Journal: The EMBO Journal

Article Title: Hepatic ASPG-mediated lysophosphatidylinositol catabolism impairs insulin signal transduction

doi: 10.1038/s44318-025-00525-x

Figure Lengend Snippet: ( A ) Western blot analysis of the indicated proteins in the primary hepatocytes isolated from the WT and Aspg LKO mice. Insulin (10 nM) stimulated the cells for 15 min before harvesting the cells ( n = 3 each group). ( B ) Adenoviruses coding for Aspg (Adv-ASPG) or vector control (Adv-GFP) infected the primary hepatocytes. The cells were stimulated by insulin (10 nM) for 15 min before the western blot assay ( n = 3 each group). ( C , D ) Lipidomic analysis for the liver tissues from the WT and Aspg LKO mice fed a HFD for 20 weeks. A heatmap of the total amount of each species of lysophospholipid was presented in ( C ). The quantification of the major LPI subspecies was shown in ( D ). WT n = 4, LKO n = 3; female. ( E ) The ASPG lysophospholipidase activity assay in vitro. Purified ASPG and lysophospholipid substrates were incubated at 37 °C for the indicated time. The decrease in the substrate levels was subsequently quantified by UHPLC–MS/MS ( n = 6 each time point). ( F ) Primary hepatocytes isolated from female C57BL/6 mice were subjected to treatment as indicated followed by western blot analysis. ( G ) Primary hepatocytes isolated from the female WT and Aspg LKO mice were treated with or without ML-193 (10 μM) for 6 h. Western blot analysis was performed after 15-min insulin (10 nM) stimulation. n = 2 in each group. ( H ) Interactive visualization of LPI 18:0 binding to N-terminus of human PTP1B. The P-loop of PTP1B is shown in red. ( I ) The binding affinity between PTP1B and LPI 18:0 was measured by microscale thermophoresis (MST). Inset, thermophoretic movement of fluorescently labeled proteins. K d , dissociation constant. n = 4 independent measurements. ( J ) The in vitro PTP1B activity assay in the presence of LPI 18:0, LPC 18:0 or LPE 18:0. The PTP1B activity without any lysophospholipids was marked as 1 ( n = 3 each group). Data are represented as mean ± SEM. Statistical analysis was performed by unpaired two-tailed Student’s t test for ( C , D ). For ( F , G ), the experiments were repeated at least for three times and representative images were shown. .

Article Snippet: In order to ascertain the impact of LPI on primary hepatocytes, hepatocytes were treated for 12 h with 5 μM of LPI (Avanti Polar Lipids, #850091 P) and/or 10 μM ML-193 (MCE, #HY-110125) for 6 h. To observe the regulation on Sepp1 expression, primary hepatocytes were treated with 10 nM insulin for 24 h and 5 μM LPI for 12 h with or without 2 μM AKTi (MCE, # HY-10355) for 2 h.

Techniques: Western Blot, Isolation, Plasmid Preparation, Control, Infection, Activity Assay, In Vitro, Purification, Incubation, Tandem Mass Spectroscopy, Binding Assay, Microscale Thermophoresis, Labeling, Two Tailed Test

Journal: The EMBO Journal

Article Title: Hepatic ASPG-mediated lysophosphatidylinositol catabolism impairs insulin signal transduction

doi: 10.1038/s44318-025-00525-x

Figure Lengend Snippet: ( A ) Quantity of the 10 lipid species in liver tissues from the WT and Aspg LKO mice that were fed a HFD for 20 weeks (WT n = 4, LKO n = 3, female). ( B ) Quantity of LPIs in serum from the mice treated as in ( A ) ( n = 5 each genotype, female). ( C , D ) The relative quantity of the intracellular ( C ) and extracellular LPI levels ( D ) in primary hepatocytes. The hepatocytes were isolated from the chow diet-fed male WT and Aspg LKO mice (WT n = 4, LKO n = 6). ( E ) Relative mRNA levels of Gpr55 and Mboat7 in livers from the WT and LKO mice. The mice were fed a HFD for 16 weeks ( n = 5 each group, male). ( F ) Molecular docking revealed interaction of LPI 18:0 with human PTP1B protein. ( G ) The sequence alignment of human and mouse PTP1B proteins. The amino acid residues interacting with LPI were indicated in red. ( H ) The siRNA against PTP1B was used to knockdown PTP1B in the primary hepatocytes. Western blot analysis of the indicated proteins was performed after insulin (10 nM) treatment for 15 min. ( I ) The siRNA against PTP1B was used to knockdown PTP1B in the primary hepatocytes followed by LPI (10 μM) treating the cells for 12 h. Western blot analysis was performed after insulin (10 nM) treatment for 15 min. For all: Data are represented as mean ± SEM. Statistical analysis was performed by unpaired two-tailed Student’s t test for ( A – E ). .

