Inhibiting DNA Methylation Improves Survival in Severe Sepsis by Regulating NF-κB Pathway

Epigenetic Mechanisms in Sepsis-Associated Acute Kidney Injury

Sepsis, the dysregulated immune response of the host to infections, leads to numerous complications, including multiple organ dysfunction with sepsis-associated acute kidney injury (SA-AKI) being a frequent complication associated with increased risk of mortality and the progression toward chronic kidney disease (CKD). Several mechanisms have been widely investigated in understanding the complex pathophysiology of SA-AKI, including hemodynamic alterations, inflammation, oxidative stress, and direct cellular injury driven by pathogens or cell-derived products (pathogen-associated molecular patterns and damage-associated molecular patterns). Despite advancements in the management of septic patients, the prognosis of SA-AKI patients remains significantly poor and is associated with high in-hospital mortality and adverse long-term outcomes. Therefore, recent research has focused on the early identification of specific SA-AKI endotypes and subphenotypes through epigenetic analysis and the use of potential biomarkers, either alone or in combination with clinical data, to improve prognosis. Epigenetic regulation, such as DNA methylation, histone modifications, and noncoding RNA modulation, is crucial in modulating gene expression in response to stress and renal injury in SA-AKI. At the same time, these modifications are dynamic and reversible processes that can alter gene expression in several pathways implicated in the context of SA-AKI, including inflammation, immune response, and tolerance status. In addition, specific epigenetic modifications may exacerbate renal damage by causing persistent inflammation or cellular metabolic reprogramming, leading to progression toward CKD. This review aims to provide a comprehensive understanding of the epigenetic characteristics that define SA-AKI, also exploring targeted therapies that can improve patient outcomes and limit the chronic progression of this syndrome.

Epigenetic regulation of innate immune dynamics during inflammation

Innate immune cells play essential roles in modulating both immune defense and inflammation by expressing a diverse array of cytokines and inflammatory mediators, phagocytizing pathogens to promote immune clearance, and assisting with the adaptive immune processes through antigen presentation. Rudimentary innate immune "memory" states such as training, tolerance, and exhaustion develop based on the nature, strength, and duration of immune challenge, thereby enabling dynamic transcriptional reprogramming to alter present and future cell behavior. Underlying transcriptional reprogramming are broad changes to the epigenome, or chromatin alterations above the level of DNA sequence. These changes include direct modification of DNA through cytosine methylation as well as indirect modifications through alterations to histones that comprise the protein core of nucleosomes. In this review, we will discuss recent advances in our understanding of how these epigenetic changes influence the dynamic behavior of the innate immune system during both acute and chronic inflammation, as well as how stable changes to the epigenome result in long-term alterations of innate cell behavior related to pathophysiology.

Curcumin can improve spinal cord injury by inhibiting DNA methylation

Spinal cord injury (SCI) is a serious central nervous system disease. Traumatic SCI often causes persistent neurological deficits below the injury level. Epigenetic changes occur after SCI. Studies have shown DNA methylation to be a key player in nerve regeneration and remodeling, and in regulating some pathophysiological characteristics of SCI. Curcumin is a natural polyphenol from turmeric. It has anti-inflammatory, antioxidant, and neuroprotective effects, and can mitigate the cell and tissue damage caused by SCI. This report analyzed the specific functions of DNA methylation in central nervous system diseases, especially traumatic brain injury and SCI. DNA methylation can regulate the level of gene expressions in the central nervous system. Therefore, pharmacological interventions regulating DNA methylation may be promising for SCI.

Persistent sepsis-induced transcriptomic signatures in signaling pathways of peripheral blood leukocytes: A pilot study

Sepsis is a dysregulated immune response to infections that frequently precipitates multiple organ dysfunction and death despite intensive supportive therapy. The aim of the present study was to identify sepsis-induced alterations in the signaling transcriptome of peripheral blood leukocytes that might shed light on the elusive transition from proinflammatory to anti-inflammatory responses and underlie long-term post-sepsis immunosuppression. Peripheral blood leukocytes were collected from subjects (i) with systemic inflammation, (ii) with sepsis in the acute phase and (iii) 6 months after recovery from sepsis, corresponding to progressive stages of the disease. Transcriptomic analysis was performed with the QuantStudio 12K Flex OpenArray Human Signal Transduction Panel analyzing transcripts of 573 genes playing a significant role in signaling. Of them, 145 genes exhibited differential expression in sepsis as compared to systemic inflammation. Pathway analysis revealed enhanced expression levels of genes involved in primary immune responses (proinflammatory cytokines, neutrophil and macrophage activation markers) and signatures characteristic of immunosuppression (increased expression of anti-inflammatory cytokines and proapoptotic genes; diminished expression of T and B cell receptor dependent activating and survival pathways). Importantly, sepsis-induced expression patterns of 39 genes were not normalized by the end of the 6-month follow-up period, indicating expression aberrations persisting long after clinical recovery. Functional analysis of these transcripts revealed downregulation of the antiapoptotic Wnt and mTOR signaling pathways that might explain the post-sepsis immunosuppression commonly seen in sepsis survivors.

