Hepatic inflammation after burn injury is associated with necroptotic cell death signaling

Burn-induced mitochondrial dysfunction in hepatocytes: The role of methylation-controlled J protein silencing

BACKGROUND

Burn injuries trigger a systemic hyperinflammatory response, leading to multiple organ dysfunction, including significant hepatic damage. The liver plays a crucial role in regulating immune responses and metabolism after burn injuries, making it critical to develop strategies to mitigate hepatic impairment. This study investigates the role of methylation-controlled J protein (MCJ), an inner mitochondrial protein that represses complex I in burn-induced oxidative stress and mitochondrial dysfunction, using an in vitro Alpha Mouse Liver 12 cell model.

METHODS

Alpha Mouse Liver 12 cells were treated with serum from burn-injured mice (SBIM) to simulate burn injury in vitro. Methylation-controlled J protein was silenced using shRNA. Cell viability, apoptosis markers, reactive oxygen species levels, antioxidant response elements, electron transport chain components, and mitochondrial respiration were assessed using various techniques, including Cell Counting Kit-8 assay, Western blotting, MitoSOX Red staining, and Seahorse XF analysis.

RESULTS

Serum from burn-injured mice treatment (10%) for 8 hours reduced Alpha Mouse Liver 12 cell viability to 50% of control levels and increased MCJ expression fivefold. It also significantly upregulated apoptosis markers: cleaved caspase-3 (4-fold), Bax (3.8-fold), and cytosolic cytochrome c (3.5-fold). Methylation-controlled J protein silencing improved cell viability to 85% of control levels and reduced apoptosis markers by 75% to 78%. Serum from burn-injured mice increased reactive oxygen species levels by 3-fold, while MCJ silencing reduced this by 2.5-fold. Antioxidant proteins (NRF2, HO-1, NQO-1, GCLC, catalase) were suppressed by SBIM but upregulated 3.2- to 3.8-fold with MCJ silencing. Serum from burn-injured mice reduced electron transport chain components (NDUFS1, SDHB, MTCO2) by 45% to 65%, which MCJ silencing restored 2.5- to 3-fold. Mitochondrial respiration improved significantly with MCJ silencing: basal respiration (+26%), maximal respiration (+66%), adenosine triphosphate production (+25%), and spare respiratory capacity (+63%).

CONCLUSION

Methylation-controlled J protein plays a critical role in burn-induced hepatocyte damage. Its silencing alleviates SBIM-induced cytotoxicity, oxidative stress, and mitochondrial dysfunction. These findings highlight MCJ as a potential therapeutic target for preserving liver function in burn patients, warranting further in vivo studies to explore its clinical potential.

Hydroxytyrosol Alleviates Acute Liver Injury by Inhibiting the TNF-α/PI3K/AKT Signaling Pathway via Targeting TNF-α Signaling

Acute liver injury (ALI) is an injury to liver tissue caused by viruses, drugs, alcohol, and oxygen deprivation, and is one of the most common and serious clinical disorders. Hydroxytyrosol (HT) is a naturally occurring polyphenolic compound isolated from forsythia and has excellent anti-inflammatory properties. However, the effect and mechanisms of HT in ALI remain unclear. We used the LPS/D-GalN induced experimental ALI mouse model and AML12 cells to reveal the efficacy and potential mechanisms of HT in ALI, and HE staining was used for the evaluation of pathologies. A biochemical assay was used to detect changes in liver function, RNA-seq was conducted to reveal the underlying mechanisms of HT for ALI, and WB, RT-qPCR, and IF were used to assess the effects of HT action. Furthermore, an in vitro ALI model against HT in AML12 cells induced by LPS/D-GalN was used to assess the HT protection mechanism. HT significant alleviated LPS/D-GalN-induced ALI in the mice by suppressing inflammatory. In terms of RNA-seq, HT improved the TNF, ECM-receptor interaction, and PI3K/AKT signaling pathway, and it downregulated the mRNA levels of VCAM-1, CXCL5, TNF-α and IL-6 in the liver. Mechanically, HT alleviated LPS/D-GalN in the mice by targeting TNF-α, thereby inhibiting the TNF-α/PI3K/AKT signaling pathway.

