Apoptosis signal-regulating kinase 1 (ASK1) inhibition reduces endothelial cytokine production without improving permeability after toll-like receptor 4 (TLR4) challenge

The Function of ASK1 in Sepsis and Stress-Induced Disorders

Apoptosis signal-regulating kinase 1 (ASK1) is a serine-threonine kinase that is ubiquitously expressed in nucleated cells and is responsible for the activation of multiple mitogen-activated protein kinases (MAPK) to regulate cell stress. Activation of ASK1 via cellular stress leads to activation of downstream signaling components, activation of transcription factors, and proinflammatory cytokine production. ASK1 is also expressed in anucleate platelets and is a key player in platelet activation as it is important for signaling. Interestingly, the mechanism of ASK1 activation is cell type-dependent. In this review we will explore how ASK1 regulates a variety of cellular processes from innate immune function to thrombosis and hemostasis. We will discuss how ASK1 influences FcγRIIA-mediated platelet reactivity and how that reactivity drives platelet clearance. Furthermore, we will explore the role of ASK1 in thromboxane (TxA2) generation, which highlights differences in the way ASK1 functions in mouse and human platelets.

Synergistic effects of ozone with doxorubicin on the proliferation, apoptosis and metastatic profile of luminal-B type human breast cancer cell line

OBJECTIVE

Luminal-B type human breast cancer cell line (BT-474) to assess the synergistic effects of ozone applied after chemotherapeutic treatment with various dosages of doxorubicin, and compare the results with the effects on L929 fibroblast cell line.

METHODS

Doxorubicin (1-50 M) was added to each cell lines and left to sit for 24 h at 37 °C. Then, as combination groups, half of the groups were incubated with 30 g/mL ozone for 25 min. Tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), and matrix metalloproteinase-2 and - 9 (MMP-2 and MMP-9) levels were measured using the MTT test, flow cytometry, and immunocytochemistry, respectively.

RESULTS

When compared to simply doxorubicin-applied cells without ozone treatment, each dose of doxorubicin + ozone treatment considerably boosted L929 viability but significantly decreased BT-474 viability. Additionally, the combination increased the apoptotic impact of doxorubicin on BT-474 but not L929 (P < 0.001). TGF-, MMP-2, and MMP-9 levels of L929 after combination were substantially higher than those of the other groups (P < 0.01). Doxorubicin's effect on BT-474's protein levels, which had significantly decreased in comparison to those of the other groups, was reversed by the combination treatment (P < 0.05).

CONCLUSION

Doxorubicin's anti-proliferative and apoptotic effects were enhanced by ozone treatment in BT-474 cells, but it also repaired and healed healthy fibroblast cells that had been harmed by the cytotoxicity of the chemotherapy drug. If doxorubicin and ozone treatment are coupled, BT-474 cells may develop resistance to it through expressions of TNF-α, TGF-β, MMP-2, and MMP-9.

ASK1-K716R reduces neuroinflammation and white matter injury via preserving blood-brain barrier integrity after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a significant worldwide public health concern that necessitates attention. Apoptosis signal-regulating kinase 1 (ASK1), a key player in various central nervous system (CNS) diseases, has garnered interest for its potential neuroprotective effects against ischemic stroke and epilepsy when deleted. Nonetheless, the specific impact of ASK1 on TBI and its underlying mechanisms remain elusive. Notably, mutation of ATP-binding sites, such as lysine residues, can lead to catalytic inactivation of ASK1. To address these knowledge gaps, we generated transgenic mice harboring a site-specific mutant ASK1 Map3k5-e (K716R), enabling us to assess its effects and elucidate potential underlying mechanisms following TBI.

