MicroRNA and heme oxygenase-1 in allergic disease

Exosomal miR-205-5p contributes to the immune liver injury induced by trichloroethylene: Pivotal role of RORα mediating M1 Kupffer cell polarization

Trichloroethylene (TCE) is a common environmental contaminant that can induce occupational dermatitis medicamentosa-like TCE (ODMLT), where the liver damage is the most common complication. The study aims to uncover the underlying mechanism of TCE-sensitization-induced liver damage by targeting specific exosomal microRNAs (miRNAs). Among the enriched serum exosomal miRNAs of ODMLT patients, miR-205-5p had a significant correlation coefficient with the liver function damage indicators. Moreover, retinoic acid receptor-related orphan receptor α (RORα) was identified as a direct target of miR-205-5p via specific binding. Further experiments showed that kupffer cells (KCs) underwent M1 phenotypic and functional changes in liver injury induced by TCE which were alleviated by reducing the expression of miR-205-5p. However, this alleviation was reversed by the RORα antagonist SR1001. In vitro experiments showed that miR-205-5p promoted M1 polarization of macrophages and enhanced the secretion of inflammatory factors by regulating RORα. An increase in RORα reversed the polarization direction of M1-type macrophages and reduced the secretion of proinflammatory factors. In addition, pretreatment of mice with SR1078, a specific RORα agonist, effectively blocked M1 polarization of KCs and reduced the severity of TCE-induced liver injury. Our study uncovers that miR-205-5p regulates KC M1 polarization by targeting RORα in immune liver injury induced by TCE sensitization, providing new insight into the molecular mechanisms and new therapeutic targets for ODMLT.

Hyperforin Enhances Heme Oxygenase-1 Expression Triggering Lipid Peroxidation in BRAF-Mutated Melanoma Cells and Hampers the Expression of Pro-Metastatic Markers

Hyperforin (HPF) is an acylphloroglucinol compound found abundantly in Hypericum perforatum extract which exhibits antidepressant, anti-inflammatory, antimicrobial, and antitumor activities. Our recent study revealed a potent antimelanoma effect of HPF, which hinders melanoma cell proliferation, motility, colony formation, and induces apoptosis. Furthermore, we have identified glutathione peroxidase-4 (GPX-4), a key enzyme involved in cellular protection against iron-induced lipid peroxidation, as one of the molecular targets of HPF. Thus, in three BRAF-mutated melanoma cell lines, we investigated whether iron unbalance and lipid peroxidation may be a part of the molecular mechanisms underlying the antimelanoma activity of HPF. Initially, we focused on heme oxygenase-1 (HO-1), which catalyzes the heme group into CO, biliverdin, and free iron, and observed that HPF treatment triggered the expression of this inducible enzyme. In order to investigate the mechanism involved in HO-1 induction, we verified that HPF downregulates the BTB and CNC homology 1 (BACH-1) transcription factor, an inhibitor of the heme oxygenase 1 (HMOX-1) gene transcription. Remarkably, we observed a partial recovery of cell viability and an increase in the expression of the phosphorylated and active form of retinoblastoma protein when we suppressed the HMOX-1 gene using HMOX-1 siRNA while HPF was present. This suggests that the HO-1 pathway is involved in the cytostatic effect of HPF in melanoma cells. To explore whether lipid peroxidation is induced, we conducted cytofluorimetric analysis and observed a significant increase in the fluorescence of the BODIPY C-11 probe 48 h after HPF administration in all tested melanoma cell lines. To discover the mechanism by which HPF triggers lipid peroxidation, along with the induction of HO-1, we examined the expression of additional proteins associated with iron homeostasis and lipid peroxidation. After HPF administration, we confirmed the downregulation of GPX-4 and observed low expression levels of SLC7A11, a cystine transporter crucial for the glutathione production, and ferritin, able to sequester free iron. A decreased expression level of these proteins can sensitize cells to lipid peroxidation. On the other hand, HPF treatment resulted in increased expression levels of transferrin, which facilitates iron uptake, and LC3B proteins, a molecular marker of autophagy induction. Indeed, ferritin and GPX-4 have been reported to be digested during autophagy. Altogether, these findings suggest that HPF induced lipid peroxidation likely through iron overloading and decreasing the expression of proteins that protect cells from lipid peroxidation. Finally, we examined the expression levels of proteins associated with melanoma cell invasion and metastatic potential. We observed the decreased expression of CD133, octamer-4, tyrosine-kinase receptor AXL, urokinase plasminogen activator receptor, and metalloproteinase-2 following HPF treatment. These findings provide further support for our previous observations, demonstrating the inhibitory effects of HPF on cell motility and colony formation in soft agar, which are both metastasis-related processes in tumor cells.

d-Leucine protects oocytes from chronic psychological stress in mice

PURPOSE

Psychological stress could negatively influence female reproductive ability. d-Leucine (d-Leu) is a d-type amino acid found in foods and mammalian tissues. We have examined the protective effects of d-Leu on oocyte abnormality induced by psychological stress.

