Biology subjects

Iwakiri, Y.

Publications and source records attributed to Iwakiri, Y..

7 recordsLinked to original sources

bioRxiv2025

A single-cell fixed RNA profiling of liver fibrosis progression and regression reveals SEMA4D and LMCD1 as key mediators of fibrogenesis

Liver fibrosis progression and regression are dynamic processes involving diverse hepatic and immune cell populations. Here, we utilize single-cell fixed RNA profiling (FLEX) of a TAA-induced mouse liver cirrhosis model, with and without a recovery phase, to depict the cellular landscape and molecular mechanisms of fibrosis resolution. The regression phase was characterized by the emergence of pericentral hepatocytes enriched in detoxification and antioxidant genes (e.g., Cyp2e1, Txn1), which secreted Rarres2 to modulate hepatic stellate cell (HSC) function. This was accompanied by the upregulation of scar-resolving genes (Mmp14, Ctsl), restoration of fenestrae in liver sinusoidal endothelial cells, anti-inflammatory phenotypes of Kupffer cells, a decrease in fibrogenic cholangiocyte subsets, and recovery-associated signatures in NK/T cells, B cells, and neutrophils. In contrast, SEMA4D secreted by monocyte-derived macrophages during fibrosis progression activated Plxnb2 HSCs, and its blockade attenuated fibrosis in vivo. Furthermore, LMCD1 was identified as a novel marker for HSC activation and regulation. This single-cell atlas reveals key transcriptional programs and intercellular signaling pathways dependent on the fibrotic condition, offering new therapeutic targets for liver cirrhosis.

cell biology↗

bioRxiv2025

Hepatic Arterial Flow-Induced Portal Tract Fibrosis in Portal Hypertension: The Role of VCAM-1 and Osteopontin-Expressing Macrophages

BackgroundThe liver undergoes significant hemodynamic changes during surgery, transplantation, or cirrhosis with portal hypertension(PH). The hepatic artery buffer response(HABR), which compensates for reduced portal venous flow by increasing hepatic artery(HA) flow, is hypothesized to induce pathological portal tract remodeling. This study investigates the molecular mechanisms underlying this process. MethodsPH was induced in Sprague-Dawley rats via partial portal vein ligation(PPVL). Structural evaluation(microCT), immune cell profiling, hemodynamic measurements, and transcriptomic analysis in macrophages(M{phi}) from sham or PPVL rats were conducted. ResultsMicroCT revealed decreased portal vein flow and increased HA flow correlated with portal pressure(r=0.799, p<0.01). A 2-fold increase in portal tract fibrosis(p<0.001) was observed with increased -SMA+ myofibroblasts in PPVL rats. CD68+ M{phi} peaked at 10 days post-PPVL, and their depletion significantly reduced fibrosis(p<0.001), indicating critical roles of M{phi} in portal tract remodeling. VCAM-1 was elevated in HA endothelium and portal fibroblasts (PFs); VCAM-1 neutralization reduced collagen accumulation(p<0.05), CD68+ M{phi}(46.3%, p<0.01), and CD3+ T cells(18%, p<0.05). M{phi}-conditioned medium increased VCAM-1 in PFs(8-fold, p<0.001) and enhanced PF migration, while VCAM-1 knockdown reduced this effect (p<0.01). Single-cell RNA sequencing data(GSE171904) and RNA-FISH revealed increased interactions between osteopontin (Spp1)+ M{phi} and PFs, with Spp1+ M{phi} driving fibrosis. Spp1 knockdown in M{phi} co-culture reduced PF fibrogenic markers, while recombinant Spp1 upregulated Col1a1, Fn1, and Acta2 expression in PFs. ConclusionIncreased VCAM-1 in arterial endothelial cells and PFs facilitates the recruitment of Spp1+ M{phi}, which drive HA flow-mediated vascular remodeling and portal tract fibrosis. These findings highlight arterial flow-induced fibrosis as a key mechanism in PH, potentially contributing to disease progression and decompensation. SynopsisLiver hemodynamic changes in portal hypertension drive extracellular matrix accumulation and portal tract remodeling via Spp1+ macrophages. This study highlights how altered blood flow induces fibrosis, and its potential role in decompensation, and identifies therapeutic targets for advanced liver disease.