METHODS

We employed the CRIPR/Cas9 system to generate a transgenic mouse model carrying the ASK1-K716R mutation, aming to investigate the functional implications of this specific mutant. The controlled cortical impact method was utilized to induce TBI. Expression and distribution of ASK1 were detected through Western blotting and immunofluorescence staining, respectively. The ASK1 kinase activity after TBI was detected by a specific ASK1 kinase activity kit. Cerebral microvessels were isolated by gradient centrifugation using dextran. Immunofluorescence staining was performed to evaluate blood-brain barrier (BBB) damage. BBB ultrastructure was visualized using transmission electron microscopy, while the expression levels of endothelial tight junction proteins and ASK1 signaling pathway proteins was detected by Western blotting. To investigate TBI-induced neuroinflammation, we conducted immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR) and flow cytometry analyses. Additionally, immunofluorescence staining and electrophysiological compound action potentials were conducted to evaluate gray and white matter injury. Finally, sensorimotor function and cognitive function were assessed by a battery of behavioral tests.

RESULTS

The activity of ASK1-K716R was significantly decreased following TBI. Western blotting confirmed that ASK1-K716R effectively inhibited the phosphorylation of ASK1, JNKs, and p38 in response to TBI. Additionally, ASK1-K716R demonstrated a protective function in maintaining BBB integrity by suppressing ASK1/JNKs activity in endothelial cells, thereby reducing the degradation of tight junction proteins following TBI. Besides, ASK1-K716R effectively suppressed the infiltration of peripheral immune cells into the brain parenchyma, decreased the number of proinflammatory-like microglia/macrophages, increased the number of anti-inflammatory-like microglia/macrophages, and downregulated expression of several proinflammatory factors. Furthermore, ASK1-K716R attenuated white matter injury and improved the nerve conduction function of both myelinated and unmyelinated fibers after TBI. Finally, our findings demonstrated that ASK1-K716R exhibited favorable long-term functional and histological outcomes in the aftermath of TBI.

CONCLUSION

ASK1-K716R preserves BBB integrity by inhibiting ASK1/JNKs pathway in endothelial cells, consequently reducing the degradation of tight junction proteins. Additionally, it alleviates early neuroinflammation by inhibiting the infiltration of peripheral immune cells into the brain parenchyma and modulating the polarization of microglia/macrophages. These beneficial effects of ASK1-K716R subsequently result in a reduction in white matter injury and promote the long-term recovery of neurological function following TBI.

The role of TLR4-mediated MyD88/TRAF6/NF-κB signaling and pIgR intestinal expression in chicks during Salmonella enteritidis infection

To observe the effect of Salmonella enteritidis (SE)-induced inflammation on pIgR expression in jejunum and ileum. Salmonella enteritidis was orally administered to 7-day old Hyline chicks, which were killed after 1d,3d,7d and 14d. The mRNA expression of TLR4,MyD88,TRAF6,NF-κB, and pIgR was detected by real-time RT-PCR, and pIgR protein was detected by Western blotting. The TLR4 signaling pathway was activated, the mRNA expression of the pIgR in jejunum and ileum was increased, and pIgR protein in jejunum and ileum was up-regulated by SE. In SE-treated chicks,the pIgR in jejunum and ileum was up-regulated on mRNA,and protein level,associated with activation of the TRL4-mediated MyD88/TRAF6/NF-κB signaling pathway, which identifies this as a novel pIgR-related pathway to TLR4 activation.

Tumor Vasculature as an Emerging Pharmacological Target to Promote Anti-Tumor Immunity

Tumor vasculature abnormality creates a microenvironment that is not suitable for anti-tumor immune response and thereby induces resistance to immunotherapy. Remodeling of dysfunctional tumor blood vessels by anti-angiogenic approaches, known as vascular normalization, reshapes the tumor microenvironment toward an immune-favorable one and improves the effectiveness of immunotherapy. The tumor vasculature serves as a potential pharmacological target with the capacity of promoting an anti-tumor immune response. In this review, the molecular mechanisms involved in tumor vascular microenvironment-modulated immune reactions are summarized. In addition, the evidence of pre-clinical and clinical studies for the combined targeting of pro-angiogenic signaling and immune checkpoint molecules with therapeutic potential are highlighted. The heterogeneity of endothelial cells in tumors that regulate tissue-specific immune responses is also discussed. The crosstalk between tumor endothelial cells and immune cells in individual tissues is postulated to have a unique molecular signature and may be considered as a potential target for the development of new immunotherapeutic approaches.