METHODS

Female mice (6-week-old) were divided into three groups: control, restraint stress (RS), and RS/d-Leu. The RS and RS/d-Leu mice were holed for 3 hours daily during 14 days. RS/d-Leu mice were fed 0.3% d-Leu diet. The oocyte maturation failure was analyzed by shapes of spindles and chromosomes. In addition, levels of heme-oxygenase-1 (HO-1) and superoxide dismutase (SOD) expression in the ovaries were also examined. Whether d-Leu reduces the generation of reactive oxygen species (ROS) in cultured cells, K562 cells were treated with d-Leu, and then ROS in K562 were analyzed.

RESULTS

Oocyte maturation failure was increased in RS mice. d-Leu reduced abnormal oocytes to control level. The expression levels of HO-1 and SOD2 increased in RS/d-Leu mice compared to those of RS mice. ROS levels were decreased in K562 cells with d-Leu in a dose-dependent manner.

CONCLUSIONS

We concluded that d-Leu protects oocytes from psychological stress through the induction of HO-1 and SOD2 expression then by reducing oxidative stress.

Cell-penetrating heme oxygenase-1 in the therapy of atopic dermatitis in mice

Atopic dermatitis (AD), also referred to as atopic eczema, is a long-term inflammatory condition that is characterized by itchy, red, swollen and cracked skin. Accumulating evidence suggests that AD is caused by genetic factors, environmental exposure and immune system dysfunction; however, its underlying molecular mechanism remains unclear. Current treatment strategies aim to decrease the severity and frequency of flares. Heme oxygenase-1 (HO-1) is a nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated gene that plays crucial roles against stress, inflammation and oxidation, and exerts cytoprotective effects. Previous studies have reported that treatment of AD induces high expression levels of HO-1 and Nrf2, indicating that HO-1 may play an important role in the treatment of AD. The present study constructed the recombinant protein, cell-penetrating peptide-HO-1 (CPP-HO-1), which was expressed in Escherichia coli and isolated with a 6xHis-tag using HiTrap His column (1 ml). AD was established using 4-dinitrochlorobenzene (DNCB) in mice. It was observed that the CPP-HO-1 fusion protein decreased the severity of AD, inhibited scratching in mice and decreased skin inflammation. Taken together, the results of the present study suggested that the CPP-HO-1 fusion protein may play a protective role against DNCB-induced AD in mice.

Catalpol exerts antiallergic effects in IgE/ovalbumin-activated mast cells and a murine model of ovalbumin-induced allergic asthma

Immunoglobulin E (IgE) and mast cells play important roles in the pathogenesis of allergic asthma. Catalpol, an iridoid glycoside, exerts many biological functions including anti-inflammatory activities. Herein, we investigated catalpol to determine both its antiallergic effects on IgE/ovalbumin (OVA)-stimulated mouse bone marrow-derived mast cells and its therapeutic actions in murine allergic asthma. We found that catalpol dramatically suppressed IgE/OVA-induced mast cell degranulation. Meanwhile, 5 ~ 100 μM of catalpol neither affected the expression level of the high-affinity receptor of IgE (FcεRI) by mast cells nor induced mast cell apoptosis. In addition, mRNA expression levels of inflammatory enzymes including cyclooxygenase (COX)-1, COX-2, and 5-lipoxygenase were downregulated. Administration of catalpol also suppressed production of prostaglandin D₂ (PGD₂), interleukin (IL)-6, and IL-13, while not affecting tumor necrosis factor (TNF)-α production. Further, catalpol pretreatment significantly attenuated the FcεRI-mediated Akt signaling pathway. In mice with IgE/OVA-induced asthma, oral administration of catalpol remarkably suppressed the production of OVA-specific IgE, the development of airway hyperresponsiveness (AHR), and the infiltration of eosinophils and neutrophils into the lungs. Histological studies demonstrated that catalpol substantially inhibited the recruitment of mast cells and increased mucus production in lung tissues. Catalpol-treated mice had significantly lower levels of helper T cell type 2 (Th2) cytokines (IL-4, IL-5, and IL-13), PGD₂, eotaxin-1, and C-X-C chemokine ligand-1 (CXCL1) in bronchoalveolar lavage fluid (BALF) than did the allergic group. Collectively, these results indicated that the suppressive effects of catalpol on degranulation and mediator generation by mast cells were beneficial in treating allergic asthma.

3,4,5‑Trihydroxycinnamic acid exerts anti‑inflammatory effects on TNF‑α/IFN‑γ‑stimulated HaCaT cells

3,4,5-Trihydroxycinnamic acid (THCA) exhibits anti-inflammatory activity in acute or chronic inflammatory disorders, such as acute lung injury and asthma. The present study investigated the anti-inflammatory activity of THCA in a tumor necrosis factor-α/interferon-γ (TI) mixture-stimulated human keratinocyte cell line. The results of ELISA and reverse transcription-quantitative PCR revealed that THCA reduced the secretion and mRNA expression levels of interleukin (IL)-6; IL-8; thymus and activation-regulated chemokine; macrophage-derived chemokine; regulated upon activation, normal T cell expressed and secreted; and monocyte chemoattractant protein-1 in TI mixture-stimulated HaCaT cells. In addition, the results of western blot analysis demonstrated that THCA exerted inhibitory activity on the activation of AKT, ERK and nuclear factor-κB in TI mixture-stimulated HaCaT cells. Furthermore, THCA upregulated the expression levels of heme oxygenase-1 and NAD(P)H:quinone oxidoreductase 1, and the activation of nuclear factor erythroid 2-related factor 2 in HaCaT cells. These results demonstrated that THCA may exhibit anti-inflammatory activity in activated HaCaT cells.

