Cell biology
Abstract
Idiopathic pulmonary fibrosis (IPF) is a devastating chronic lung disorder with limited treatment options. Macropinocytosis is one of the key cellular processes involved in nutrient consumption from the extracellular environment under stress conditions. Here, we studied the role of macropinocytosis in experimental pulmonary fibrosis models. We found that macropinocytosis is increased in human lung fibroblasts (HLFs) derived from IPF patients. The inhibition of macropinocytosis with 5-(n-ethyl-n-isopropyl)-amiloride (EIPA) inhibited profibrotic responses in IPF-derived and TGF-1-stimulated HLFs and reduced pulmonary fibrosis in bleomycin (Bleo)-injured mice. EIPA exerted its antifibrotic effects by regulating amino acid (AA) uptake, mammalian target of rapamycin complex 1 (mTORC1) activation and mesenchyme homeobox1 (MEOX1) expression in activated HLFs. Fittngly, genetic inhibition of macropinocytosis also ameliorated lung fibroblast activation and pulmonary fibrosis in mice. Using IPF-derived precision cut lung slices (PCLS), we observed robust repression of profibrotic gene expression programs in EIPA-treated PCLS across different fibroblast subpopulations. Finally, we found that imipramine (Imi), a tricyclic antidepressant approved by the Food and Drug Administration (FDA), effectively inhibited macropinocytosis and ameliorated profibrotic responses in lung fibroblasts, Bleo-injured mice and IPF-derived PCLS. Taken together, our results suggest macropinocytosis inhibition can be considered as a potential therapeutic strategy to treat pulmonary fibrosis.
Authors
Ivan O. Rosas, Aaron K. McDowell-Sanchez, Santiago Sanchez, Juan D. Cala-Garcia, Alan R. Waich Cohen, Elisa Ruiz-Echartea, Scott A. Ochsner, Daniel C. Kraushaar, Lindsay J. Celada, Dandan Sun, Francesca Polverino, Cristian Coarfa, Neil J. McKenna, Konstantin Tsoyi
Abstract
Coenzyme A (CoA) facilitates fatty acid synthesis, energy production, gene regulation, and antioxidant function. While CoA biosynthesis is well-characterized, the mechanisms governing CoA degradation remain poorly understood. Here, we identify the Metazoan Homolog of SpoT, MESH1, as a CoA phosphatase that dephosphorylates CoA at the 3’ position of the ribose ring to form dephospho-CoA (dp-CoA). Recent studies have shown that CoA, similar to glutathione (GSH), is a cysteine-derived metabolite that protects cells against ferroptosis. Ferroptosis induced by blocking cystine import depletes CoA biosynthesis, while CoA restoration rescues cells from ferroptosis. We found that MESH1 knockdown preserved CoA levels by preventing its degradation, contributing to ferroptosis protection, indicating the bifunctional role of MESH1 in regulating CoA and previously reported NADPH. Mechanistically, MESH1 knockdown elevates CoA levels, maintaining functional mitochondrial thioredoxin system, thereby preventing mitochondrial lipid peroxidation. In Drosophila, we found that dMesh1 overexpression leads to ferroptosis-mediated muscle atrophy, which can be rescued by increasing CoA and NADPH levels. Taken together, these findings establish MESH1 as a key phosphatase that governs ferroptosis sensitivity by coordinating CoA and NADPH homeostasis, unveiling a novel link between CoA degradation, mitochondrial integrity, and muscle health.
Authors
Chao-Chieh Lin, Joshua Rose, Alexander A. Mestre, Chien-Kuang C. Ding, Ssu-Yu Chen, Sze Mun Choy, Kah Yong Goh, Weiyi Jiang, Wen Xing Lee, Qizhou Jiang, Yanting Chen, Tianai Sun, Jianli Wu, Yueqi Chen, Yunju Oh, Pyeonghwa Jeong, Jiyong Hong, Kenon Chua, Michael C. Fitzgerald, Guo-Fang Zhang, Hong-Wen Tang, Pei Zhou, Jen-Tsan Chi
Abstract
Type 1 conventional dendritic cells (cDC1s) play an integral role in mediating immune responses and maintaining homeostasis, yet the molecular mechanisms underlying their functions remain poorly understood. In this study, we identified dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) as a key kinase that responded to TLR and growth factor stimulation and acted as an essential regulator of cDC1 function. Genetic ablation of Dyrk1a specifically in cDC1s impaired antitumor immunity and accelerated tumor progression in murine models. Mechanistically, DYRK1A mediated the phosphorylation of the mTORC1 inhibitor TSC2 at serine 540, triggering the degradation of TSC2 and promoting the mTORC1 signaling in cDC1s. Notably, Tsc2 deletion in Dyrk1a-deficient cDC1s remarkably restored their antitumor immune functions. Furthermore, DYRK1A-mediated mTORC1 signaling in cDC1s positively correlated with effector T-cell responses across multiple human cancers. Our findings highlight a critical role for the DYRK1A-TSC2-mTORC1 signaling pathway in regulating cDC1 functions in antitumor immunity, offering potential strategies to improve cancer immunotherapy.
