Role of Elevated Fibrinogen in Burn-Induced Mitochondrial Dysfunction: Protective Effects of Glycyrrhizin

Fibrinogen in mice cerebral microvessels induces blood-brain barrier dysregulation with aging via a dynamin-related protein 1-dependent pathway

We previously reported evidence that oxidative stress during aging leads to adverse protein profile changes of brain cortical microvessels (MVs: end arterioles, capillaries, and venules) that affect mRNA/protein stability, basement membrane integrity, and ATP synthesis capacity in mice. As an extension of our previous study, we also found that proteins which comprise the blood-brain barrier (BBB) and regulate mitochondrial quality control were also significantly decreased in the mice's cortical MVs with aging. Interestingly, the neuroinflammatory protein fibrinogen (Fgn) was increased in mice brain MVs, which corresponds with clinical reports indicating that the plasma Fgn concentration increased progressively with aging. In this study, protein-protein interaction network analysis indicated that high expression of Fgn is linked with downregulated expression of both BBB- and mitochondrial fission/fusion-related proteins in mice cortical MVs with aging. To investigate the mechanism of Fgn action, we observed that 2 mg/mL or higher concentration of human plasma Fgn changed cell morphology, induced cytotoxicity, and increased BBB permeability in primary human brain microvascular endothelial cells (HBMECs). The BBB tight junction proteins were significantly decreased with increasing concentration of human plasma Fgn in primary HBMECs. Similarly, the expression of phosphorylated dynamin-related protein 1 (pDRP1) and other mitochondrial fission/fusion-related proteins were also significantly reduced in Fgn-treated HBMECs. Interestingly, DRP1 knockdown by shRNA(h) resulted in the reduction of both BBB- and mitochondrial fission/fusion-related proteins in HBMECs. Our results suggest that elevated Fgn downregulates DRP1, leading to mitochondrial-dependent endothelial and BBB dysfunction in the brain microvasculature.

Pathogenic Role of Fibrinogen in the Neuropathology of Multiple Sclerosis: A Tale of Sorrows and Fears

Multiple sclerosis (MS) is an autoimmune demyelinating neurodegenerative disease of the central nervous system (CNS) due to injury of the myelin sheath by immune cells. The clotting factor fibrinogen is involved in the pathogenesis of MS by triggering microglia and the progress of neuroinflammation. Fibrinogen level is correlated with MS severity; consequently, inhibition of the fibrinogen cascade may reduce MS neuropathology. Thus, this review aimed to clarify the potential role of fibrinogen in the pathogenesis of MS and how targeting of fibrinogen affects MS neuropathology. Accumulation of fibrinogen in the CNS may occur independently or due to disruption of blood-brain barrier (BBB) integrity in MS. Fibrinogen acts as transduction and increases microglia activation which induces the progression of inflammation, oxidative stress, and neuronal injury. Besides, brain fibrinogen impairs the remyelination process by inhibiting the differentiation of oligodendrocyte precursor cells. These findings proposed that fibrinogen is associated with MS neuropathology through interruption of BBB integrity, induction of neuroinflammation, and demyelination with inhibition of the remyelination process by suppressing oligodendrocytes. Therefore, targeting of fibrinogen and/or CD11b/CD18 receptors by metformin and statins might decrease MS neuropathology. In conclusion, inhibiting the expression of CD11b/CD18 receptors by metformin and statins may decrease the pro-inflammatory effect of fibrinogen on microglia which is involved in the progression of MS.

Mitochondrial dysfunction and mitophagy: crucial players in burn trauma and wound healing

Burn injuries are a significant cause of death worldwide, leading to systemic inflammation, multiple organ failure and sepsis. The progression of burn injury is explicitly correlated with mitochondrial homeostasis, which is disrupted by the hyperinflammation induced by burn injury, leading to mitochondrial dysfunction and cell death. Mitophagy plays a crucial role in maintaining cellular homeostasis by selectively removing damaged mitochondria. A growing body of evidence from various disease models suggest that pharmacological interventions targeting mitophagy could be a promising therapeutic strategy. Recent studies have shown that mitophagy plays a crucial role in wound healing and burn injury. Furthermore, chemicals targeting mitophagy have also been shown to improve wound recovery, highlighting the potential for novel therapeutic strategies based on an in-depth exploration of the molecular mechanisms regulating mitophagy and its association with skin wound healing.