Tranexamic acid reduces inflammation, edema and burn wound conversion in a rodent model

Burn wound conversion is the observed process where superficial partial thickness burns convert into deep partial or full thickness burn injuries. This conversion process often involves surgical excision to achieve timely wound healing. Unfortunately, the pathophysiology of this phenomenon is multifactorial and poorly understood. Thus, a therapeutic intervention that may prevent secondary progression and cell death in burn-injured tissue is desirable. Recent work by our group and others has established that tranexamic acid (TXA) has significant anti-inflammatory properties in addition to its well-known anti-fibrinolytic effects. This study investigates TXA as a novel therapeutic treatment to mitigate burn wound conversion and reduce systemic inflammation. Sprague-Dawley rats were subjected to a hot comb burn contact injury. A subset of animals underwent a similar comb burn with an adjacent 30%TBSA contact injury. The interspaces represent the ischemic zones simulating the zone of stasis. The treatment group received injections of TXA (100 mg/kg) immediately after injury and once daily until euthanasia. Animals were harvested for analyses at 6 h and 7 days after injury. Full-thickness biopsies from the ischemic zones and lung tissue were assessed with established histological techniques. Plasma was collected for measurement of damage associated molecular patterns (DAMPs), and liver samples were used to study inflammatory cytokines expression. Treatment with TXA was associated with reduced burn wound conversion and decreased burn-induced systemic inflammatory response syndrome (SIRS). Lung inflammation and capillary leak were also significantly reduced in TXA treated animals. Future research will elucidate the underlying anti-inflammatory properties of TXA responsible for these findings.

Targeting necroptosis in fibrosis

Necroptosis, a type of programmed cell death that resembles necrosis, is now known to depend on a different molecular mechanism from apoptosis, according to several recent studies. Many efforts have reported the possible influence of necroptosis in human disorders and concluded the crucial role in the pathophysiology of various diseases, including liver diseases, renal injuries, cancers, and others. Fibrosis is the most common end-stage pathological cascade of several chronic inflammatory disorders. In this review, we explain the impact of necroptosis and fibrosis, for which necroptosis has been demonstrated to be a contributing factor. We also go over the inhibitors of necroptosis and how they have been applied to fibrosis models. This review helps to clarify the role of necroptosis in fibrosis and will encourage clinical efforts to target this pathway of programmed cell death.

Transcriptomics, metabolomics, and in-silico drug predictions for liver damage in young and aged burn victims

Burn induces a systemic response affecting multiple organs, including the liver. Since the liver plays a critical role in metabolic, inflammatory, and immune events, a patient with impaired liver often exhibits poor outcomes. The mortality rate after burns in the elderly population is higher than in any other age group, and studies show that the liver of aged animals is more susceptible to injury after burns. Understanding the aged-specific liver response to burns is fundamental to improving health care. Furthermore, no liver-specific therapy exists to treat burn-induced liver damage highlighting a critical gap in burn injury therapeutics. In this study, we analyzed transcriptomics and metabolomics data from the liver of young and aged mice to identify mechanistic pathways and in-silico predict therapeutic targets to prevent or reverse burn-induced liver damage. Our study highlights pathway interactions and master regulators that underlie the differential liver response to burn injury in young and aged animals.