Authors
Hongjiao Wang, He Jiang, Songlin He, Songwen Ren, Haiwen Li, Wangnan Liu, Chunyun Zhou, Pan Zhu, Keren Chen, Weijia Cao, Yan Qin, Dan Du, Nengming Xiao, Hongling Huang, Chun-Jung Ko, Yiming Zheng, Bo Wang, Qiang Zou, Jian-Hong Shi, Xun Li, Zuliang Jie
Abstract
BORCS5 encodes a subunit of the BLOC-One-Related Complex (BORC), which is known to promote anterograde movement and fusion of lysosomes. We identified 16 individuals from nine families with bi-allelic BORCS5 variants, revealing a spectrum of neurodevelopmental and neurodegenerative phenotypes. Carriers of homozygous protein-truncating variants (PTVs), resulting in complete loss of BORCS5, presented with prenatally lethal arthrogryposis multiplex congenita, brain malformations, and neuropathological evidence of neuroaxonal dystrophy. Individuals with missense or splice-site variants presented differently, with microcephaly, developmental epileptic encephalopathy, optic atrophy, spasticity, and progressive movement disorders. In this group, brain MRI showed diffuse hypomyelination, corpus callosum abnormalities, as well as progressive global cerebral atrophy, consistent with neurodegeneration. Borcs5 knockout in zebrafish exhibited microcephaly, motor deficits, and increased seizure susceptibility, mirroring the patients’ clinical presentation. At the cellular level, only BORCS5 PTVs, but not missense variants, led to perinuclear lysosomal clustering and impaired lysosomal axonal trafficking in induced pluripotential stem cell-derived forebrain neurons. However, both PTVs and missense variants were associated with reduced lysosomal proteolysis and activity of lysosomal hydrolases glucocerebrosidase and cathepsin B, indicating lysosomal dysfunction. Our study reveals a role for BORCS5 in modulation of lysosomal function, in addition to its known role in lysosome movement and fusion, possibly underlying the diverse clinical manifestations in individuals with BORCS5-related disorders.
Authors
Niccolò E. Mencacci, Georgia Minakaki, Reza Maroofian, Raffaella De Pace, Adeline Paimboeuf, Tiago Branco Fonseca, Tatiana Abramova, Patrick Shannon, David Chitayat, Francesca Magrinelli, Wesley J. Peng, Diptaman Chatterjee, Sara H. Eldessouky, Julia Baptista, Tamas Marton, Julie Vogt, Juan Dario Ortigoza-Escobar, Loreto Martorell, Marta Gómez-Chiari, Ingrid M. Wentzensen, Erik-Jan Kamsteeg, Maha S. Zaki, Annarita Scardamaglia, Giovanni Zifarelli, Zuhair Nasser Al-Hassnan, Elka Miller, Shiri Shinar, Lova S. Matsa, Sri Hari Chandan Appikonda, Ghada A. Otaify, Khalid Al-Thihli, Almundher Al-Maawali, Michael Schwake, Mariasavina Severino, Henry Houlden, Shunmoogum A. Patten, Juan S. Bonifacino, Kailash P. Bhatia, Dimitri Krainc
Abstract
Lineage plasticity underscores the resilience of cancer cells in the context of drug treatment. However, lineage fates can also be therapeutically directed. We demonstrate that the eukaryotic initiation factor 4E (eIF4E) cap-binding domain is a critical regulator of lineage plasticity in prostate cancer. Using a first-in-class cap-binding domain inhibitor, we found that plasticity is driven by translational repression of basal keratins through a shared cis-regulatory element enciphered in their 5' untranslated regions (UTRs). Simultaneously this stabilized the androgen receptor (AR) through translational upregulation of the deubiquitinases BAP1 and OTUD3. This lineage program is essential for cell survival and drives a druggable vulnerability. Notably, tumors resistant to AR blockade regained sensitivity upon eIF4E cap-binding domain inhibition, which reprogrammed them toward a luminal state. In castration-resistant prostate cancer (CRPC) patients, elevated eIF4E expression was associated with a basal phenotype, reduced luminal differentiation and accelerated resistance to AR pathway inhibitors (ARPIs). These discoveries uncover a role for the eIF4E cap-binding domain in lineage plasticity and highlight that targeting this domain offers a promising strategy to overcome treatment resistance in prostate cancer.