Protein modification by short-chain fatty acid metabolites in sepsis: a comprehensive review

Sepsis is a major life-threatening syndrome of organ dysfunction caused by a dysregulated host response due to infection. Dysregulated immunometabolism is fundamental to the onset of sepsis. Particularly, short-chain fatty acids (SCFAs) are gut microbes derived metabolites serving to drive the communication between gut microbes and the immune system, thereby exerting a profound influence on the pathophysiology of sepsis. Protein post-translational modifications (PTMs) have emerged as key players in shaping protein function, offering novel insights into the intricate connections between metabolism and phenotype regulation that characterize sepsis. Accumulating evidence from recent studies suggests that SCFAs can mediate various PTM-dependent mechanisms, modulating protein activity and influencing cellular signaling events in sepsis. This comprehensive review discusses the roles of SCFAs metabolism in sepsis associated inflammatory and immunosuppressive disorders while highlights recent advancements in SCFAs-mediated lysine acylation modifications, such as substrate supplement and enzyme regulation, which may provide new pharmacological targets for the treatment of sepsis.

Role of DNA methylation during recovery from spinal cord injury with and without β2-adrenergic receptor agonism

Daily treatment with the FDA-approved β2-adrenergic receptor agonist formoterol beginning 8 h after severe spinal cord injury (SCI) induces mitochondrial biogenesis and improves recovery in mice. We observed decreased DNA methyltransferase (DNMT) expression, global DNA methylation and methylation of the mitochondrial genes PGC-1α and NDUFS1 in the injury site of formoterol-treated mice 1 DPI, but this effect was lost by 7 DPI. To investigate the role of DNA methylation on recovery post-SCI, injured mice were treated daily with formoterol or vehicle, plus the DNMT inhibitor decitabine (DAC) on days 7-9. While DAC had no apparent effect on formoterol-induced recovery, mice treated with vehicle plus DAC exhibited increased BMS scores compared to vehicle alone beginning 15 DPI, reaching a degree of functional recovery similar to that of formoterol-treated mice by 21 DPI. Furthermore, DAC treatment increased injury site mitochondrial protein expression in vehicle-treated mice to levels comparable to that of formoterol-treated mice. The effect of DNMT inhibition on pain response with and without formoterol was assessed following moderate SCI. While all injured mice not treated with DAC displayed thermal hyperalgesia by 21 DPI, mice treated with formoterol exhibited decreased thermal hyperalgesia compared to vehicle-treated mice by 35 DPI. Injured mice treated with DAC, regardless of formoterol treatment, did not demonstrate thermal hyperalgesia at any time point assessed. Although these data do not suggest enhanced formoterol-induced recovery with DNMT inhibition, our findings indicate the importance of DNA methylation post-SCI and support both DNMT inhibition and formoterol as potential therapeutic avenues.

Shock drives a STAT3 and JunB-mediated coordinated transcriptional and DNA methylation response in the endothelium

Endothelial dysfunction is a crucial factor in promoting organ failure during septic shock. However, the underlying mechanisms are unknown. Here, we show that kidney injury after lipopolysaccharide (LPS) insult leads to strong endothelial transcriptional and epigenetic responses. Furthermore, SOCS3 loss leads to an aggravation of the responses, demonstrating a causal role for the STAT3-SOCS3 signaling axis in the acute endothelial response to LPS. Experiments in cultured endothelial cells demonstrate that IL-6 mediates this response. Furthermore, bioinformatics analysis of in vivo and in vitro transcriptomics and epigenetics suggests a role for STAT, AP1 and interferon regulatory family (IRF) transcription factors. Knockdown of STAT3 or the AP1 member JunB partially prevents the changes in gene expression, demonstrating a role for these transcription factors. In conclusion, endothelial cells respond with a coordinated response that depends on overactivated IL-6 signaling via STAT3, JunB and possibly other transcription factors. Our findings provide evidence for a critical role of IL-6 signaling in regulating shock-induced epigenetic changes and sustained endothelial activation, offering a new therapeutic target to limit vascular dysfunction.

