AMPK x Aldolases

Acute lung injury is a critical condition that severely disrupts pulmonary gas exchange, potentially causing respiratory and multiple organ failure.This condition is usually caused by various factors such as infection, which poses a serious threat to the health and life of patients and requires timely diagnosis and treatment. As a new AMPK (AMP-activated protein kinase) activator, "Aldometanib" specifically activates lysosomal AMPK by blocking the binding of aldolase to fructose-1,6-diphosphate (FBP), thereby mimicking the effects of starvation and caloric restriction. AMPK is crucial for regulating cellular metabolism and maintaining energy balance in the body. This study assessed aldometanib's impact on lung fibroblasts injury induced by Lipopolysaccharide (LPS). Therefore, we established a cell injury model of LPS-treated lung fibroblasts. The experimental results showed that aldometanib could effectively improve the proliferation inhibition of lung fibroblasts caused by LPS by evaluating cell proliferation marker molecules. Subsequent research demonstrated that aldometanib effectively mitigates inflammation and oxidative stress damage induced by LPS. We also found that aldometanib can inhibit NLRP3-mediated pyroptosis. Mechanistic study found that Aldometanib mitigates LPS-induced lung fibroblasts injury through activation of the AMPK signaling pathway. This finding introduces a novel pharmacological target for treating pulmonary inflammatory diseases and expands the potential use of AMPK activators in lung health.

The labe free proteomics technology and 4D labe free phosphorylation proteomics technology was used to systematically analyse the protein expression regulatory mechanisms of muscle tenderness. 59 differentially expressed proteins were screened by proteomic data analysis. Phosphorylated proteomic analysis showed 681 modified peptide levels were changed, of which 235 modified peptide levels corresponded to 132 proteins up-regulated and 446 modified peptide levels corresponded to 253 proteins down-regulated. Then, the two-omics analysis further predicted that the regulatory mechanism of tenderness was mainly based on glycolysis, regulating mitochondrial autophagy, apoptosis, AMPK and HIF-1 signaling pathway to regulate muscle tenderness, which was specifically manifested in the modulation of Ca²⁺ release to promote the degradation of myofibrillar fibrillar proteins by the relevant proteins, shortening of post-slaughter muscle glycolysis and reducing the degree of muscle glycolysis. Which was verified by WB, P53, ENO5, ALDOA, ENDOG and PINK1 were identified as potential factors for tenderness regulation.

Aldolases (ALDO) are sensors that regulate AMPK via binding to fructose 1,6-biphosphate (FBP), an intermediate of glucose and fructose metabolism. Fructose consumption is linked to metabolic dysfunction-associated steatotic liver disease (MASLD) progression but whether ALDO-AMPK signaling is involved is unknown. Methionine adenosyltransferase alpha 1 (Mat1a) knockout (KO) mice have low hepatic S-adenosylmethionine (SAMe) level and spontaneously develop steatohepatitis. ALDOB methylation has not been reported and here we investigated whether SAMe level regulates ALDOB and ALDOB-AMPK signaling and whether fructose feeding accelerates MASLD progression by disrupting ALDOB-AMPK signaling.

Mass spectrometry identified ALDOB methylation sites and recombinant in vitro approaches assessed how methylation at those sites affects ALDOB oligomerization and activity. Primary hepatocytes cultured with high/low glucose and/or fructose and wild type (WT) and Mat1a KO mice fed with a high-fructose diet examined AMPK-ALDOB signaling and MASLD progression.

In Mat1a KO livers ALDOB R173 is hypomethylated while ALDOB activity is enhanced. Recombinant ALDOB is methylated at R173 and R304 by protein arginine methyltransferase 1. Low hepatic SAMe level results in hypomethylated ALDOB, which favors the tetrameric form that has higher enzymatic activity, and higher capacity to signal to activate AMPK. Fructose, independently of glucose levels, inhibited AMPK activity and induced lipid accumulation in hepatocytes. Mat1a KO mice have hyperactivated AMPK and fructose feeding inhibits it, enhancing the accumulation of fat in the liver and the progression of MASLD.

Hepatic SAMe levels regulate ALDOB oligomeric state and enzymatic activity impacting on AMPK signaling and fructose-induced MASLD progression.