Authors
Rashmi Mishra, Sihyeon Song, Dhruv Choradia, Dmytro Rudoy, Cynthia L. Wladyka, Patrick Hoang, Jin Yeong Kim, Ilsa M. Coleman, Sonali Arora, Stephanie Dobersch, Alexander E. Orellana, ChenWei Lin, Philip R. Gafken, Eva Corey, Peter S. Nelson, Sita Kugel, Haolong Li, Arnab Sengupta, Andrew C. Hsieh
Abstract
Complete response is rarely observed in lung cancer molecular targeted therapy, despite great clinical success. Here, we found that molecular therapy targeted toward EGFR mutant, KRAS mutant, or ALK fusion lung cancer induced cholesterol biosynthesis, which promoted cancer cells to enter dormancy and thus escape drug killing. Combined statin treatments effectively blocked cholesterol biosynthesis, prevented cancer cells from entering dormancy, and thus resulted in dramatic tumor regression. We further identified a subpopulation of cycling cancer cells that persisted during molecular targeted therapy and remained sensitive to aurora kinase inhibitors. Triple-targeting cholesterol biosynthesis, aurora kinase, and individual oncogenic drivers almost eradicated all the cancer cells. Therapy-induced cancer dormancy was mainly attributed to activation of unfolded protein response, specifically the PERK-eIF2α axis, which triggers cholesterol biosynthesis and AKT signaling. Collectively, this work uncovers an unexpected role of a therapy-induced prosurvival program in promoting cancer dormancy and provides a potentially effective strategy to prevent drug resistance.
Authors
Yikai Zhao, Yijia Zhou, Linnuo Pan, Geng G. Tian, Hsin-Yi Huang, Shijie Tang, Ming Lu, Zhangsen Zhou, Peng Zhang, Luonan Chen, Lele Zhang, Liang Hu, Hongbin Ji
Abstract
Glutathione (GSH) maintains a reduced cellular environment and is widely believed to mitigate disease-associated oxidative damage to proteins, thereby protecting against metabolic dysfunction–associated steatotic liver disease (MASLD). However, this widely accepted assumption remains largely untested because of challenges in physiologically manipulating hepatic GSH levels during disease development. Here, we have utilized liver-specific overexpression of cation transport regulator homolog 1 (Chac1), a recently identified intracellular GSH-degrading enzyme, to induce hepatic GSH depletion during MASLD progression. Contrary to canonical doctrine, GSH depletion unexpectedly protects against MASLD by substantially decreasing hepatic lipogenesis and fibrosis without triggering an oxidative stress response. Mechanistically, GSH depletion does not cause global protein oxidation but instead selectively oxidizes and destabilizes fatty acid synthase while decreasing lipogenic gene expression at the transcriptional level, collectively suppressing lipogenesis. Interestingly, Chac1 expression is decreased in livers of patients with MASLD, highlighting its potential therapeutic relevance. These findings revise the conventional view of GSH in protein redox and demonstrate that targeted redox manipulation through GSH depletion protects against MASLD.
Authors
Xiang-Yu Liu, Guoxiao Wang, Yingying Yu, Haopeng Xiao, Kentaro Oh-hashi, Xu Shi, Shuning Zheng, Robert Gerszten, C. Ronald Kahn
Abstract
Thyroid hormones (THs [T3 and T4] ) are key regulators of metabolic rate and nutrient metabolism. They are controlled centrally and peripherally in a coordinated manner to elegantly match T3-mediated energy expenditure (EE) with energy availability. Hypothyroidism reduces EE and has long been blamed for obesity; however, emerging evidence suggests that, instead, obesity may drive thyroid dysfunction. Thus, we used a mouse model of diet-induced obesity to determine its direct effects on thyroid histopathology and function, deiodinase activity, and T3 action. Strikingly, overnutrition induced hypothyroidism within 3 weeks. Levels of thyroidal THs and their precursor protein thyroglobulin decreased, and ER stress was induced, indicating that thyroid function was directly impaired. We also observed pronounced histological and vascular expansion in the thyroid. Overnutrition additionally suppressed T4 activation, rendering the mice resistant to T4 and reducing EE. Our findings collectively show that overnutrition deals a double strike to TH biosynthesis and action, despite large efforts to adapt — but, fortunately, thyroid dysfunction in mice can be reversed by weight loss. In humans, BMI correlated with thyroidal vascularization, importantly demonstrating preliminary translatability. These studies lay the groundwork for obesity therapies that tackle hypothyroidism, which are much needed, as no current obesity treatment works for everyone.