Noncoding RNA-mediated regulation of pyroptotic cell death in cancer

Pyroptosis is a newly discovered form of programmed cell death, which is manifested by DNA fragmentation, cell swelling, cell membrane rupture and leakage of cell contents. Previous studies have demonstrated that pyroptosis is tightly associated with the initiation and development of various cancers, whereas the molecular mechanisms underlying pyroptosis remain obscure. Noncoding RNAs (ncRNAs) are a type of heterogeneous transcripts that are broadly expressed in mammalian cells. Owing to their potency of regulating gene expression, ncRNAs play essential roles in physiological and pathological processes. NcRNAs are increasingly acknowledged as important regulators of the pyroptosis process. Importantly, the crosstalk between ncRNAs and pyroptosis affects various hallmarks of cancer, including cell growth, survival, metastasis and therapeutic resistance. The study of the involvement of pyroptosis-associated ncRNAs in cancer pathobiology has become a hot area in recent years, while there are limited reviews on this topic. Herein, we provide an overview of the complicated roles of ncRNAs, mainly including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), in modulating pyroptosis, with a focus on the underlying mechanisms of the ncRNA-pyroptosis axis in cancer pathogenesis. Finally, we discuss the potential applications and challenges of exploiting pyroptosis-regulating ncRNAs as molecular biomarkers and therapeutic targets in cancer.

Screening of potential key ferroptosis-related genes in sepsis

Background

Sepsis leads to multiple organ dysfunction caused by a dysregulated host response to infection with a high incidence and mortality. The effect of ferroptosis on the development of sepsis remains unclear. In this study, we aimed to identify the key ferroptosis-related genes involved in sepsis and further explore the potential biological functions of these ferroptosis-related genes in sepsis using bioinformatics analysis.

Methods

The GSE13904 (from children) and GSE28750 (from adults) datasets were downloaded from the Gene Expression Omnibus (GEO). The ferroptosis-related genes were obtained from the FerrDb database. The ferroptosis-related differentially expressed genes (DEGs) were screened by the limma R package. The DAVID online database or clusterProfiler R package was used for the functional enrichment analysis. Then, the STRING database was used to predict the interactions of proteins, and the CytoHubba plugin of Cytoscape was used to confirm key clustering modules. Then, the miRNAs and lncRNAs associated with the key clustering modules were predicted by miRWalk 2.0 and LncBase v.2 respectively. Finally, we generated a cecal ligation and puncture (CLP) polymicrobial sepsis model in C57 male mice and examined the expression of the mRNAs and noncoding RNAs of interest in peripheral blood leukocytes by PCR during the acute inflammation phase.

Results

In total, 34 ferroptosis-related DEGs were identified in both adult and pediatric septic patients. These ferroptosis-related DEGs were mainly enriched in inflammatory pathways. Then, a significant clustering module containing eight genes was identified. Among them, the following five genes were closely associated with the MAPK signaling pathway: MAPK14, MAPK8, DUSP1, MAP3K5 and MAPK1. Then, crucial miRNAs and lncRNAs associated with biomarker MAPK-related genes were also identified. In particular, let-7b-5p and NEAT1 were selected as noncoding RNAs of interest because of their correlation with ferroptosis in previous studies. Finally, we examined the mRNAs, miRNAs and lncRNAs of interest using CLP-induced sepsis in peripheral blood leukocytes of mice. The results showed that MAPK14, MAPK8, MAP3K5, MAPK1 and NEAT1 were upregulated, while DUSP1 and let-7b-5p were downregulated in the CLP group compared with the sham group.