Article Snippet: In order to ascertain the impact of LPI on primary hepatocytes, hepatocytes were treated for 12 h with 5 μM of LPI (Avanti Polar Lipids, #850091 P) and/or 10 μM ML-193 (MCE, #HY-110125) for 6 h. To observe the regulation on Sepp1 expression, primary hepatocytes were treated with 10 nM insulin for 24 h and 5 μM LPI for 12 h with or without 2 μM AKTi (MCE, # HY-10355) for 2 h.

Techniques: Isolation, Sequencing, Knockdown, Western Blot, Two Tailed Test

Journal: The EMBO Journal

Article Title: Hepatic ASPG-mediated lysophosphatidylinositol catabolism impairs insulin signal transduction

doi: 10.1038/s44318-025-00525-x

Figure Lengend Snippet: ( A ) Relative mRNA levels of Sepp1 in livers (left, n = 5 female) and SELENOP protein levels in serum (right, WT n = 8, LKO n = 6, female) from the WT and Aspg LKO mice that were fed a HFD for 20 weeks. ( B ) Adenoviruses expressing Aspg (Adv-ASPG) or the vector control (Adv-GFP) infected the primary hepatocytes followed by with or without palmitate (200 μM) treating the cells for 24 h. Then the mRNA levels of Aspg and Sepp1 were determined by quantitative real-time PCR ( n = 3 each group). ( C ) The SELENOP protein levels in the culture medium of cells in ( B ) ( n = 3 each group). ( D ) Conditional medium collected from primary hepatocytes overexpressing Adv-ASPG after palmitic acid treatment for 24 h was applied to 3T3L1 adipocytes for 48 h. Western blot analysis of the phosphorylation and total protein levels of INSR and AKT in 3T3L1 adipocytes ( n = 3). ( E , F ) Lentiviral Foxo1 shRNA infected mouse primary hepatocytes followed by treatment with palmitate (36 h), insulin (24 h). Sepp1 mRNA ( E ) and SELENOP protein levels ( F ) were measured ( n = 5 each group). ( G ) Relative mRNA levels of Sepp1 in the primary hepatocytes isolated from the WT and Aspg LKO mice. The cells were treated with or without AKTi (2 μM) for 2 h before the assay ( n = 3 each group). ( H ) Relative mRNA levels of Sepp1 in the mouse primary hepatocytes. The cells were treated with palmitate (36 h), insulin (24 h), LPI (12 h) and AKTi (2 h) as indicated following by a quantitative RT-PCR analysis ( n = 3). ( I , J ) Mouse primary hepatocytes were treated by PA (36 h) and ML-193 (6 h) prior to the Sepp1 mRNA ( I ) and SELENOP protein assay ( J ). n = 5 each group. For all: Data are represented as mean ± SEM. Statistical analysis was performed by unpaired two-tailed Student’s t test for ( A ), by two-way ANOVA followed by Tukey’s test for ( B , C , G ), by one-way ANOVA followed by Tukey’s test for ( E , F , H – J ). .

Article Snippet: In order to ascertain the impact of LPI on primary hepatocytes, hepatocytes were treated for 12 h with 5 μM of LPI (Avanti Polar Lipids, #850091 P) and/or 10 μM ML-193 (MCE, #HY-110125) for 6 h. To observe the regulation on Sepp1 expression, primary hepatocytes were treated with 10 nM insulin for 24 h and 5 μM LPI for 12 h with or without 2 μM AKTi (MCE, # HY-10355) for 2 h.

Techniques: Expressing, Plasmid Preparation, Control, Infection, Real-time Polymerase Chain Reaction, Western Blot, Phospho-proteomics, shRNA, Isolation, Quantitative RT-PCR, Two Tailed Test