Authors
Jessica Rampy, Alejandra Paola Torres-Manzo, Kendra Hoffsmith, Matthew A. Loberg, Quanhu Sheng, Federico Salas-Lucia, Antonio C. Bianco, Rafael Arrojo e Drigo, Huiying Wang, Vivian L. Weiss, Nancy Carrasco
Abstract
Mucociliary clearance (MCC) is an innate defense mechanism that normally keeps airways clean but is dysfunctional in cystic fibrosis (CF) and other muco-obstructive pulmonary diseases. Previously we discovered that activating adenyl cyclase in combination with a cholinergic agonist increased MCC velocity (MCCV) synergistically in ex vivo WT and CF ferret and WT piglets. The present study extends and underpins our earlier findings by showing for the first time, in vivo synergistic MCC in WT rats and in CF sheep models and CF rats using inhalable β-adrenergic and cholinergic drugs approved for human use when delivered to the apical surface and a single dose is tolerated by humans. As for mechanisms via ex vivo experiments, we show the combined agonists increased net fluid secretion mainly by stimulating gland secretion and by inhibiting surface absorption, consequently increased ASL depth. They also increased net base secretion and increased ciliary beat frequency. Additional ex vivo and in vitro experiments show that the combined agonists have additive effects when combined with highly effective CF transmembrane conductance regulator (CFTR) modulator therapy (HEMT). The synergistic increase in MCCV induced by this combination of agonists offers therapeutic potential for treating muco-obstructive pulmonary diseases including CF.
Authors
Nam Soo Joo, Susan E. Birket, Johnathan D. Keith, Juan P. Ianowski, Xiaojie Luan, Jacquelyn Spano, Jennifer B. Bollyky, Marissa N. Dobry, Juan R. Sabater, Ryan W. Williams, John F. Engelhardt, Jeffrey J. Wine, Carlos E. Milla
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH) are leading causes of cirrhosis and hepatocellular carcinoma. Defects in autophagy contribute to the development of MASLD, however, the role of the Unc-51-like autophagy-activating kinase 1 (ULK1) in the pathophysiology of MASLD remains unclear. Herein, we show that ULK1, a serine/threonine kinase and core autophagy protein, is significantly repressed in human MASH livers, and that hepatocyte-specific loss of ULK1, unexpectedly, promotes hepatic steatosis and progression to liver fibrosis, without affecting basal autophagy flux. Phospho-proteomics identified the transcriptional coactivator NCOA3 as a downstream phospho-target of ULK1. Mechanistically, ULK1 phosphorylates NCOA3 to repress its transcriptional activity and restrain the CREB/CBP-mediated de novo lipogenic program. Accordingly, a phosphorylation-deficient NCOA3 mutant drives CREB/CBP-mediated lipogenesis, whereas genetic or pharmacological NCOA3 inhibition prevents steatosis, hepatic inflammation, and profibrotic signaling. Hence, ULK1-mediated NCOA3 phosphorylation is a fundamental and druggable checkpoint against the entire MASLD spectrum.
Authors
Young Do Koo, Romilia Tatiana Castillo, Asha Sukumaran Nair, Michael Garneau, Chad Gochee, Zachary V. Campbell, Tashya Shreyas Vakil, Jua Ha, Alex Marti, Jamie Soto, Debajyoti Das, Nuria Martinez-Lopez, Shipra Sharma, Yennifer Delgado, Callie Phung, Immy A. Ashley, Edmund D. Kapelczak, Rashel Jacobo, Eric T. Weatherford, Dao-Fu Dai, Jihane N. Benhammou, Andrea G. Marshall, Antentor Hinton Jr, Ling Yang, Renata O. Pereira, Tara TeSlaa, Mehdi Bouhaddou, Rajat Singh, E. Dale Abel
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ISSN: 0021-9738 (print), 1558-8238 (online)