Soybean polyenylphosphatidylcholine (PPC) is beneficial in liver and extrahepatic tissue injury: An update in experimental research

Raman imaging investigation of hepatic LX-2 cell reversion under different lipidic treatments

Liver fibrosis resulting from chronic liver injury is characterized by increased extracellular matrix deposition and inflammation, which leads to excessive scar tissue formation. Targeting activated hepatic stellate cells (HSCs), which are the primary drivers of fibrogenesis, stands out as one of the most compelling therapeutic approaches in this regard. In a healthy liver, HSCs remain quiescent and store vitamin A in cytoplasmic lipid droplets. As a consequence of HSC activation and transdifferentiation to a proliferative myofibroblast-like state upon fibrotic stimuli, the distinctive phenotypic feature of the lipid droplets gets lost. While the reversal of activated HSCs is feasible, understanding the quiescent-like state following injury resolution is crucial for effective fibrosis treatment. This study explores the induced quiescent-like state of naïve immortalized human hepatic stellate (LX-2) cells when treated with soybean phospholipid that contains 75% phosphatidylcholine (S80). The lipid profile of the newly formed lipid droplets was analyzed using Raman imaging, which is a label-free technique well-suited for lipidomics. Results indicate the presence of distinct lipid profiles despite maintaining a quiescent-like state, suggesting that diverse mechanisms govern the active-to-inactive state transition. Additionally, our findings support the fact that each hepatic cell state is composed of heterogeneous subpopulations. This emphasizes the complexity of liver fibrosis and highlights the need for a comprehensive understanding of cellular states to develop targeted therapies.

Lipopolysaccharide, arbiter of the gut-liver axis, modulates hepatic cell pathophysiology in alcoholism

Over the last four decades, clinical research and experimental studies have established that lipopolysaccharide (LPS)-a component of the outer membrane of gram-negative bacteria-is a potent hepatotoxic molecule in humans and animals. Alcohol abuse is commonly associated with LPS endotoxemia. This review highlights LPS molecular structures and modes of release from bacteria, plasma LPS concentrations, induction of microbiota dysbiosis, disruption of gut epithelial barrier, and translocation of LPS into the portal circulation impacting the pathophysiology of hepatic cells via the gut-liver axis. We describe and illustrate the portal vein circulation and its distributaries draining the gastrointestinal tract. We also elaborate on the gut-liver axis coupled with enterohepatic circulation that represents a bidirectional communication between the gut and liver. The review also updates the data on how circulating LPS is cleared in a coordinated effort between Kupffer cells, hepatocytes, and liver sinusoidal endothelial cells. Significantly, the article reviews and updates the modes/mechanisms of action by which LPS mediates the diverse pathophysiology of Kupffer cells, hepatocytes, sinusoidal endothelial cells, and hepatic stellate cells primarily in association with alcohol consumption. Specifically, we review the intricate linkages between ethanol, microbiota dysbiosis, LPS production, gut-liver axis, and pathophysiology of various hepatic cells. The maintenance of the gut barrier structural and functional integrity and microbiome homeostasis is essential in mitigating alcoholic liver disease and improving liver health.

Plasmalogens Reversed Oxidative Stress and Inflammatory Response Exacerbated by Damage to Cell Membrane Properties in Acute Liver Injury

BACKGROUND

In acute liver injury (ALI), cell membrane damage could induce an inflammatory response and oxidative stress. As a membrane glycerophospholipid, plasmalogens (PLS) are crucial in regulating the cell membrane properties and exhibit beneficial effects in various liver diseases. However, the specific regulatory effects of PLS in the ALI remain unknown.

METHODS

We utilized CCl4 to induce ALI in AML12 hepatocytes and C57BL/6J mice and examined oxidative stress indicators and inflammatory cytokine levels. Our study further validated the effect of PLS on cell membrane integrity by Lactate Dehydrogenase (LDH) release assay and Dil/Calcein assay, and molecular dynamics (MD) simulations were employed to elucidate the molecular mechanisms by which PLS affected cell membranes.

RESULTS

PLS attenuated hepatocyte damage both in vivo and in vitro. Moreover, PLS increased levels of SOD, GSH, and CAT and inhibited the production of malondialdehyde. PLS succeeded in decreasing proinflammatory cytokines (TNF-α, IL-1β, and IL-6) while increasing anti-inflammatory cytokines (IL-10). Furthermore, PLS effectively maintained the cell membrane integrity. The MD simulations well explained the molecular mechanisms: a high level of PLS modulated the cell membrane properties, enabling them to be more flexible, elastic, and less prone to rupture.

CONCLUSIONS

Our study illustrated the effect and molecular mechanisms of PLS against ALI, potentially broadening its application in liver diseases.

TM6SF2 E167K variant decreases PNPLA3-mediated PUFA transfer to promote hepatic steatosis and injury in MASLD

BACKGROUNDS/AIMS

Transmembrane 6 superfamily member 2 (TM6SF2) E167K variant is closely associated with the occurrence and development of metabolic dysfunction-associated steatotic liver disease (MASLD). However, the role and mechanism of TM6SF2 E167K variant during MASLD progression are not yet fully understood.

METHODS

The Tm6sf2167K knock-in (KI) mice were subjected to high-fat diet (HFD). Hepatic lipid levels of Tm6sf2167K KI mice were detected by lipidomics analysis. Thin-layer chromatography (TLC) was used to measure the newly synthesized triglyceride (TG) and phosphatidylcholine (PC).

RESULTS

The TM6SF2 E167K variant significantly aggravated hepatic steatosis and injury in HFD-induced mice. Decreased polyunsaturated PC level and increased polyunsaturated TG level were found in liver tissue of HFD-induced Tm6sf2167K KI mice. Mechanistic studies demonstrated that the TM6SF2 E167K variant increased the interaction between TM6SF2 and PNPLA3, and impaired PNPLA3-mediated transfer of polyunsaturated fatty acids (PUFAs) from TG to PC. The TM6SF2 E167K variant increased the level of fatty acid-induced malondialdehyde and reactive oxygen species, and decreased fatty acid-downregulated cell membrane fluidity. Additionally, the TM6SF2 E167K variant decreased the level of hepatic PC containing C18:3, and dietary supplementation of PC containing C18:3 significantly attenuated the TM6SF2 E167K-induced hepatic steatosis and injury in HFD-fed mice.

CONCLUSION

The TM6SF2 E167K variant could promote its interaction with PNPLA3 and inhibit PNPLA3-mediated transfer of PUFAs from TG to PC, resulting in the hepatic steatosis and injury during MASLD progression. PC containing C18:3 could act as a potential therapeutic supplement for MASLD patients carrying the TM6SF2 E167K variant.

Ameliorative effect and mechanism of ursodeoxycholic acid on hydrogen peroxide-induced hepatocyte injury

To assess the ameliorative effect of ursodeoxycholic acid (UDCA) on hydrogen peroxide (H2O2)-induced hepatocyte injury. In our in vivo experiments, we modelled hyperlipidemia in ApoE-/- mice subjected to a 3-month high-fat diet and found that HE staining of the liver showed severe liver injury and excessive H2O2 was detected in the serum. We modelled oxidative stress injury in L02 cells by H2O2 in vitro and analyzed the levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and related genes. UDCA significantly improved the level of oxidative stress in H2O2-injured L02 cells (P < 0.05). In addition, UDCA improved the transcription levels of inflammation and oxidative stress-related genes (P < 0.05), showing anti-inflammatory and anti-oxidative stress effects. UDCA has a protective effect on H2O2-damaged L02 cells, which lays a theoretical foundation for its application development.