bims-lypmec Biomed News
on Lysosomal positioning and metabolism in cardiomyocytes
Issue of 2026–07–19
eight papers selected by
Satoru Kobayashi, New York Institute of Technology



  1. Methods Cell Biol. 2026 ;pii: S0091-679X(26)00123-8. [Epub ahead of print]209 27-40
      The Lysosomal Galectin Puncta Assay is a microscopy-based technique able to detect even minor lysosomal leakage with high sensitivity. This protocol describes the detection of galectin puncta as markers of lysosomal membrane permeabilization, a process that relies on the high-affinity binding of the cytosolic galectins to the luminal glycans exposed on damaged lysosomes. Compared to traditional methods, the Galectin Puncta Assay offers high sensitivity, detects subtle lysosomal leakage, and enables analysis at single-lysosome level. Here, we provide a step-by-step protocol for this assay, covering sample preparation, immunostaining, imaging and image quantification.
    Keywords:  Galectin puncta; Lysosomal leakage; Lysosomal membrane permeabilization
    DOI:  https://doi.org/10.1016/bs.mcb.2026.04.002
  2. Nat Cell Biol. 2026 Jul 15.
      Lysosomes are essential regulators of cellular homeostasis. Emerging evidence positions lysosomes as both vulnerable targets and active drivers of ageing biology. During ageing, lysosomes exhibit impaired biogenesis, defective acidification, reduced hydrolytic activity and compromised membrane integrity. These defects impair the clearance of damaged organelles and macromolecules and promote cellular stress responses, inflammageing and senescence, causing age-dependent functional decline across tissues. Lysosomal dysfunction has been increasingly linked to age-related diseases, including neurodegeneration, cardiometabolic disorders and increased susceptibility to infection, among others. Thus, lysosomal dysfunction is a hallmark of ageing that drives age-related pathology. Here we review recent progress in lysosomal biogenesis and quality control, discuss how lysosomes intersect with fundamental ageing mechanisms and evaluate emerging therapeutic strategies that target lysosomes to promote healthy ageing and potentially ameliorate age-associated pathologies.
    DOI:  https://doi.org/10.1038/s41556-026-02007-6
  3. Molecules. 2026 Jul 06. pii: 2373. [Epub ahead of print]31(13):
      Ferroptosis is a regulated form of cell death characterized by iron-dependent lipid peroxidation and membrane damage, with broad relevance to human disease. Accumulating evidence suggests that ferroptosis is governed by coordinated organelle-level regulation, among which lysosomes have emerged as central hubs. By controlling endolysosomal iron processing, transport, and degradation pathways, lysosomes shape the intracellular distribution and reactivity of iron, thereby modulating iron-driven lipid peroxidation. The acidic, iron-rich microenvironment and limited local antioxidant capacity render lysosomal membranes highly susceptible to oxidative injury, positioning lysosomes as initiation and amplification sites of lipid peroxidation. Meanwhile, lysosome-dependent selective autophagy pathways actively remodel iron homeostasis, lipid metabolism, and cellular antioxidant defenses, thereby dynamically modulating ferroptotic sensitivity. Mitochondria-lysosome crosstalk further redistributes iron, reactive oxygen species, and lipid substrates, linking lysosomal activity to interorganelle control of ferroptosis. Lysosomal stress-responsive signaling also coordinates metabolic adaptation and redox control. This review summarizes and integrates current evidence on lysosome-centered mechanisms that organize iron metabolism, lipid peroxidation, selective autophagy, organelle crosstalk, and stress-responsive signaling during ferroptosis, and further discusses their disease-specific roles, therapeutic potential, and translational challenges.
    Keywords:  autophagy; ferroptosis; iron metabolism; lysosomes; oxidative stress
    DOI:  https://doi.org/10.3390/molecules31132373
  4. Autophagy Rep. 2026 ;5(1): 2698348
      Macroautophagy is an intracellular degradation process that relies on autophagosomes and lysosomes to maintain cellular and organismal homeostasis. Actin cytoskeletal rearrangements driven by the Arp2/3 (actin-related protein 2/3) complex, an essential actin nucleator, impact multiple steps of this pathway, but where and when Arp2/3-mediated actin assembly is most influential has remained unclear. Recent work now shows that the Arp2/3 complex is crucial in the later stages of autophagy due to its function in maintaining lysosomal integrity. WHAMM (WASP homolog associated with actin, membranes, and microtubules) is the key nucleation-promoting factor that activates Arp2/3 at permeabilized lysosomes, uncovering new roles for actin, the Arp2/3 complex, and WHAMM in lysosomal damage responses.