PSTPIP2 is associated with disease severity in patients with pressure ulcer sepsis and has anti-inflammatory effects

BACKGROUND

One of the common adverse reactions in patients with pressure ulcers (PU) is sepsis, which is mainly related to microbial infections caused by pathogenic organisms. The activation of nuclear factor kappa-B (NF-κB) frequently occurs in conjunction with pathogenic microbial infections. Proline-serine-threonine-phosphatase-interacting protein 2 (PSTPIP2) is closely related to inflammatory disorders. The role and mechanism of PSTPIP2 in sepsis because of pressure ulcers is unclear. In this study, we discovered that PSTPIP2 was lowly expressed in peripheral blood of patients with sepsis induced by pressure ulcers.

METHODS

Peripheral blood was collected from 20 patients with sepsis due to pressure ulcers and 10 healthy controls, and the expression of PSTPIP2 in peripheral blood was discovered by polymerase chain reaction and Western blot analysis. Information on the clinical characteristics of patients was summarized, and the expression data of PSTPIP2 were correlated with the patients' acute physiology and chronic health evaluation (APACHE) II score, sequential organ failure assessment (SOFA) score, and C-reactive protein (CRP) and procalcitonin (PCT) scores by Spearman's correlation analysis. One of the main mediators of Gram-negative sepsis is lipopolysaccharide (LPS). In order to establish an in vitro sepsis model, THP-1 cells were treated with LPS, and the cells were transfected with PSTPIP2. Contents of interleukin 6 (IL-6), interleukin 1β (IL-1β), and tumor necrosis factor-α (TNF-α) in each group of cells were detected by enzyme-linked--immunosorbent serologic assay, and NF-κB-related proteins were detected by Western blot analysis.

RESULTS

When compared to healthy controls, the peripheral blood of patients with pressure sepsis had lower PSTPIP2 expression, which had a negative correlation with the APACHE II, SOFA, CRP, and PCT scores. LPS-induced THP-1 cells expressed less PSTPIP2 than the untreated control cells, and PSTPIP2 transfection decreased IL-6, IL-1β, and TNF-α levels and inhibited the activation of NF-κB pathway.

CONCLUSION

PSTPIP2 is associated with disease severity in patients with pressure ulcer sepsis and has anti-inflammatory effects.

Succinate mediates inflammation-induced adrenocortical dysfunction

The hypothalamus-pituitary-adrenal (HPA) axis is activated in response to inflammation leading to increased production of anti-inflammatory glucocorticoids by the adrenal cortex, thereby representing an endogenous feedback loop. However, severe inflammation reduces the responsiveness of the adrenal gland to adrenocorticotropic hormone (ACTH), although the underlying mechanisms are poorly understood. Here, we show by transcriptomic, proteomic, and metabolomic analyses that LPS-induced systemic inflammation triggers profound metabolic changes in steroidogenic adrenocortical cells, including downregulation of the TCA cycle and oxidative phosphorylation, in mice. Inflammation disrupts the TCA cycle at the level of succinate dehydrogenase (SDH), leading to succinate accumulation and disturbed steroidogenesis. Mechanistically, IL-1β reduces SDHB expression through upregulation of DNA methyltransferase 1 (DNMT1) and methylation of the SDHB promoter. Consequently, increased succinate levels impair oxidative phosphorylation and ATP synthesis and enhance ROS production, leading to reduced steroidogenesis. Together, we demonstrate that the IL-1β-DNMT1-SDHB-succinate axis disrupts steroidogenesis. Our findings not only provide a mechanistic explanation for adrenal dysfunction in severe inflammation, but also offer a potential target for therapeutic intervention.

Less Severe Polymicrobial Sepsis in Conditional mgmt-Deleted Mice Using LysM-Cre System, Impacts of DNA Methylation and MGMT Inhibitor in Sepsis

The O6-methylguanine-DNA methyltransferase (MGMT) is a DNA suicide repair enzyme that might be important during sepsis but has never been explored. Then, the proteomic analysis of lipopolysaccharide (LPS)-stimulated wild-type (WT) macrophages increased proteasome proteins and reduced oxidative phosphorylation proteins compared with control, possibly related to cell injury. With LPS stimulation, mgmt null (mgmt^flox/flox; LysM-Cre^cre/-) macrophages demonstrated less profound inflammation; supernatant cytokines (TNF-α, IL-6, and IL-10) and pro-inflammatory genes (iNOS and IL-1β), with higher DNA break (phosphohistone H2AX) and cell-free DNA, but not malondialdehyde (the oxidative stress), compared with the littermate control (mgmt^flox/flox; LysM-Cre^-/-). In parallel, mgmt null mice (MGMT loss only in the myeloid cells) demonstrated less severe sepsis in the cecal ligation and puncture (CLP) model (with antibiotics), as indicated by survival and other parameters compared with sepsis in the littermate control. The mgmt null protective effect was lost in CLP mice without antibiotics, highlighting the importance of microbial control during sepsis immune modulation. However, an MGMT inhibitor in CLP with antibiotics in WT mice attenuated serum cytokines but not mortality, requiring further studies. In conclusion, an absence of mgmt in macrophages resulted in less severe CLP sepsis, implying a possible influence of guanine DNA methylation and repair in macrophages during sepsis.

