Abstract Neurokine Sam2 deficiency is associated with behavioral abnormalities including heightened anxiety and fear responses across evolutionarily conserved model organisms. Here, we employed an integrated proteomics and metabolomics approach using liquid chromatography-mass spectrometry (LC-MS) to elucidate molecular signatures associated with autism spectrum disorder (ASD) in Sam2 knockout mice. Comparative analysis of blood plasma samples from Sam2 knockout and wild-type mice revealed substantial alterations in both proteomic and metabolomic profiles. Proteomic analysis identified 68 differentially expressed proteins (comprising 102 peptides), with notable upregulation of complement component C1qc and downregulation of apolipoprotein A1 (Apoa1), implicating dysregulation of complement cascade pathways. Metabolomic profiling uncovered 15 significantly altered metabolites: nine upregulated species including D-glucuronic acid and 5,10-Methylenetetrahydrofolate, and six downregulated metabolites including folinic acid and acetate. Integrative pathway analysis revealed perturbations in glycolysis/gluconeogenesis and glycerophospholipid metabolism, providing mechanistic insights into the molecular consequences of Sam2 deficiency. These findings identify potential biomarkers for anxiety-related disorders and ASD while advancing our understanding of the complex interplay between genetic alterations and proteomic-metabolomic networks in neurodevelopmental conditions. Our results establish a foundation for developing targeted therapeutic interventions and highlight the utility of multi-omics approaches in dissecting the molecular basis of behavioral disorders.

ARHGEF3 emerges as a pivotal regulator of adipocyte dynamics by coordinating YAP-RhoA signaling and enhancing PPARγ activity. These findings offer novel therapeutic insights for addressing obesity and related metabolic disorders.

Hepatic endoplasmic reticulum (ER) stress is implicated in the development of steatosis and its progression to nonalcoholic steatohepatitis (NASH). The ER in the liver can sustain metabolic function by activating defense mechanisms that delay or prevent the progression of nonalcoholic fatty liver disease (NAFLD). However, the precise mechanisms by which the ER stress response protects against NAFLD remain largely unknown. Recently, activin E has been linked to metabolic diseases such as insulin resistance and NAFLD. However, the physiological conditions and regulatory mechanisms driving hepatic Inhbe expression (which encodes activin E) as well as the metabolic role of activin E in NAFLD require further investigation. Here we found that hepatic Inhbe expression increased under prolonged fasting and ER stress conditions, which was mediated by ATF4, as determined by promoter analysis in a mouse model. Consistently, a positive correlation between INHBE and ATF4 expression levels in relation to NAFLD status was confirmed using public human NAFLD datasets. To investigate the role of activin E in hepatic steatosis, we assessed the fluxes of the lipid metabolism in an Inhbe-knockout mouse model. These mice displayed a lean phenotype but developed severe hepatic steatosis under a high-fat diet. The deficiency of Inhbe resulted in increased lipolysis in adipose tissue, leading to increased fatty acid influx into the liver. Conversely, hepatic overexpression of Inhbe ameliorated hepatic steatosis by suppressing lipolysis in adipose tissue through ALK7-Smad signaling. In conclusion, activin E serves as a regulatory hepatokine that prevents fatty acid influx into the liver, thereby protecting against NAFLD.

PURPOSE: Supplementation with essential amino acids (EAAs) has the potential to improve endurance capacity and insulin sensitivity, as well as to increase muscle strength and mass when combined with resistance exercise training (RET). However, the underlying mechanisms are currently unknown. METHODS: We assigned male C57/BL6 mice into control (CON), EAA, RET (ladder climbing, 3 times/week), or EAA + RET with the administration of 2H2O over 2 weeks. Mice in EAA and EAA + RET received EAAs twice a day (1.5 g/kg/day). Muscle mass, physical performance (i.e., strength and endurance), and ex vivo contractile properties were determined before and/or after treatments. The rate of myofibrillar or mitochondrial protein synthesis was measured using the 2H2O labeling technique and mass spectrometry, and whole-body insulin sensitivity and glucose metabolism was assessed by using hyperinsulinemic-euglycemic clamp and oral glucose tolerance test after interventions. RESULTS: Here, we found that combined treatment of EAAs and RET showed a significant increase in muscle mass by 10%, accompanied by a 15% increase in muscle fiber cross-sectional area. This increased muscle mass was primarily due to an increase in myofibrillar protein synthesis rate by 16% via activation of the Akt1/mTORC1 pathway. Additionally, EAA supplementation amplified muscle strength gains through RET and led to a synchronous increase in endurance capacity by 35%. It seems that improved physical performance was due primarily to an increase in the rate of mitochondrial protein synthesis and improved neuromuscular junction stability. Finally, these above-mentioned improvements in the EAA + RET were accompanied by enhanced basal insulin sensitivity and glucose metabolism. CONCLUSIONS: Collectively, this study demonstrated that the combined effects of EAA supplementation and RET increase physical performance through enhancements in muscle protein turnover, mitochondrial biogenesis, and NMJ stability with an associated increase in whole-body insulin sensitivity.