I component NDUFAF2 has been identified in Leigh syndrome, a severe inherited mitochondriopathy. Mutations in ARMC9, which encodes a basal body protein, cause Joubert syndrome, a ciliopathy with defects in the brain, kidney, and eye. Here, we report a mechanistic link between mitochondria metabolism and primary cilia signaling. We discovered that loss of NDUFAF2 caused both mitochondrial and ciliary defects in vitro and in vivo and identified NDUFAF2 as a binding partner for ARMC9. We also found that NDUFAF2 was both necessary and sufficient for cilia formation and that exogenous expression of NDUFAF2 rescued the ciliary and mitochondrial defects observed in cells from patients with known ARMC9 deficiency. NAD+ supplementation restored mitochondrial and ciliary dysfunction in ARMC9-deficient cells and zebrafish and ameliorated the ocular motility and motor deficits of a patient with ARMC9 deficiency. The present results provide a compelling mechanistic link, supported by evidence from human studies, between primary cilia and mitochondrial signaling. Importantly, our findings have significant implications for the development of therapeutic approaches targeting ciliopathies.
Chien-Hui Lo, Zhiquan Liu, Siyu Chen, Frank Lin, Andrew R. Berneshawi, Charles Q. Yu, Euna B. Koo, Tia J. Kowal, Ke Ning, Yang Hu, Won-Jing Wang, Y. Joyce Liao, Yang Sun
Healthy adipose tissue is essential for normal physiology. There are 2 broad types of adipose tissue depots: brown adipose tissue (BAT), which contains adipocytes poised to burn energy through thermogenesis, and white adipose tissue (WAT), which contains adipocytes that store lipids. However, within those types of adipose, adipocytes possess depot and cell-specific properties that have important implications. For example, the subcutaneous and visceral WAT confers divergent risk for metabolic disease. Further, within a depot, different adipocytes can have distinct properties; subcutaneous WAT can contain adipocytes with either white or brown-like (beige) adipocyte properties. However, the pathways that regulate and maintain this cell and depot-specificity are incompletely understood. Here, we found that the transcription factor KLF15 is required for maintaining white adipocyte properties selectively within the subcutaneous WAT. We revealed that deletion of Klf15 is sufficient to induce beige adipocyte properties and that KLF15’s direct regulation of Adrb1 is a critical molecular mechanism for this process. We uncovered that this activity is cell autonomous but has systemic implications in mouse models and is conserved in primary human adipose cells. Our results elucidate a pathway for depot-specific maintenance of white adipocyte properties that could enable the development of therapies for obesity and associated diseases.
Liang Li, Brian J. Feldman
Ubiquitination plays an essential role in protein stability, subcellular localization, and interactions. Crosstalk between different types of ubiquitination results in distinct biological outcomes for proteins. However, the role of ubiquitination-related crosstalk in lymph node (LN) metastasis and the key regulatory factors controlling this process have not been determined. Using high-throughput sequencing, we found that ubiquitin-conjugating enzyme E2 C (UBE2C) was overexpressed in bladder cancer (BCa) and was strongly associated with an unfavorable prognosis. Overexpression of UBE2C increased BCa lymphangiogenesis and promoted LN metastasis both in vitro and in vivo. Mechanistically, UBE2C mediated sodium-coupled neutral amino acid transporter 2 (SNAT2) monoubiquitination at lysine 59 to inhibit K63-linked polyubiquitination at lysine 33 of SNAT2. Crosstalk between monoubiquitination and K63-linked polyubiquitination increased SNAT2 membrane protein levels by suppressing epsin 1–mediated (EPN1-mediated) endocytosis. SNAT2 facilitated glutamine uptake and metabolism to promote VEGFC secretion, ultimately leading to lymphangiogenesis and LN metastasis in patients with BCa. Importantly, inhibition of UBE2C significantly attenuated BCa lymphangiogenesis in a patient-derived xenograft model. Our results reveal the mechanism by which UBE2C mediates crosstalk between the monoubiquitination and K63-linked polyubiquitination of SNAT2 to promote BCa metastasis and identify UBE2C as a promising target for treating LN-metastatic BCa.