Less Severe Lipopolysaccharide-Induced Inflammation in Conditional mgmt-Deleted Mice with LysM-Cre System: The Loss of DNA Repair in Macrophages

Despite the known influence of DNA methylation from lipopolysaccharide (LPS) activation, data on the O6-methylguanine-DNA methyltransferase (MGMT, a DNA suicide repair enzyme) in macrophages is still lacking. The transcriptomic profiling of epigenetic enzymes from wild-type macrophages after single and double LPS stimulation, representing acute inflammation and LPS tolerance, respectively, was performed. Small interfering RNA (siRNA) silencing of mgmt in the macrophage cell line (RAW264.7) and mgmt null (mgmt^flox/flox; LysM-Cre^cre/-) macrophages demonstrated lower secretion of TNF-α and IL-6 and lower expression of pro-inflammatory genes (iNOS and IL-1β) compared with the control. Macrophage injury after a single LPS dose and LPS tolerance was demonstrated by reduced cell viability and increased oxidative stress (dihydroethidium) compared with the activated macrophages from littermate control mice (mgmt^flox/flox; LysM-Cre^-/-). Additionally, a single LPS dose and LPS tolerance also caused mitochondrial toxicity, as indicated by reduced maximal respiratory capacity (extracellular flux analysis) in the macrophages of both mgmt null and control mice. However, LPS upregulated mgmt only in LPS-tolerant macrophages but not after the single LPS stimulation. In mice, the mgmt null group demonstrated lower serum TNF-α, IL-6, and IL-10 than control mice after either single or double LPS stimulation. Suppressed cytokine production resulting from an absence of mgmt in macrophages caused less severe LPS-induced inflammation but might worsen LPS tolerance.

Microvesicle-Mediated Transfer of DNA Methyltransferase Proteins Results in Recipient Cell Immunosuppression

INTRODUCTION

Patients with sepsis exhibit significant, persistent immunologic dysfunction. Evidence supports the hypothesis that epigenetic regulation of key cytokines plays an important role in this dysfunction. In sepsis, circulating microvesicles (MVs) containing elevated levels of DNA methyltransferase (DNMT) mRNA cause gene methylation and silencing in recipient cells. We sought to examine the functional role of MV DNMT proteins in this immunologic dysfunction.

METHODS

In total, 33 patients were enrolled within 24 h of sepsis diagnosis (23 sepsis, 10 critically ill controls). Blood and MVs were collected on days 1, 3, and 5 of sepsis, and protein was isolated from the MVs. Levels of DNMT protein and activity were quantified. MVs were produced in vitro by stimulating naïve monocytes with lipopolysaccharide. Methylation was assessed using bisulfate site-specific qualitative real-time polymerase chain reaction.

RESULTS

The size of MVs in the patients with sepsis decreased from days 1 to 5 compared to the control group. Circulating MVs contained significantly higher levels of DNMT 1 and 3A, protein. We recapitulated the production of these DNMT-containing MVs in vitro by treating monocytes with lipopolysaccharide. We found that exposing naïve monocytes to these MVs resulted in increased promoter methylation of tumor necrosis factor alpha.

CONCLUSIONS

An analysis of the isolated MVs revealed higher levels of DNMT proteins in septic patients than those in nonseptic patients. Exposing naïve monocytes to DNMT-containing MVs produced in vitro resulted in hypermethylation of tumor necrosis factor alpha, a key cytokine implicated in postsepsis immunosuppression. These results suggest that DNMT-containing MVs cause epigenetic changes in recipient cells. This study highlights a novel role for MVs in the immune dysfunction of patients with sepsis.

Personalizing Care for Critically Ill Adults Using Omics: A Concise Review of Potential Clinical Applications

Current guidelines for critically ill patients use broad recommendations to promote uniform protocols for the management of conditions such as acute kidney injury, acute respiratory distress syndrome, and sepsis. Although these guidelines have enabled the substantial improvement of care, mortality for critical illness remains high. Further outcome improvement may require personalizing care for critically ill patients, which involves tailoring management strategies for different patients. However, the current understanding of disease heterogeneity is limited. For critically ill patients, genomics, transcriptomics, proteomics, and metabolomics have illuminated such heterogeneity and unveiled novel biomarkers, giving clinicians new means of diagnosis, prognosis, and monitoring. With further engineering and economic development, omics would then be more accessible and affordable for frontline clinicians. As the knowledge of pathophysiological pathways mature, targeted treatments can then be developed, validated, replicated, and translated into clinical practice.