pathology↗

bioRxiv2025

Liver Lymphatic Dysfunction as a Driver of Fibrosis and Cirrhosis Progression

The liver lymphatic system plays a critical role in maintaining interstitial fluid balance and immune regulation. Efficient lymphatic drainage is essential for liver homeostasis, but its role in liver disease progression remains poorly understood. In cirrhosis, lymphangiogenesis initially compensates for increased lymph production, but impaired lymphatic drainage in advanced stages may lead to complications such as ascites and portal hypertension. This study aimed to evaluate how liver lymphatic dysfunction affects disease progression and to assess therapeutic strategies. Using a surgical model to block liver lymphatic outflow, we found that impaired drainage accelerates liver injury, fibrosis, and immune cell infiltration, even in healthy livers. Mechanistically, enhanced TGF-{beta} signaling in liver lymphatic endothelial cells (LyECs) contributed to reduced lymphatic vessel (LV) density and function in late-stage decompensated cirrhosis. This dysfunction was linked to the progression from compensated to decompensated cirrhosis, particularly in patients with primary sclerosing cholangitis (PSC). Conversely, liver-specific overexpression of VEGF-C via AAV8 improved lymphatic drainage, restored LV density, reduced fibrosis, mitigated liver injury, and alleviated portal hypertension in cirrhotic rats. These findings establish impaired liver lymphatic function as a pivotal driver of cirrhosis progression and identify VEGF-C as a promising therapeutic target to prevent decompensation.

pathology↗

bioRxiv2020

Alcohol-induced Hsp90 acetylation is a novel driver of liver sinusoidal endothelial dysfunction and alcoholic liver disease

BackgroundIt is unknown whether liver sinusoidal endothelial cells (LSECs) metabolize alcohol. Chronic alcohol consumption decreases endothelial nitric oxide synthase (eNOS)-derived NO production typical of LSEC dysfunction. Heat shock protein 90 (Hsp90) interacts with eNOS to increase its activity. Cytochrome P450 2E1 (CYP2E1) is a key enzyme in alcohol metabolism and facilitates protein acetylation via acetyl-CoA, but its expression in LSECs is unknown. This study investigates alcohol metabolism by LSECs, the mechanism of alcohol-induced LSEC dysfunction and a potential therapeutic approach for alcohol-induced liver injury. MethodsPrimary human, rat and mouse LSECs were used. Histone deacetylase 6 (HDAC6) was overexpressed specifically in liver ECs using an adeno-associated virus (AAV)-mediated gene delivery system to decrease Hsp90 acetylation in ethanol fed mice. ResultsLSECs expressed CYP2E1 and alcohol dehydrogenase 1 (ADH1) and metabolized alcohol. Ethanol induced CYP2E1 in LSECs, but not ADH1. Alcohol metabolism by CYP2E1 increased Hsp90 acetylation and decreased its interaction with eNOS along with a decrease in NO production. A non-acetylation mutant of Hsp90 increased its interaction with eNOS and NO production, whereas a hyper-acetylation mutant decreased NO production, compared with wildtype Hsp90. These results indicate that Hsp90 acetylation is responsible for decreases in its interaction with eNOS and eNOS-derived NO production. Adeno-associated virus 8 (AAV8)-driven HDAC6 overexpression specifically in liver ECs deacetylated Hsp90, restored Hsp90s interaction with eNOS and ameliorated alcohol-induced liver injury in mice. ConclusionRestoring LSEC function is important for ameliorating alcohol-induced liver injury. To this end, blocking acetylation of Hsp90 specifically in LSECs via AAV-mediated gene delivery has the potential to be a new therapeutic strategy.

molecular biology↗

bioRxiv2020

Enhanced meningeal lymphatic drainage ameliorates neuroinflammation and hepatic encephalopathy in cirrhotic rats