Assessment of mechanisms of infectious pneumonia based on expression of fibrinogen, procalcitonin, high-sensitivity C-reactive protein expression, T helper 17 cells, regulatory T cells interleukin-10, and interleukin-17

BACKGROUND

Infectious pneumonia is one of the important causes of neonatal death that can lead to the imbalance of T helper 17 cells (Th17) and T regulatory T cells (Treg) cells. The correlation between plasma fibrinogen (FIB), procalcitonin (PCT), C-reactive protein (CRP) and Th17/Treg-IL-10/IL-17 axis balance and their specific role in the occurrence and development of infectious pneumonia are not completely clear.

METHODS

Thirty specific-pathogen free Sprague Dawley (SD) rats were randomly divided into a control group for comparison and IPN model group. After the establishment of infectious pneumonia model, levels of FIB, PCT, hs-CRP, IL-10, and IL-17 in the serum of the two groups were measured using enzyme linked immunosorbent assay (ELISA), the pathological changes of lung tissue were observed using hematoxylin and eosin (HE) staining, the number of Treg and Th17 cells and the ratio of Th17/Treg in serum were detected using flow cytometry, and the levels of retinoic acid-related orphan receptor γt and forkhead box P3 (FOXP3) in lung tissue were detected using reverse transcription polymerase chain reaction (RT-PCR) and western blot.

RESULTS

The results showed that the serum levels of FIB, PCT, hs-CRP, Th17 cell number, Th17/Treg ratio, left lung dry and wet weight, lung tissue wet/dry ratio, lung pathology score and IL-17 level in the model group were significantly higher than those in the control group, while the number of Treg cells and the level of IL-10 in the model group were significantly lower than those in the control group. In addition, the expression of Foxp3mRNA and protein in lung tissue of model group decreased significantly, while the expression level of ROR- γ t mRNA and protein increased.

CONCLUSIONS

In infectious pneumonia, the expression levels of FIB, PCT and hs-CRP are up-regulated, and Th17 cells are activated, Treg cells are inhibited, proinflammatory cytokine IL-17 expression is up-regulated, anti-inflammatory cytokine IL-10 expression is down-regulated, resulting in increased inflammatory response, thus promoting the occurrence and development of infectious pneumonia.

Damage-Associated Molecular Patterns and the Systemic Immune Consequences of Severe Thermal Injury

Thermal injury is often associated with a proinflammatory state resulting in serious complications. After a burn, the innate immune system is activated with subsequent immune cell infiltration and cytokine production. Although the innate immune response is typically beneficial, an excessive activation leads to cytokine storms, multiple organ failure, and even death. This overwhelming immune response is regulated by damage-associated molecular patterns (DAMPs). DAMPs are endogenous molecules that are actively secreted by immune cells or passively released by dead or dying cells that can bind to pathogen recognition receptors in immune and nonimmune cells. Recent studies involving animal models along with human studies have drawn great attention to the possible pathological role of DAMPs as an immune consequence of thermal injury. In this review, we outline DAMPs and their function in thermal injury, shedding light on the mechanism of sterile inflammation during tissue injury and identifying new immune targets for treating thermal injury.

Nuclear-Mitochondrial interactions influence susceptibility to HIV-associated neurocognitive impairment

HIV-associated neurocognitive impairment (NCI) is a term established to capture a wide spectrum of HIV related neurocognitive deficits ranging in severity from asymptomatic to dementia. The genetic underpinnings of this complex phenotype are incompletely understood. Mitochondrial function has long been thought to play a role in neurodegeneration, along with iron metabolism and transport. In this work, we aimed to characterize the interplay of mitochondrial DNA (mtDNA) haplogroup and nuclear genetic associations to NCI phenotypes in the CHARTER cohort, encompassing 1025 individuals of European-descent, African-descent, or admixed Hispanic. We first employed a polygenic modeling approach to investigate the global effect of previous marginally associated nuclear SNPs, and to examine how the polygenic effect of these SNPs is influenced by mtDNA haplogroups. We see evidence of a significant interaction between nuclear SNPs en masse and mtDNA haplogroups within European-descent and African-descent individuals. Subsequently, we performed an analysis of each SNP by mtDNA haplogroup, and detected significant interactions between two nuclear SNPs (rs17160128 and rs12460243) and European haplogroups. These findings, which require validation in larger cohorts, indicate a potential new role for nuclear-mitochondrial DNA interactions in susceptibility to NCI and shed light onto the pathophysiology of this neurocognitive phenotype.