Conclusions

The MAPK signaling pathway may play a key role in regulating ferroptosis during sepsis. This study provides a valuable resource for future studies investigating the mechanism of MAPK-related ferroptosis in sepsis.

Histone deacetylase inhibitor attenuates intestinal mucosal injury in fatally scalded rats

Background

Severe burns, trauma and shock can cause intestinal epithelial barrier dysfunction, which can lead to intestinal endotoxemia and even sepsis and multi-organ dysfunction. Many studies have shown that histone deacetylase inhibitors (HDACIs) can improve cell tolerance to hypoxia and inflammation, thus protecting the functions of important organs in the body, and at the same time, inhibiting the degradation of tight junction (TJ) proteins, protecting the intercellular barrier, and reducing tissue edema and organ damage. However, the mechanism is unclear.

Methods

Eighty male Sprague-Dawley rats (weighing 280-300 g) with a 50% total body surface area full-thickness dermal burn were randomly assigned to 4 groups (20 rats/group): sham control (SC group), scald + normal saline (SN group), scald + 2-methyl-2pentenoic acid (2M2P group), and scald + valproic acid (VPA group). After scalding, we measured the following parameters at various time intervals postburn injury: intestinal mucosal injury score, diamine oxidase (DAO) activity, intestinal protein expression of acetyl histone H3 at K9 (Ac-H3K9), hypoxia inducible factor 1α (HIF-1α), erythropoietin (EPO), zonula occludens-1 (ZO-1), endothelial nitric oxide synthase (eNOS) content, nitric oxide (NO) content, and intestinal mucosal blood flow (IMBF).

Results

Intestinal mucosa showed significant morphologic injury at 4 and 8 hours after scalding that was attenuated by VPA. DAO activity in the VPA group was significantly decreased compared with the other scald groups. At 4 and 8 hours after scalding, VPA enhanced Ac-H3K9 and ZO-1 expression and decreased HIF-1α and EPO expression in the intestine compared with the other scald groups. At 4 and 8 hours after scalding, eNOS and NO protein content and IMBF in the VPA group were markedly increased compared with the other scald groups.

Conclusions

HDACIs attenuated intestinal mucosal injury in fatally scalded rats. This may have involved VPA enhancing Ac-H3K9 and ZO-1 expression, inhibiting HIF-1α and EPO expression and inducing eNOS and NO increments.

Cell penetrating peptides coupled to an endothelial nitric oxide synthase sequence alter endothelial permeability

Delivery of cargo to cells through the use of cell-penetrating peptide (CPP) sequences is an area of rich investigation for targeted therapeutics. Specific to the endothelium, the layer of cells that cover every blood vessel in the body, the loss or alteration of a key enzyme, endothelial nitric oxide synthase (eNOS), is known to contribute to endothelial health during severe, infectious challenge. While the beneficial effects of eNOS are often thought to be mediated through the generation of nitric oxide, some protection is theorized to be through eNOS binding to regulatory pathways via a pentabasic RRKRK motif. We hypothesized that delivery of the eNOS-RRKRK peptide sequence using common CPPs would allow protection against gram-negative lipopolysaccharide (LPS). Combination of the eNOS-RRKRK sequence to the CPP antennapedia (AP) reduced the impact of LPS-induced permeability in cultured human microvascular endothelial cells (HMVECs) as measured by transendothelial electrical resistance (TEER). There was also a modest reduction in cytokine production, however it was observed that AP alone significantly impaired LPS-induced endothelial permeability and cytokine production. In comparison, the CPP trans-activator of transcription (TAT) did not significantly alter endothelial inflammation by itself. When TAT was coupled to the eNOS-RRKRK sequence, protection against LPS-induced permeability was still demonstrated, however cytokine production was not reduced. These data demonstrate that the RRKRK sequence of eNOS can offer some NO-independent protection against LPS-mediated endothelial inflammation, however the degree of protection is highly dependent on the type of CPP utilized for cargo delivery.