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 exaggerates multiple organ injury, inflammation, and immune cell imbalance by activating the NF-κB pathway in sepsis

Objective

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) modulates the inflammatory immune response and organ dysfunction, which are closely implicated in sepsis pathogenesis and progression. This study aimed to explore the role of MALT1 in sepsis-induced organ injury, immune cell dysregulation, and inflammatory storms.

Methods

Septic mice were constructed by intraperitoneal injection of lipopolysaccharide, followed by overexpression or knockdown of MALT1 by tail vein injection of the corresponding lentivirus. Mouse naïve CD4⁺ T cells and bone marrow-derived macrophages were treated with MALT1 overexpression/knockdown lentivirus plus lipopolysaccharide.

Results

In the lungs, livers, and kidneys of septic mice, MALT1 overexpression exaggerated their injuries, as shown by hematoxylin and eosin staining (all p < 0.05), elevated cell apoptosis, as reflected by the TUNEL assay and cleaved caspase-3 expression (p < 0.05 in the lungs and kidneys), and promoted macrophage infiltration, as illustrated by CD68 immunofluorescence (p < 0.05 in the lungs and kidneys). Meanwhile, in the blood, MALT1 overexpression reduced T-helper (Th)1/Th2 cells, increased Th17/regulatory T-cell ratios (both p < 0.05), promoted systematic inflammation, as revealed by tumor necrosis factor-α, interleukin-6, interleukin-1β, and C-reactive protein (all p < 0.05), elevated oxidative stress, as shown by nitric oxide (p < 0.05), superoxide dismutase, and malondialdehyde (p < 0.05), and enhanced liver and kidney dysfunction, as revealed by an automatic animal biochemistry analyzer (all p < 0.05 except for aspartate aminotransferase). However, MALT1 knockdown exerted the opposite effect as MALT1 overexpression. Ex vivo experiments revealed that MALT1 overexpression promoted the polarization of M1 macrophages and naïve CD4⁺ T cells toward Th2 and Th17 cells (all p < 0.05), while MALT1 knockdown attenuated these effects (all p < 0.05). Mechanistically, MALT1 positively regulated the nuclear factor-κB (NF-κB) pathway both in vivo and ex vivo (p < 0.05).

Conclusion

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 amplifies multiple organ injury, inflammation, oxidative stress, and imbalance of macrophages and CD4⁺ T cells by activating the NF-κB pathway in sepsis.

Temperature dependent cellular, and epigenetic regulatory mechanisms underlying the antiviral immunity in sevenband grouper to nervous necrosis virus infection

Changes in the thermal optima of fish impacts changes in the physiology and immune response associated with infections. The present study showed that at suboptimal temperatures (17 °C), the host tries to evade viral infection by downregulating the inflammatory response through enhanced neuronal protection. There was significantly less abundance of IgM + B cells in the 17 °C group compared to that in the 25 °C group. An increased macrophage population (Iba1+) during the survival phase in fish challenged at 25 °C demonstrated inflammation. Optimal temperature challenge activated virus-induced senescence in brain cells, demonstrated with a heterochromatin-associated H3K9me3 histone mark. There was an abundant expression of anti-inflammatory cytokines in the brain of fish at the suboptimal challenge. Besides the cytokines, the expression of BDNF was significantly higher in the suboptimally challenged group, suggesting that its neuronal protection activity following NNV infection is mediated through TGFβ. The suboptimal challenge resulted in H3k9ac displaying transcriptional competency, activation of trained immunity H3K4me3, and enrichment of H3 histone-lysine-4 monomethylation (H3K4me1), resulting in a robust re-stimulatory immune response. The observations from the H4 modifications showed that besides H4K12ac and H4K20m3, all the assayed modifications were significantly higher in suboptimal convalescent fishes. The suboptimally challenged fish acquired more methylation along cytosine residues than the optimally infected fish. Together, these observations suggest that optimal temperature results in an immune priming effect, whereas the protection enabled in suboptimal convalescent fishes is operated through epigenetically controlled trained immune functions.

Identification of potential differentially methylated gene-related biomarkers in endometriosis

Aim: To identify epigenetic alterations of differentially expressed genes and screen out targeted therapeutic drugs in endometriosis. Methods: Based on the Gene Expression Omnibus database and a series of biological information analysis tools, supplemented by validation of clinical samples, aberrant DNA methylation-driven genes and their functions were explored, as well as possible targeted drugs. Results: This study screened out a range of DNA methylation-driven genes that were associated with powerful properties and corresponding pathways. Among them, BDNF and CCL2 were key genes in the development of endometriosis. Four chemical agents have been flagged as potential treatments for endometriosis. Conclusion: These candidate genes and small-molecule agents may be further explored as potential targets and drugs for endometriosis diagnosis and therapy, respectively.