Burn Serum Stimulates Myoblast Cell Death Associated with IL-6-Induced Mitochondrial Fragmentation

BACKGROUND

Burn patients suffer muscle mass loss associated with hyperinflammation and hypercatabolism. The mitochondria are affected by this metabolic alteration. Mitochondrial fission activates a caspase cascade that ultimately leads to cell death. We postulate that burn-induced muscle loss is associated with increased mitochondrial fission and subsequent functional impairment. Further, we investigated whether the cytokine IL-6 plays a major role in mitochondrial fission-associated cell death after burn.

METHODS

Murine myoblast C2C12 cells were treated with 10% serum isolated either from control rats or 40% total body surface area burned rats. Mitochondria were labeled with MitoTracker Green for live cell images. Mitochondrial function was assessed with an Enzo Mito-ID membrane potential cytotoxicity kit. Protein signals were detected by Western blot analysis. Moreover, recombinant IL-6 was applied to stimulate C2C12 to differentiate the role of cytokine IL-6; lastly, we treated burn serum-stimulated cells with IL-6 antibodies.

RESULTS

Caspase 3 activity increased in C2C12 cells with burn serum stimulation, suggesting increased cell death in skeletal muscle after burn. Mitochondrial morphology shortened and mitochondrial membrane potential decreased in cells treated with burn serum. Western blot data showed that mitofusion-1 expression significantly decreased in burn serum-treated cells, supporting the morphologic observation of mitochondrial fission. Mitochondrial fragmentation increased with IL-6 stimulation, and IL-6 antibody decreased caspase 3 activity and mitochondrial membrane potential improved in burn serum-stimulated cells.

CONCLUSION

Burn serum caused muscle cell death associated with increased mitochondrial fission and functional impairment. This alteration was alleviated with IL-6 antibody treatment, suggesting the cytokine plays a role in mitochondrial changes in muscle after systemic injury.

The association of plasma fibrinogen with clinicopathological features and prognosis in esophageal cancer patients

Background

Numerous studies have shown that plasma fibrinogen was linked to esophageal cancer (EC) risk. However, the clinical significance of plasma fibrinogen in EC patients remain unclear and need to be further clarified.

Results

A total of 2865 patients with EC from 11 published studies were included in this meta-analysis. The prognostic and clinical relevance of plasma fibrinogen were evaluated in EC patients. Statistical significance of the pooled hazard ratio (HR) was found for overall survival (OS), disease free survival (DFS) and recurrence-free survival (RFS) in EC. Subgroup analyses for OS were also performed to confirm the prognostic value of plasma fibrinogen. Additionally, the overall results indicated that elevated plasma fibrinogen was significantly associated with tumor invasion, lymph node metastasis (LNM) and clinical stage.

Materials and Methods

A comprehensive literature retrieval was performed in PubMed, Embase, Cochrane database, Web of science and Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases to identify relevant studies published prior to April 15, 2017.

Conclusions

Elevated plasma fibrinogen could be served as a promising biomarker for predicting a poor prognosis and unfavorable clinicopathologic features for EC.

Burn-induced muscle metabolic derangements and mitochondrial dysfunction are associated with activation of HIF-1α and mTORC1: Role of protein farnesylation

Metabolic derangements are a clinically significant complication of major trauma (e.g., burn injury) and include various aspects of metabolism, such as insulin resistance, muscle wasting, mitochondrial dysfunction and hyperlactatemia. Nonetheless, the molecular pathogenesis and the relation between these diverse metabolic alterations are poorly understood. We have previously shown that burn increases farnesyltransferase (FTase) expression and protein farnesylation and that FTase inhibitor (FTI) prevents burn-induced hyperlactatemia, insulin resistance, and increased proteolysis in mouse skeletal muscle. In this study, we found that burn injury activated mTORC1 and hypoxia-inducible factor (HIF)-1α, which paralleled dysfunction, morphological alterations (i.e., enlargement, partial loss of cristae structure) and impairment of respiratory supercomplex assembly of the mitochondria, and ER stress. FTI reversed or ameliorated all of these alterations in burned mice. These findings indicate that these burn-induced changes, which encompass various aspects of metabolism, may be linked to one another and require protein farnesylation. Our results provide evidence of involvement of the mTORC1-HIF-1α pathway in burn-induced metabolic derangements. Our study identifies protein farnesylation as a potential hub of the signaling network affecting multiple aspects of metabolic alterations after burn injury and as a novel potential molecular target to improve the clinical outcome of severely burned patients.