Heme Oxgenase-1, a Cardinal Modulator of Regulated Cell Death and Inflammation

Heme oxygenase catalyzes the rate-limiting step in heme degradation in order to generate biliverdin, carbon monoxide (CO), and iron. The inducible form of the enzyme, heme oxygenase-1 (HO-1), exerts a central role in cellular protection. The substrate, heme, is a potent pro-oxidant that can accelerate inflammatory injury and promote cell death. HO-1 has been implicated as a key mediator of inflammatory cell and tissue injury, as validated in preclinical models of acute lung injury and sepsis. A large body of work has also implicated HO-1 as a cytoprotective molecule against various forms of cell death, including necrosis, apoptosis and newly recognized regulated cell death (RCD) programs such as necroptosis, pyroptosis, and ferroptosis. While the antiapoptotic potential of HO-1 and its reaction product CO in apoptosis regulation has been extensively characterized, relatively fewer studies have explored the regulatory role of HO-1 in other forms of necrotic and inflammatory RCD (i.e., pyroptosis, necroptosis and ferroptosis). HO-1 may provide anti-inflammatory protection in necroptosis or pyroptosis. In contrast, in ferroptosis, HO-1 may play a pro-death role via enhancing iron release. HO-1 has also been implicated in co-regulation of autophagy, a cellular homeostatic program for catabolic recycling of proteins and organelles. While autophagy is primarily associated with cell survival, its occurrence can coincide with RCD programs. This review will summarize the roles of HO-1 and its reaction products in co-regulating RCD and autophagy programs, with its implication for both protective and detrimental tissue responses, with emphasis on how these impact HO-1 as a candidate therapeutic target in disease.

Peroxidan Plays a Tumor-Promoting Role in Oral Squamous Cell Carcinoma

Despite dramatic progress in cancer diagnosis and treatment, the five-year survival rate of oral squamous cell carcinoma (OSCC) is still only about 50%. Thus, the need for elucidating the molecular mechanisms underlying OSCC is urgent. We previously identified the peroxidasin gene (PXDN) as one of several novel genes associated with OSCC. Although the PXDN protein is known to act as a tumor-promoting factor associated with the Warburg effect, its function and role in OSCC are poorly understood. In this study, we investigated the expression, function, and relationship with the Warburg effect of PXDN in OSCC. In immunohistochemical analysis of OSCC specimens, we observed that elevated PXDN expression correlated with lymph node metastasis and a diffuse invasion pattern. High PXDN expression was confirmed as an independent predictor of poor prognosis by multivariate analysis. The PXDN expression level correlated positively with that of pyruvate kinase (PKM2) and heme oxygenase-1 (HMOX1) and with lactate and ATP production. No relationship between PXDN expression and mitochondrial activation was observed, and PXDN expression correlated inversely with reactive oxygen species (ROS) production. These results suggest that PXDN might be a tumor progression factor causing a Warburg-like effect in OSCC.

MiR-96-5p promotes breast cancer migration by activating MEK/ERK signaling

BACKGROUND

Breast cancer is the leading cause of cancer deaths in women worldwide. The purpose of the current study was to investigate the potential role of miR-96-5p in breast cancer.

METHODS

Breast cancer tissues and matched para-cancerous tissues were collected. The expression of microRNA-96-5p (miR-96-5p) and arginine kinase 3 (AK3) was detected by quantitative real-time PCR (qRT-PCR). The correlation between miR-96-5p and AK3 was calculated by Pearson's Chi-square test. Moreover, mimics or inhibitors of miR-96-5p were applied to explore whether miR-96-5p influences the migration capacity in Transwell and wound healing assays. Bioinformatics analysis was performed to identify the target genes of miR-96-5p through the TargetScan, miRDB and miRanda databases. A luciferase reporter assay was performed to verify AK3 as a downstream target gene of miR-96-5p.

RESULTS

The expression of miR-96-5p was significantly increased in breast cancer tissue and breast cancer cell lines compared with para-cancerous tissue and a breast cell line, respectively. The expression of miR-96-5p negatively correlated with AK3 gene expression. AK3 was demonstrated to be a direct mRNA target of miR-96-5p. AK3 was positively associated with the overall survival of breast cancer patients. Kaplan-Meier curve and log rank test analyses revealed that decreased AK3 levels were significantly associated with reduced overall survival. miR-96-5p was shown to promote the migration of breast cancer cells through the MEK/ERK signaling pathway.

CONCLUSION

Our results identify a role for miR-96-5p in promoting breast cancer cell migration through activation of MEK/ERK signaling by targeting AK3.