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Microarray of PBMC from patients with decompensated cirrhosis (AD) and ACLF stimulated with CpG-DNA and treated with human serum albumin (HSA)

ABSTRACT: Human serum albumin (HSA) is an emerging treatment for preventing excessive systemic inflammation and organ failure(s) in patients with acutely decompensated (AD) cirrhosis. Here, we investigated the molecular mechanisms underlying the immunomodulatory properties of HSA. Administration of HSA to patients with AD cirrhosis with elevated circulating bacterial DNA (CpG-DNA) was associated with reduced plasma cytokine levels. In isolated leukocytes, HSA abolished CpG-DNA-induced cytokine expression and release independently of its oncotic and scavenging properties. Similar anti-inflammatory effects were observed with recombinant human albumin. HSA exerted widespread changes on the immune cell transcriptome, specifically in genes related to the endosomal compartment involved in cytosolic DNA sensing and type I interferon responses. Flow cytometry and confocal microscopy analyses revealed that HSA was taken up by leukocytes and internalized in vesicles positively stained with EEA1, a marker of early endosomes. Indeed, HSA and CpG-DNA colocalized in endosomes, the compartment where CpG-DNA binds to TLR9, its cognate receptor. Furthermore, HSA also inhibited poly-(I:C)- and LPS-induced IRF3 phosphorylation and TRIF-mediated responses, which are exclusive of endosomal TLR3 and TLR4 signaling, respectively. The immunomodulatory actions of HSA did not compromise leukocyte defensive mechanisms such as phagocytosis, efferocytosis and intracellular ROS production. The in vitro immunomodulatory effects of HSA were confirmed in vivo in analbuminemic humanized FcRn transgenic mice. In conclusion, these findings indicate that HSA internalizes in immune cells and modulates their responses through interaction with endosomal TLR signaling, thus providing a mechanism for the benefits of HSA infusions in patients with cirrhosis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE146462 | GEO | 2023/03/02

REPOSITORIES: GEO

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Project description:Background&aims: Patients with acute decompensation (AD) of cirrhosis progressing to acute-on-chronic liver failure (ACLF) present a systemic hyperinflammatory response associated with increased circulating levels of small-molecule metabolites. To investigate whether these alterations reflect inadequate cell energy output, we assessed mitochondrial morphology and central metabolic pathways with emphasis on the tricarboxylic acid (TCA) cycle in peripheral leukocytes from AD patients with and without ACLF. Methods: The study included samples from AD patients (102 without and 126 with ACLF) along with 41 healthy subjects. Leukocyte mitochondria ultrastructure was visualized by transmission electron microscopy and cytosolic and mitochondrial metabolic fluxes were determined by assessing NADH/FADH 2 production from various substrates. Plasma GDF15 and FGF21 were determined by Luminex and acylcarnitines by LC-MS/MS. Gene expression was analyzed by RNA-seq and PCR-based glucose metabolism profiler array. Results: Mitochondrial ultrastructure in patients with advanced cirrhosis was distinguished by cristae rarefication and swelling. The number of mitochondria per leukocyte was higher in patients, accompanied by a reduction in their size. Increased FGF21 and C:6- and C:8-carnitines predicted mortality whereas GDF15 strongly correlated with a gene set signature related to leukocyte activation. Metabolic flux analyses revealed increased energy production in mononuclear leukocytes from patients with preferential involvement of extra-mitochondrial pathways, supported by upregulated expression of genes encoding enzymes of the glycolytic and pentose phosphate pathways. In ACLF patients, mitochondrial function analysis uncovered two break-points in the TCA cycle at the isocitrate dehydrogenase and succinate dehydrogenase level, which were bridged by anaplerotic reactions involving glutaminolysis and nucleoside metabolism. Conclusions: Our findings provide evidence at the cellular, organelle and biochemical levels that severe mitochondrial dysfunction governs immunometabolism in leukocytes from patients with AD cirrhosis and ACLF.

Dataset Information

Microarray of PBMC from patients with decompensated cirrhosis (AD) and ACLF stimulated with CpG-DNA and treated with human serum albumin (HSA)

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