He, M.* ; Ding, M.* ; Chocholoušková, M.* ; Chin, C.F.* ; Engvall, M.* ; Malmgren, H.* ; Wagner, M. ; Lauffer, M.C.* ; Heisinger, J.* ; Malicdan, M.C.V.* ; Allamand, V.* ; Durbeej, M.* ; Delgado-Vega, A.M.* ; Sejersen, T.* ; Nordgren, A.* ; Torta, F.* ; Silver, D.L.*
     
    
        
SPNS1 variants cause multi-organ disease and implicate lysophospholipid transport as critical for mTOR-regulated lipid homeostasis.
    
    
        
    
    
        
        J. Clin. Invest. 135:e193099 (2025)
    
    
    
      
      
	
	    SPNS1 is a lysosomal transporter mediating the salvage of lysoglycerophospholipids, the degradative products of lysosomal phospholipid catabolism. However, a role of lysolipid transport and salvage in regulating cellular lipid homeostasis and in disease is lacking. Here, we identified two families with biallelic SPNS1 loss-of-function variants that presented primarily with progressive liver and striated muscle injury. Patient fibroblasts accumulated lysophospholipids including lysoplasmalogens and cholesterol in lysosomes with reduced cellular plasmalogens. Notably, SPNS1 deficiency resulted in reduced biogenesis of cytosolic lipid droplets containing triglycerides and cholesteryl esters. Mechanistically, we found that lysophospholipids transported by SPNS1 into the cytosol quantitatively contributed to triglyceride synthesis while lysosomal buildup of lyso-ether-phospholipid inhibited lysosomal cholesterol egress, effects that were enhanced with inhibition of mTOR. These findings support a gene-disease association and reveal connectivity between lysosomal transport of lysophospholipids and storage of reserve cellular energy as triglyceride and in the regulation of cholesterol homeostasis, processes that become important under nutrient limitation.
	
	
	    
	
       
      
	
	    
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        Publication type
        Article: Journal article
    
 
    
        Document type
        Scientific Article
    
 
    
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        Keywords
        Cell Biology ; Cholesterol ; Lipidomics ; Lysosomes ; Metabolism
    
 
    
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        Language
        english
    
 
    
        Publication Year
        2025
    
 
    
        Prepublished in Year
        0
    
 
    
        HGF-reported in Year
        2025
    
 
    
    
        ISSN (print) / ISBN
        0021-9738
    
 
    
        e-ISSN
        1558-8238
    
 
    
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	    Volume: 135,  
	    Issue: 17,  
	    Pages: ,  
	    Article Number: e193099 
	    Supplement: ,  
	
    
 
    
        
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            American Society of Clinical Investigation
        
 
        
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        Reviewing status
        Peer reviewed
    
 
     
    
        POF-Topic(s)
        30205 - Bioengineering and Digital Health
    
 
    
        Research field(s)
        Genetics and Epidemiology
    
 
    
        PSP Element(s)
        G-503200-001
    
 
    
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        Erfassungsdatum
        2025-07-16