Wenjie Li, Changhao Chen, Hanhao Zheng, Yan Lin, Mingjie An, Daiyin Liu, Yonghai Zhang, Mingchao Gao, Tianhang Lan, Wang He
Clear cell renal cell carcinoma (ccRCC) is an aggressive cancer driven by VHL loss and aberrant HIF-2α signaling. Identifying means to regulate HIF-2α thus has potential therapeutic benefit. Acetyl-CoA synthetase 2 (ACSS2) converts acetate to acetyl-CoA and is associated with poor patient prognosis in ccRCC. Here we tested the effects of ACSS2 on HIF-2α and cancer cell metabolism and growth in ccRCC models and clinical samples. ACSS2 inhibition reduced HIF-2α levels and suppressed ccRCC cell line growth in vitro, in vivo, and in cultures of primary ccRCC patient tumors. This treatment reduced glycolytic signaling, cholesterol metabolism, and mitochondrial integrity, all of which are consistent with loss of HIF-2α. Mechanistically, ACSS2 inhibition decreased chromatin accessibility and HIF-2α expression and stability. While HIF-2α protein levels are widely regulated through pVHL-dependent proteolytic degradation, we identify a potential pVHL-independent pathway of degradation via the E3 ligase MUL1. We show that MUL1 can directly interact with HIF-2α and that overexpression of MUL1 decreased HIF-2α levels in a manner partially dependent on ACSS2. These findings identify multiple mechanisms to regulate HIF-2α stability and ACSS2 inhibition as a strategy to complement HIF-2α–targeted therapies and deplete pathogenically stabilized HIF-2α.
Zachary A. Bacigalupa, Emily N. Arner, Logan M. Vlach, Melissa M. Wolf, Whitney A. Brown, Evan S. Krystofiak, Xiang Ye, Rachel A. Hongo, Madelyn Landis, Edith K. Amason, Kathryn E. Beckermann, W. Kimryn Rathmell, Jeffrey C. Rathmell
GNAO1 mutated in pediatric encephalopathies encodes the major neuronal G-protein Gαo. Of >80 pathogenic mutations, most are single amino acid substitutions spreading across Gαo sequence. We perform extensive characterization of Gαo mutants showing abnormal GTP uptake and hydrolysis, and deficiencies to bind Gβγ and RGS19. Plasma membrane localization of Gαo is decreased for a subset of mutations that leads to epilepsy; dominant interactions with GPCRs also emerge for the more severe mutants. Pathogenic mutants massively gain interaction with Ric8A and, surprisingly, Ric8B proteins, delocalizing them from cytoplasm to Golgi. Of these two mandatory Gα-subunit chaperones, Ric8A is normally responsible for the Gαi/o, Gαq, and Gα12/13 subfamilies, and Ric8B solely for Gαs/olf. Ric8A/B mediate the disease dominance when engaging in neomorphic interactions with pathogenic Gαo through disbalancing the neuronal G protein signaling networks. As the strength of Gαo-Ric8B interactions correlates with disease severity, our study further identifies an efficient biomarker and predictor for clinical manifestations in GNAO1 encephalopathies. Our work discovers the neomorphic molecular mechanism of mutations underlying pediatric encephalopathies and offers insights to other maladies caused by G protein misfunctioning and further genetic diseases.
Gonzalo P. Solis, Alexey Koval, Jana Valnohova, Arghavan Kazemzadeh, Mikhail Savitsky, Vladimir L. Katanaev
The identification of genes that confer either extension of lifespan or accelerate age-related decline was a step forward in understanding the mechanisms of ageing and revealed that it is partially controlled by genetics and transcriptional programs. Here we discovered that the human DNA sequence C16ORF70 encoded for a protein, named MYTHO (Macroautophagy and YouTH Optimizer), which controls life- and health-span. MYTHO protein is conserved from C. elegans to humans and its mRNA was upregulated in aged mice and elderly people. Deletion of the ortholog myt-1 gene in C. elegans dramatically shortened lifespan and decreased animal survival upon exposure to oxidative stress. Mechanistically, MYTHO is required for autophagy likely because it acts as a scaffold that binds WIPI2 and BCAS3 to recruit and assemble the conjugation system at the phagophore, the nascent autophagosome. We conclude that MYTHO is a transcriptionally regulated initiator of autophagy that is central in promoting stress resistance and healthy ageing.