Ascorbic acid and hydrocortisone synergistically inhibit septic organ injury via improving oxidative stress and inhibiting inflammation

BACKGROUND

The current study aimed to investigate the effect of the combination of ascorbic acid (AscA) and hydrocortisone (Hyd) on septic organ injury and its potential mechanism.

METHOD

Sepsis was induced in mice by a single intraperitoneal injection of lipopolysaccharides.

RESULTS

AscA and Hyd combined showed more effective protection of the injured liver and kidney in septic mice by decreasing ALT, AST, BUN and SCr and ameliorating pathological manifestations than Hyd or AscA alone. AscA showed a mild inhibitory effect on the secretion of proinflammatory cytokines (TNF-α, IL-1β and IL-6). However, Hyd showed a weak regulatory effect on septic oxidative stress markers (MDA, SOD and GSH-Px). However, the combination of AscA and Hyd showed a more powerful inhibitory effect on the septic inflammatory response and oxidative stress than Hyd or AscA alone by decreasing TNF-α, IL-1β and IL-6 and regulating MDA, SOD and GSH. In an in vitro study, cotreatment of RAW 264.7 macrophages with Hyd and AscA sharply reduced reactive oxygen species (ROS) generation and synergistically inhibited TNF-α, IL-1β and IL-6 secretion, which could be abolished by additional stimulation with the ROS donor 3-nitropropionic acid (3-NP). As expected, cotreatment of macrophages with Hyd and AscA synergistically inhibited the activation of p38 MAPK and p-p65, and the effect could be reversed by additional stimulation with 3-NP.

CONCLUSIONS

AscA and Hyd synergistically protect the kidney and liver from injury by inhibiting the inflammatory response and oxidative stress. The powerful inhibitory effects of AscA on oxidative stress contribute to the synergistic anti-inflammatory action.

Global DNA hypomethylation and the expression profile of DNA methyltransferase genes in late-onset neonatal sepsis

Aim: Infectious organisms tend to cause DNA methylation changes. Thus, this paper aims to study global DNA methylation and the expression of DNA methyltransferase (DNMT) genes in late-onset neonatal sepsis (LONS). Methods: Global and Alu DNA methylation and expression levels of DNMT were performed using 5mc ELISA, methylation-specific PCR and quantitative real-time-PCR, respectively for LONS and controls. Results: Significant hypomethylation of global DNA and Alu DNA methylation and lower expression of DNMT1 and DNMT3a were observed in LONS compared with controls. Receiver operating characteristic analysis of global and Alu DNA methylation showed good discrimination for the identification of LONS. Conclusion: The hypomethylation of global DNA and Alu elements is evident in neonates with LONS. This may be clinically useful for the prognosis of LONS.

A Novel Cognition of Decitabine: Insights into Immunomodulation and Antiviral Effects

DNA methylation, as one of the major means of epigenesis change, makes a large difference in the spatial structure of chromatin, transposable element activity and, fundamentally, gene transcription. It has been confirmed that DNA methylation is closely related to innate immune responses. Decitabine, the most efficient available DNA methyltransferase inhibitor, has demonstrated exhilarating immune activation and antiviral effects on multiple viruses, including HIV, HBV, HCV, HPV and EHV1. This review considers the role of decitabine in regulating innate immune responses and antiviral ability. Understanding the complex transcriptional and immune regulation of decitabine could help to identify and validate therapeutic methods to reduce pathogen infection-associated morbidity, especially virus infection-induced morbidity and mortality.

Role of Age-Related Changes in DNA Methylation in the Disproportionate Susceptibility and Worse Outcomes of Sepsis in Older Adults

Sepsis, a complex multisystem disorder, is among the top causes of hospitalization and mortality in older adults. However, the mechanisms underlying the disproportionate susceptibility to sepsis and worse outcomes in the elderly are not well understood. Recently, changes in DNA methylation have been shown to be linked to aging processes and age-related diseases. Thus, we postulated that age-related changes in DNA methylation may play a role in the onset and prognosis of sepsis in elderly patients. Here, we performed genome-wide methylation profiling of peripheral blood from patients with sepsis and controls. Among the CpG sites whose methylation changes may contribute to an increase in sepsis susceptibility or mortality, 241 sites that possessed age-related changes in DNA methylation in controls may partly explain the increased risk of sepsis in older adults, and 161 sites whose methylation significantly correlated with age in sepsis group may be the potential mechanisms underlying the worse outcomes of elderly septic patients. Finally, an independent cohort was used to validate our findings. Together, our study demonstrates that age-related changes in DNA methylation may explain in part the disproportionate susceptibility and worse outcomes of sepsis in older adults.

