MASLD/MASH is not just “fatty liver.” It is a systemic metabolic disease where adipose tissue dysfunction, insulin resistance, glucagon imbalance, gut–liver signaling, and mitochondrial stress converge into inflammation and fibrosis. Key mechanisms: 🧈 Adipose tissue failure → hepatic lipid overload Dysfunctional adipose tissue loses its lipid-buffering capacity, increasing NEFA and glycerol delivery to the liver. This fuels steatosis, lipotoxicity, insulin resistance, and inflammatory signaling. 🔥 Metabolic stress → metaflammation Excess NEFAs, DAGs, ceramides, glucose, fructose, and amino acids overload hepatocyte metabolism. Mitochondrial dysfunction, ER stress, ROS, apoptosis, and DAMP release activate Kupffer cells and recruited macrophages. 🧬 Fibrosis is the key outcome driver Chronic hepatocyte injury and macrophage cytokines activate hepatic stellate cells, leading to extracellular matrix deposition and progressive fibrosis. Fibrosis stage—not steatosis alone—is the major predictor of clinical outcome. ⚖️ Hormonal imbalance matters Hyperinsulinaemia promotes DNL and may directly activate HSC profibrotic signaling. Hyperglucagonaemia and selective glucagon resistance disturb glucose, lipid, and amino acid metabolism. Impaired incretin signaling further worsens metabolic flexibility. 🦠 Gut–liver–adipose axis amplifies injury Dysbiosis, increased permeability, LPS, altered bile acids, and microbial metabolites activate TLR/NLRP3/NF-κB pathways, reinforcing hepatic inflammation and fibrogenesis. 💊 Therapeutic map Mechanism-based targets include: • THR-β agonists: reduce lipotoxicity and fibrosis • GLP-1/GIP/glucagon-based agents: reduce weight, steatosis, and metabolic stress • PPAR agonists: improve adipose insulin sensitivity and inflammatory/fibrotic signaling • FGF19/FGF21 analogues: coordinate liver–adipose–CNS metabolic remodeling Take-home: MASLD progression is driven by multi-organ metabolic crosstalk. Precision therapy will likely require matching patients to dominant disease drivers: adipose insulin resistance, hyperinsulinaemia, glucagon dysregulation, mitochondrial stress, gut-derived inflammation, or fibrogenic HSC activation.

🧬 Can microplastics rewire liver biology at single-cell resolution? A new Science Advances study used spatial transcriptomics, Raman spectroscopy, and O-PTIR imaging to map how polyethylene (PE) microplastics remodel the liver microenvironment. Key findings: 🔹 Chronic PE exposure induced hepatotoxicity and worsened MASH-like pathology in mice. 🔹 Bulk RNA-seq revealed major disruption of lipid metabolism pathways and activation of nuclear receptor programs, including increased Ppara expression. 🔹 Xenium spatial transcriptomics uncovered inflammatory hotspots with reduced cellular diversity, loss of Kupffer-cell abundance, and expansion of midlobular hepatocyte populations. 🔹 Spatial analysis identified Anxa2 as a PE-responsive gene specifically enriched in high-inflammation pericentral hepatocytes. 🔹 Mechanistically, PPARα directly bound Anxa2 enhancer/promoter regions, and pharmacologic activation of PPARα increased Anxa2 expression, while PPARα inhibition or knockdown abolished PE-induced Anxa2 upregulation. 🔹 Raman and O-PTIR imaging confirmed polyethylene particle localization within liver tissue and demonstrated proximity to Kupffer-cell–rich inflammatory niches. Why it matters: Most microplastic liver studies have focused on polystyrene. This work instead investigates polyethylene—the most abundant microplastic detected in humans—and provides one of the first spatially resolved maps linking environmental microplastic exposure to hepatic transcriptional remodeling. The emerging model: PE accumulation → inflammatory niche formation → PPARα activation → ANXA2 induction → hepatocyte stress adaptation / tissue remodeling Beyond toxicology, the study highlights how environmental exposures reshape tissue architecture and cell-cell communication in metabolic disease. Paper: Jung et al. Science Advances (2026) “Spatial transcriptome mapping identifies Ppara-Anxa2 cross-talk in microplastic-induced hepatotoxicity” #Microplastics #SpatialTranscriptomics #LiverDisease #MASH #NAFLD #PPARalpha #ANXA2 #SingleCell #ScienceAdvances #EnvironmentalHealth

Aging-associated inflammation ("inflammaging") is a major driver of tissue dysfunction, frailty, and chronic disease. But what if a previously overlooked nucleic acid structure is helping fuel it? A new study in Nature Aging identifies a mechanistic link between R-loops, cellular senescence, and inflammaging. Key findings: 🔹 Senescent cells accumulate cytoplasmic R-loops derived from the nucleus. 🔹 These R-loops localize to cytoplasmic chromatin fragments (CCFs) and activate the cGAS–STING innate immune pathway, driving the senescence-associated secretory phenotype (SASP). 🔹 The study identifies a previously unrecognized transport mechanism: Nuclear R-loop → DDX1 → XPO1 export → CCF localization → cGAS activation → SASP → inflammaging DDX1 acts as an R-loop-binding export adaptor, while XPO1 mediates nuclear export. 🔹 Cytoplasmic R-loops were enriched for alpha-satellite repeat sequences, linking centromeric instability and repetitive-element biology to age-associated inflammation. 🔹 Pharmacologic inhibition of XPO1 using KPT-330 (selinexor): • Reduced cytoplasmic R-loops • Suppressed cGAS-STING signaling • Lowered SASP factors • Reduced liver inflammation and fibrosis • Decreased circulating TNF and IL-6 • Improved body composition • Extended lifespan in aged mice Conceptually, this work introduces R-loop trafficking as a new aging mechanism. Rather than acting solely as nuclear genome-instability intermediates, R-loops can become exported inflammatory signals that couple DNA damage responses to innate immunity. The study positions the: DDX1–XPO1–R-loop–cGAS axis as a potentially druggable pathway for suppressing inflammaging and age-related functional decline. Nature Aging (2026) Hao et al. Nuclear export of R-loop by the DDX1 and XPO1 complex promotes senescence-associated secretory phenotype and inflammaging #Aging #Inflammaging #Senescence #SASP #RLoops #cGAS #STING #DDX1 #XPO1 #Selinexor #Longevity #NatureAging