    Keywords:  ATG8; Actin; Arp2/3 complex; JMY; LC3; WASP; WHAMM; autophagy; cytoskeleton; lysosome
    DOI:  https://doi.org/10.1080/27694127.2026.2698348
  5. Int J Mol Sci. 2026 Jun 24. pii: 5716. [Epub ahead of print]27(13):
      Circulating ketone bodies (KBs), particularly β-hydroxybutyrate (β-HB), have emerged as metabolites with dual roles as both oxidative fuels and metabolic signaling molecules. Beyond serving as an alternative energy substrate, β-HB regulates diverse pathways involved in oxidative stress, inflammation, and mitochondrial function. However, the clinical implications of circulating KBs remain uncertain. This review summarizes current evidence regarding the potential role of KBs in glycemic progression and diabetic cardiomyopathy (DCM). Epidemiologic and experimental studies report conflicting associations between KB levels and the progression to hyperglycemia or type 2 diabetes, with some findings suggesting that elevated KB levels may reflect a metabolically favorable phenotype or a compensatory mechanism, whereas others indicate links to worsening glycemia. Similarly, studies in DCM have produced divergent results, with β-HB reported to improve mitochondrial function and cardiac performance in some models while contributing to metabolic inflexibility and adverse cardiac remodeling in others. We discuss potential mechanisms underlying these discrepancies and propose that the metabolic effects of β-HB are context-dependent, influenced by factors such as circulating concentration, the mode of ketosis induction, and the underlying metabolic or disease stage. Understanding these contextual determinants may help clarify whether β-HB represents an adaptive metabolic signal or a maladaptive substrate shift in cardiometabolic disease.
    Keywords:  diabetic cardiomyopathy; glycemic progression; ketone bodies; mitochondrial function; type 2 diabetes; β-hydroxybutyrate
    DOI:  https://doi.org/10.3390/ijms27135716
  6. Trends Mol Med. 2026 Jul 17. pii: S1471-4914(26)00169-3. [Epub ahead of print]
      Ferroptosis is a unique form of programmed cell death that involves multiple organelles. Although traditionally viewed as a 'degradation workshop', accumulating evidence reveals that the lysosome serves as a central hub for iron metabolism and signal transduction, orchestrating the overall fate of cellular ferroptosis across spatiotemporal dimensions. In this review, we propose the concept of the 'lysosome-ferroptosis axis' and outline its roles in metabolic signaling, autophagy, and lysosomal membrane permeabilization. We further discuss the involvement of this axis in neurodegenerative, tumor, and cardiometabolic diseases, with the aim of providing new insights for targeted therapeutic strategies.
    Keywords:  cancer; cardiometabolic disorder; ferroptosis; lysosome; neurodegenerative disorder
    DOI:  https://doi.org/10.1016/j.molmed.2026.06.016
  7. Free Radic Biol Med. 2026 Jul 16. pii: S0891-5849(26)00955-X. [Epub ahead of print]
      Diabetes, a systemic metabolic disorder, often involves multi-organ interactions in its complications. Although the pathogenesis of diabetic cardiomyopathy (DCM) is complex, the role of the liver in this process remains unclear. Using the db/db mouse model, this study demonstrated that metabolic dysfunction associated steatotic liver disease (MASLD) reduced hepatic synthesis of hemopexin (HPX) and impaired Kupffer cell function, leading to systemic heme accumulation. This circulating heme was taken up by cardiomyocytes via the membrane protein feline leukemia virus subgroup C receptor 2 (FLVCR2), which induced cardiomyocyte pyroptosis and aggravated myocardial injury. Intervention experiments indicated that targeted supplementation of hepatic HPX effectively restored heme homeostasis, reduced exogenous heme influx into cardiomyocytes, and improved cardiac function. These findings reveal a liver-heart axis mechanism in which hepatic heme mediates cardiomyocyte pyroptosis through FLVCR2, offering novel perspectives for the prevention and treatment of DCM.
    Keywords:  Diabetic cardiomyopathy (DCM); Heme; Liver-heart axis; Pyroptosis
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2026.07.028
  8. J Cell Biol. 2026 Sep 07. pii: e202605090. [Epub ahead of print]225(9):
      Fatty acids (FAs) are transported from lipid droplets (LDs) to mitochondria for β-oxidation during cell starvation. Starvation also triggers engulfment of LDs by autophagosomes and their subsequent degradation by lysosomes (lipophagy). The mechanisms coordinating these pathways remain unclear. Here, we demonstrate that PISD-LD, an LD-localized isoform of phosphatidylserine decarboxylase, facilitates FA transfer while inhibiting lipophagy. PISD-LD mediates LD-mitochondrion (LD-mito) contacts via interaction with mitochondrial PISD. In PISD-LD KD cells, LDs are larger, and FA trafficking and mitochondrial FA β-oxidation are suppressed. The lipid transfer proteins ATG2A/B are recruited by PISDs to mediate FA transfer from LDs to mitochondria. Disruption of PISD-LD-mediated LD-mito contacts activates lipophagy, aiding LD degradation. PISD-LD binds the lipophagy receptor Spartin and inhibits lipophagy by impeding Spartin-LC3 interaction. PISD-LD also regulates LD-mito contacts and lipid metabolism in mouse liver. Thus, PISD-LD serves as a switch between LD-to-mitochondrion FA transfer and lipophagy, ensuring efficient energy production.
    DOI:  https://doi.org/10.1083/jcb.202605090