DNA Methyltransferase 3b in Myeloid Cells Does Not Affect the Acute Immune Response in the Airways during Pseudomonas Pneumonia

DNA methyltransferase 3b (Dnmt3b) has been suggested to play a role in the host immune response during bacterial infection. Neutrophils and other myeloid cells are crucial for lung defense against Pseudomonas (P.) aeruginosa infection. This study aimed to investigate the role of Dnmt3b in neutrophils and myeloid cells during acute pneumonia caused by P. aeruginosa. Neutrophil-specific (Dnmt3bfl/flMrp8Cre) or myeloid cell-specific (Dnmt3bfl/flLysMCre) Dnmt3b-deficient mice and littermate control mice were infected with P. aeruginosa PAK via the airways. Bacteria burdens, neutrophil recruitment, and activation (CD11b expression, myeloperoxidase, and elastase levels), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF) were measured in bronchoalveolar lavage fluid (BALF) at 6 and 24 h after infection. Our data showed that the bacterial loads and neutrophil recruitment and activation did not differ in BALF obtained from neutrophil-specific Dnmt3b-deficient and control mice, whilst BALF IL-6 and TNF levels were lower in the former group at 24 but not at 6 h after infection. None of the host response parameters measured differed between myeloid cell-specific Dnmt3b-deficient and control mice. In conclusion, dnmt3b deficiency in neutrophils or myeloid cells does not affect acute immune responses in the airways during Pseudomonas pneumonia.

Preconditioning the rat heart with 5-azacytidine attenuates myocardial ischemia/reperfusion injury via PI3K/GSK3β and mitochondrial KATP signaling axis

5-Azacytidine is well known for its clinical usage in cancer treatments. The present study investigates the role of 5-azacytidine as a cardioprotective agent to ameliorate ischemia/reperfusion (I/R) injury. The cardioprotective effect of 5-azacytidine was evaluated in three experimental models: in vitro, ex vivo, and in vivo. The cardioprotective effect was evaluated via cell viability, hemodynamic indices, infarct size measurement, and assessment of histopathology, oxidative stress, and mitochondrial function. The experiments were repeated in the presence of PI3K/GSK3β and mitochondrial K_ATP (mtK_ATP ) cardioprotective signaling pathway inhibitors to understand the underlying mechanism. 5-Azacytidine improved the cell viability by 29% in I/R-challenged H9C2 cells. Both isolated rat heart and LAD ligation model confirmed the infarct sparing effect of 5-azacytidine against I/R. It also provided a beneficial effect by normalizing the altered hemodynamics, reducing the infarct size and cardiac injury markers, reversing the perturbation of mitochondria, reduced oxidative stress, and improved the pPI3K and pAKT protein expression from I/R. In addition, it also augmented the activation of PI3K/AKT and mtK_ATP signaling pathway, confirmed by using wortmannin (PI3K inhibitor), SB216763 (GSK3β inhibitor), and glibenclamide (mtK_ATP channel closer). The effectiveness of 5-azacytidine as a cardioprotective agent is attributed to its activation of the PI3K/GSK3β and mtK_ATP channel signaling axis, thereby preserving mitochondrial function and reducing oxidative stress.

The Role of Host Cell DNA Methylation in the Immune Response to Bacterial Infection

Host cells undergo complex transcriptional reprogramming upon infection. Epigenetic changes play a key role in the immune response to bacteria, among which DNA modifications that include methylation have received much attention in recent years. The extent of DNA methylation is well known to regulate gene expression. Whilst historically DNA methylation was considered to be a stable epigenetic modification, accumulating evidence indicates that DNA methylation patterns can be altered rapidly upon exposure of cells to changing environments and pathogens. Furthermore, the action of proteins regulating DNA methylation, particularly DNA methyltransferases and ten-eleven translocation methylcytosine dioxygenases, may be modulated, at least in part, by bacteria. This review discusses the principles of DNA methylation, and recent insights about the regulation of host DNA methylation during bacterial infection.

Epigenetic Regulation in Sepsis, Role in Pathophysiology and Therapeutic Perspective

Sepsis is characterized by an initial hyperinflammatory response, with intense cell activation and cytokine storm. In parallel, a prolonged compensatory anti-inflammatory response, known as immunological tolerance, can lead to immunosuppression. Clinically, this condition is associated with multiple organ failure, resulting in the patient's death. The mechanisms underlying the pathophysiology of sepsis are not yet fully understood, but evidence is strong showing that epigenetic changes, including DNA methylation and post-translational modifications of histones, modulate the inflammatory response of sepsis. During the onset of infection, host cells undergo epigenetic changes that favor pathogen survival. Besides, epigenetic changes in essential genes also orchestrate the patient's inflammatory response. In this review, we gathered studies on sepsis and epigenetics to show the central role of epigenetic mechanisms in various aspects of the pathogenesis of sepsis and the potential of epigenetic interventions for its treatment.