Background and aimsHepatic encephalopathy (HE) is a serious neurological complication in patients with liver cirrhosis. Nothing is known about the role of the meningeal lymphatic system in HE. We tested our hypothesis that enhancement of meningeal lymphatic drainage could decrease neuroinflammation and ameliorate HE. MethodsA 4-week bile duct ligation (BDL) model was used to develop cirrhosis with HE in rats. Brain inflammation in patients with HE was evaluated using archived GSE41919. Motor function of rats was assessed by the rotarod test. AAV8-VEGF-C was injected into the cisterna magna of BDL rats one day after surgery to induce meningeal lymphangiogenesis. ResultsCirrhotic rats with HE showed significantly increased microglia activation in the middle region of the cortex (p<0.001) as well as increased neuroinflammation as indicated by significant increases in IL-1{beta}, INF{gamma}, TNF and Iba1 expression in at least one of the three regions of the cortex. Motor function was also impaired in rats with HE (p<0.05). Human brains of cirrhotic patients with HE also exhibited upregulation of pro-inflammatory genes (NF-{kappa}{beta}, Iba1, TNF and IL-1{beta}) (n=6). AAV8-VEGF-C injection significantly increased meningeal lymphangiogenesis (p=0.035) and tracer dye uptake in the anterior and middle regions of the cortex (p=0.006 & 0.003, respectively), their corresponding meninges (p=0.086 & 0.006, respectively) and the draining lymph nodes (p=0.02). Further, AAV8-VEGF-C decreased microglia activation (p<0.001) and neuroinflammation, and ameliorated motor dysfunction (p=0.024). ConclusionPromoting meningeal lymphatic drainage and enhancing waste clearance improves HE. Manipulation of meningeal lymphangiogenesis could be a new therapeutic strategy for the treatment of HE.

neuroscience↗

bioRxiv2020

Single-cell transcriptomics reveals zone-specific alterations of liver sinusoidal endothelial cells in cirrhosis

Dysfunction of liver endothelial cells (ECs), particularly sinusoidal endothelial cells (LSECs), is permissive for the progression of liver fibrosis/cirrhosis and responsible for its clinical complications. Here, we have mapped the spatial distribution of heterogeneous liver ECs in normal versus cirrhotic mouse livers and identified zone-specific transcriptomic changes of LSECs associated with liver cirrhosis using single-cell RNA sequencing technology. We identified 6 clusters of liver EC populations including 3 clusters of LSECs, 2 clusters of vascular ECs and 1 cluster of lymphatic ECs. To add finer detail, we mapped the 3 clusters of LSECs to Zones 1 to 3. We found that heterogeneous liver EC identities are conserved even in liver cirrhosis and that Zone 3 LSECs are most susceptible to damage associated with liver cirrhosis, demonstrating increased capillarization and decreased ability to regulate endocytosis. Altogether, this study deepens our knowledge of the pathogenesis of liver cirrhosis at a spatial, cell-specific level, which is indispensable for the development of novel therapeutic strategies to target the most highly dysfunctional liver ECs.

cell biology↗

bioRxiv2019

O-GlcNAc transferase suppresses necroptosis and liver fibrosis

Over a billion people suffer from chronic liver diseases worldwide, which often leads to fibrosis and then cirrhosis. Treatments for fibrosis remain experimental, in part because no unifying mechanism has been identified that initiates liver fibrosis. Here we report that O-linked {beta}-N-acetylglucosamine (O-GlcNAc) modification protects against hepatocyte necroptosis and initiation of liver fibrosis. Decreased O-GlcNAc levels were seen in patients with liver cirrhosis and in mice with ethanol-induced liver injury. Liver-specific O-GlcNAc transferase (OGT) knockout (OGT-LKO) mice exhibited ballooning degeneration and elevated circulating alanine aminotransferase (ALT) levels at an early age and progressed to liver fibrosis and portal inflammation by 10 weeks of age. OGT-deficient hepatocytes underwent excessive necroptosis and exhibited elevated protein expression levels of receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like (MLKL), which are key mediators of necroptosis. Furthermore, glycosylation of RIPK3 by OGT reduced RIPK3 protein stability. Taken together, these findings identify OGT as a key suppressor of hepatocyte necroptosis and OGT-LKO mice may serve as an effective spontaneous genetic model of liver fibrosis.

physiology↗