Relationship of zinc level with pathogenetically significant homeostasis disorders in severely burned patients

The aim of the study was to assess the zinc content and identify the relationship between the concentration of this element and changes in the biochemical status of patients and markers of inflammation during burn shock. We examined 23 patients aged 45.3±16.1 years with burns of I-II-III degree, area of 31-80%. The serum concentrations of zinc, albumin, interleukin-6, C-reactive protein (CRP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. The majority of patients (21/23) had severe hypocincemia, correlated with burn area (r=-0.53; p=0.008). A decrease in zinc levels during burn shock was associated with the development of hypoalbuminemia (r=0.52, p=0.01). The association of deviations in ALT and AST activity with changes in zinc concentration was revealed (-0.59<γ<-0.61, 0.008<p<0.009), which may indicate the role of hepatic dysfunction in the development of hypocinkemia. The development of a systemic inflammatory response was revealed. The correlation analysis revealed an association between the zinc and interleukin-6 levels (r=-0.63, p=0.03), as well as zinc and CRP (r=-0.41, p=0.04). From the first days after the injury, zinc deficiency is observed in severely burned patients, which is affected by an inflammatory reaction and hypoalbuminemia. Due to the fact that zinc is one of the key factors in maintaining homeostasis in the body, it is necessary to further study the molecular mechanisms of regulating the level of this trace element in burned patients and to develop ways to correct hypocinkemia that contribute to the effective treatment of burn disease.

Early Transcriptomic Response to Burn Injury: Severe Burns Are Associated With Immune Pathway Shutdown

Burn injury induces a systemic hyperinflammatory response with detrimental side effects. Studies have described the biochemical changes induced by severe burns, but the transcriptome response is not well characterized. The goal of this work is to characterize the blood transcriptome after burn injury. Burn patients presenting to a regional center between 2012 and 2017 were prospectively enrolled. Blood was collected on admission and at predetermined time points (hours 2, 4, 8, 12, and 24). RNA was isolated and transcript levels were measured with a gene expression microarray. To identify differentially regulated genes (false-discovery rate ≤0.1) by burn injury severity, patients were grouped by TBSA above or below 20% and statistically enriched pathways were identified. Sixty-eight patients were analyzed, most patients were male with a median age of 41 (interquartile range, 30.5-58.5) years, and TBSA of 20% (11%-34%). Thirty-five patients had % TBSA injury ≥20%, and this group experienced greater mortality (26% vs 3%, P = .008). Comparative analysis of genes from patients with </≥20% TBSA revealed 1505, 613, 380, 63, 1357, and 954 differentially expressed genes at hours 0, 2, 4, 8, 12, and 24, respectively. Pathway analysis revealed an initial up-regulation in several immune/inflammatory pathways within the ≥20% TBSA groups followed by shutdown. Severe burn injury is associated with an early proinflammatory immune response followed by shutdown of these pathways. Examination of the immunoinflammatory response to burn injury through differential gene regulation and associated immune pathways by injury severity may identify mechanistic targets for future intervention.

Dexmedetomidine protects against burn-induced intestinal barrier injury via the MLCK/p-MLC signalling pathway

BACKGROUND

Evidence suggests that sedative dexmedetomidine can prevent intestinal dysfunction. However, the specific mechanisms of its protective effects against burn-induced intestinal barrier injury remain unclear. We aimed to explore the possible positive effects of dexmedetomidine on burn-induced intestinal barrier injury and the effects the myosin light chain kinase (MLCK)/phosphorylated myosin light chain (p-MLC) signalling pathway in an experimental model of burn injury.

METHODS

In this study, the plasma concentration of fluorescein isothiocyanate-labelled dextran (FITC-dextran) was measured. Histological changes were evaluated using haematoxylin and eosin (HE) staining. Tight junction proteins were evaluated by western blot and immunofluorescence analyses to assess the structural integrity of intestinal tight junctions. The level of inflammation was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results shows that the increase in intestinal permeability caused by burn injury is accompanied by histological damage to the intestine, decreases in the expression of the tight junction proteins Zonula Occludens-1 (ZO-1) and Occludin, increases in inflammatory cytokine levels and elevation of both MLCK protein expression and MLC phosphorylation. After dexmedetomidine treatment, the burn-induced changes were ameliorated.

CONCLUSIONS

In conclusion, dexmedetomidine exerted an anti-inflammatory effect and protected tight junction complexes against burn‑induced intestinal barrier damage by inhibiting the MLCK/p-MLC signalling pathways.