Reversing Post-Infectious Epigenetic-Mediated Immune Suppression

The immune response must balance the pro-inflammatory, cell-mediated cytotoxicity with the anti-inflammatory and wound repair response. Epigenetic mechanisms mediate this balance and limit host immunity from inducing exuberant collateral damage to host tissue after severe and chronic infections. However, following treatment for these infections, including sepsis, pneumonia, hepatitis B, hepatitis C, HIV, tuberculosis (TB) or schistosomiasis, detrimental epigenetic scars persist, and result in long-lasting immune suppression. This is hypothesized to be one of the contributing mechanisms explaining why survivors of infection have increased all-cause mortality and increased rates of unrelated secondary infections. The mechanisms that induce epigenetic-mediated immune suppression have been demonstrated in-vitro and in animal models. Modulation of the AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR), nuclear factor of activated T cells (NFAT) or nuclear receptor (NR4A) pathways is able to block or reverse the development of detrimental epigenetic scars. Similarly, drugs that directly modify epigenetic enzymes, such as those that inhibit histone deacetylases (HDAC) inhibitors, DNA hypomethylating agents or modifiers of the Nucleosome Remodeling and DNA methylation (NuRD) complex or Polycomb Repressive Complex (PRC) have demonstrated capacity to restore host immunity in the setting of cancer-, LCMV- or murine sepsis-induced epigenetic-mediated immune suppression. A third clinically feasible strategy for reversing detrimental epigenetic scars includes bioengineering approaches to either directly reverse the detrimental epigenetic marks or to modify the epigenetic enzymes or transcription factors that induce detrimental epigenetic scars. Each of these approaches, alone or in combination, have ablated or reversed detrimental epigenetic marks in in-vitro or in animal models; translational studies are now required to evaluate clinical applicability.

Potential of Mesenchymal Stem Cells in the Rejuvenation of the Aging Immune System

Rapid growth of the geriatric population has been made possible with advancements in pharmaceutical and health sciences. Hence, age-associated diseases are becoming more common. Aging encompasses deterioration of the immune system, known as immunosenescence. Dysregulation of the immune cell production, differentiation, and functioning lead to a chronic subclinical inflammatory state termed inflammaging. The hallmarks of the aging immune system are decreased naïve cells, increased memory cells, and increased serum levels of pro-inflammatory cytokines. Mesenchymal stem cell (MSC) transplantation is a promising solution to halt immunosenescence as the cells have excellent immunomodulatory functions and low immunogenicity. This review compiles the present knowledge of the causes and changes of the aging immune system and the potential of MSC transplantation as a regenerative therapy for immunosenescence.

Screening of Key Genes of Sepsis and Septic Shock Using Bioinformatics Analysis

Objective

Sepsis is a disease associated with high mortality. We performed bioinformatic analysis to identify key biomarkers associated with sepsis and septic shock.

Methods

The top 20% of genes showing the greatest variance between sepsis and controls in the GSE13904 dataset (children) were screened by co-expression network analysis. The differentially expressed genes (DEGs) were identified through analyzing differential gene expression between sepsis patients and control in the GSE13904 (children) and GSE154918 (adult) data sets. Intersection analysis of module genes and DEGs was performed to identify common DEGs for enrichment analysis, protein-protein interaction network (PPI network) analysis, and Short Time-series Expression Miner (STEM) analysis. The PPI network genes were ranked by degree of connectivity, and the top 100 sepsis-associated genes were identified based on the area under the receiver operating characteristic curve (AUC). In addition, we evaluated differences in immune cell infiltration between sepsis patients and controls in children (GSE13904, GSE25504) and adults (GSE9960, GSE154918). Finally, we analyzed differences in DNA methylation levels between sepsis patients and controls in GSE138074 (adults).

Results

The common genes were associated mainly with up-regulated inflammatory and metabolic responses, as well as down-regulated immune responses. Sepsis patients showed lower infiltration by most types of immune cells. Genes in the PPI network with AUC values greater than 0.9 in both GSE13904 (children) and GSE154918 (adults) were screened as key genes for diagnosis. These key genes (MAPK14, FGR, RHOG, LAT, PRKACB, UBE2Q2, ITK, IL2RB, and CD247) were also identified in STEM analysis to be progressively dysregulated across controls, sepsis patients and patients with septic shock. In addition, the expression of MAPK14, FGR, and CD247 was modified by methylation.

Conclusion

This study identified several potential diagnostic genes and inflammatory and metabolic responses mechanisms associated with the development of sepsis.