Anais Franco-Romero, Valeria Morbidoni, Giulia Milan, Roberta Sartori, Jesper Wulff, Vanina Romanello, Andrea Armani, Leonardo Salviati, Maria Conte, Stefano Salvioli, Claudio Franceschi, Viviana Buonomo, Casey O. Swoboda, Paolo Grumati, Luca Pannone, Simone Martinelli, Harold B.J. Jefferies, Ivan Dikic, Jennifer van der Laan, Filipe Cabreiro, Douglas P. Millay, Sharon A. Tooze, Eva Trevisson, Marco Sandri
Endothelial cells (ECs) in the descending aorta are exposed to high laminar shear stress, and this supports an anti-inflammatory phenotype. High laminar shear stress also induces flow-aligned cell elongation and front-rear polarity, but whether these are required for the anti-inflammatory phenotype is unclear. Here, we showed that Caveolin-1-rich microdomains polarize to the downstream end of ECs that are exposed to continuous high laminar flow. These microdomains were characterized by high membrane rigidity, filamentous actin (F-actin), and raft-associated lipids. Transient receptor potential vanilloid-type 4 (TRPV4) ion channels were ubiquitously expressed on the plasma membrane but mediated localized Ca2+ entry only at these microdomains where they physically interacted with clustered Caveolin-1. These focal Ca2+ bursts activated endothelial nitric oxide synthase (eNOS) within the confines of these domains. Importantly, we found that signaling at these domains required both cell body elongation and sustained flow. Finally, TRPV4 signaling at these domains was necessary and sufficient to suppress inflammatory gene expression, and exogenous activation of TRPV4 channels ameliorated the inflammatory response to stimuli both in vitro and in vivo. Our work revealed a polarized mechanosensitive signaling hub in arterial ECs that dampens inflammatory gene expression and promotes cell resilience.
Soon-Gook Hong, Julianne W. Ashby, John P. Kennelly, Meigan Wu, Michelle Steel, Eesha Chattopadhyay, Rob Foreman, Peter Tontonoz, Elizabeth J. Tarling, Patric Turowski, Marcus Gallagher-Jones, Julia J. Mack
Recently developed anti-migraine therapeutics targeting calcitonin gene-related peptide (CGRP) signaling are effective, though their sites of activity remain elusive. Notably, the lymphatic vasculature is responsive to CGRP signaling, but whether meningeal lymphatic vessels (MLVs) contribute to migraine pathophysiology is unknown. Mice with lymphatic vasculature deficient in the CGRP receptor (CalcrliLEC mice) treated with nitroglycerin (NTG)-mediated chronic migraine exhibit reduced pain and light avoidance compared to NTG-treated littermate controls. Gene expression profiles of lymphatic endothelial cells (LECs) isolated from the meninges of Rpl22HA/+;Lyve1Cre RiboTag mice treated with NTG revealed increased MLV-immune interactions compared to cells from untreated mice. Interestingly, the relative abundance of mucosal vascular addressin cell adhesion molecule 1 (MAdCAM1)-interacting CD4+ T cells was increased in the deep cervical lymph nodes of NTG-treated control mice but not in NTG-treated CalcrliLEC mice. Treatment of cultured hLECs with CGRP peptide in vitro induced vascular endothelial (VE)-cadherin rearrangement and reduced functional permeability. Likewise, intra cisterna magna injection of CGRP caused rearrangement of VE-Cadherin, decreased MLV uptake of cerebrospinal fluid (CSF), and impaired CSF drainage in control mice, but not in CalcrliLEC mice. Collectively, these findings reveal a previously unrecognized role for lymphatics in chronic migraine, whereby CGRP signaling primes MLVs-immune interactions and reduces CSF efflux.
Nathan P. Nelson-Maney, Laszlo Balint, Anna L.S. Beeson, D. Stephen Serafin, Bryan M. Kistner, Elizabeth S. Douglas, Aisha H. Siddiqui, Alyssa M. Tauro, Kathleen M. Caron
Emma L. Robinson, Charles A. Tharp, Rushita A. Bagchi, Timothy A. McKinsey
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