Cell biology
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
Abstract
Cilia are cellular organelles extruding from the surface of various cell types, serving either sensory or motile functions. Retinitis pigmentosa GTPase regulator (RPGR) variants affect both photoreceptor sensory cilia and airway motile cilia, leading to retinitis pigmentosa (RP) and primary ciliary dyskinesia (PCD), respectively. Not all patients develop PCD, and it remains unclear which RPGR variants predispose patients to PCD. Here, we leverage 2D organoids, super-resolution microscopy, and live-cell imaging to characterize the multiciliated cells (MCCs) from patients with different RPGR variants and CRISPR-modified RPGR KO MCCs. We demonstrate that MCCs with RPGR variants have reduced ciliation, shorter cilia, impaired cilia beat, or cilia beat incoordination, potentially resulting in compromised mucociliary clearance and lung diseases. Moreover, we show that RPGR regulates motile cilia through interfering with F-actin dynamics, evidenced by the undissolved F-actin meshwork in RPGR-deficient MCCs, and the defects can be ameliorated with either Latrunculin A or Y27632 treatment. Though PCD was observed only in patients with variants that affect both isoforms, patients with RPGRORF15 variants also showed cilia and airway anomalies. All RPGR variants affect motile cilia one way or another, and the mechanisms involve the accumulation of apical F-actin.
Authors
Yang Wu, Erika Tavares, Binrun Liang, Wallace B Wee, Vito Mennella, Han-Chao Feng, Jiaying Cao, Pui Yee Wong, Jiayi Zheng, Mu He, Kirk AJ Stephenson, Liran Hanan Hochma, Janice Min Li, Nan-Peng Chen, Sharon D Dell, Elise Heon, ZHEN LIU
Abstract
The peritoneal cavity contains a large population of GATA6-expressing large peritoneal macrophages (LPMs), known to support healing of intra-abdominal organs. In this study, we aimed to explore their full sphere of influence by examining their ability to perform wound healing at distant sites outside the cavity. In a mouse model combining a remote skin injury with peritoneal stimulation we observed a significant acceleration of skin wound healing in response to LPM activation. Tracking GATA6-expressing LPMs, we demonstrated that LPMs do not migrate to distant wound sites following peritoneal activation. Using parabiosis experiments and administration of activated peritoneal contents indicated an important role of molecules secreted by LPMs in remote skin wound healing. More specifically, proteomic and transcriptomic analyses identified fibronectin as a key factor produced by activated LPMs. In fact, depletion of LPMs or genetic knockout of fibronectin in myeloid cells eliminated the enhanced healing effect. These findings highlight the endocrine function of LPMs in systemic tissue repair, challenging the traditional perspective of plasma fibronectin being exclusively liver-derived. Our results suggest that LPMs, strategically positioned in the peritoneal cavity, serve as a source of circulating fibronectin, promoting matrix formation and accelerating wound healing at distant sites.
Authors
Lilian Salm, Simone N. Zwicky, Daniel Spari, Tural Yarahmadov, Marie Siwicki, Fernanda VS Castanheira, Jonas Zbinden, Deborah Stroka, Joel Zindel, Antoine Dufour, Paul Kubes, Guido Beldi
Abstract
Airway mucus clearance from the lungs occurs by two widely recognized mechanisms: cilia-mediated clearance and high-velocity airflow-mediated cough clearance. However, a potentially important third mechanism of mucus clearance, referred to as cilia-independent gas-liquid transport (GLT), was proposed based on in vitro model systems to occur during normal tidal breathing, but has largely been overlooked. To investigate the role of tidal breathing airflow rates in mucus clearance, we conducted a series of in vitro and in vivo studies. An in vitro airway culture bead-tracking model demonstrated airflow-dependent mucus transport at tidal breathing flow rates. As with other modes of mucus clearance, GLT was critically dependent on mucus concentration. In vivo studies in cilial beat-deficient mice demonstrated that GLT-mediated mucus clearance occurs during tidal-breathing in the absence of cough, and the rate of GLT mucus clearance was dependent on breathing frequency and body orientation. These studies demonstrated that GLT represents a third mechanism of mucus clearance and likely represents a significant mode of clearance in persons with cilial dysfunction. These findings indicate that increasing breathing rates through exercise, using mucus rehydrating agents or mucolytics, or combining these approaches may restore clinically and physiologically meaningful airway clearance in these patients.
Authors
Siddharth K. Shenoy, Mark Gutay, Ian Brown, Troy D. Rogers, Kane Banner, Nico Olegario, Nicholas Griffin, Henry P. Goodell, Bryan Yoder, David S. Lalush, David A. Edwards, Richard C. Boucher, Barbara R. Grubb, Brian Button
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ISSN: 0021-9738 (print), 1558-8238 (online)