JNK Signaling Research Articles

Cornuside improves murine autoimmune hepatitis through inhibition of inflammatory responses.

Autoimmune hepatitis (AIH) poses an important public health concern worldwide, with few therapeutic options available. Cornuside, a primary cornel iridoid glycoside present in Cornus officinalis Sieb. et Zucc., is a well-known traditional Chinese medicine that possesses anti-inflammatory, antioxidant and anti-apoptotic properties. However, the effects of cornuside on autoimmune diseases including AIH is still not defined, neither is clear on the mechanisms of cornuside in the suppression of inflammatory responses. The study was aimed to investigate the therapeutic effects of cornuside on AIH using murine models. A murine model of AIH induced by concanavalin A (Con A) was used to examine the pharmacological activity of cornuside in suppressing the inflammatory responses in vivo. C57BL/6J mice were intravenously with different doses of cornuside and challenged with 18mg/kg Con A 3h later. Network pharmacological analysis was performed to identify the potential target genes and signaling pathways by cornuside in AIH. Next serum and liver tissues were collected 12h after Con A injection to analyze the levels of markers for hepatic injury, apoptosis, oxidative stress, immune responses, and inflammation. Network pharmacological analysis revealed that cornuside may modulate oxidative stress and apoptosis in AIH. Compared with the Con A group, cornuside pretreatment significantly reduced the serum levels of alanine aminotransferase and aspartate aminotransferase, improving histopathological damage and apoptosis in the livers. In addition, cornuside decreased the levels of malondialdehyde, myeloperoxidase, but increased superoxide dismutase levels, suggesting the relieving of oxidative stress. Furthermore, cornuside suppressed the activation of T and natural killer T cells, whereas the proportion of myeloid-derived suppressor cells was significantly increased. The production of proinflammatory cytokines, including interleukin (IL)-6, IL-12, IL-1β, and tumor necrosis factor-alpha (TNF-α), was also clearly decreased. Finally, western blot analysis displayed that cornuside inhibited the phosphorylation of extracellular receptor kinase (ERK) and c-Jun N-terminal kinase (JNK). We demonstrated that cornuside has protective effects for Con A-induced immune-mediated hepatitis by suppressing the oxidative stress, apoptosis, and the inflammatory responses through the ERK and JNK signaling pathways, as well as by modulating the activation and recruitment of immune cells.

Broad spectrum post-entry inhibitors of coronavirus replication: Cardiotonic steroids and monensin

A small molecule screen identified several cardiotonic steroids (digitoxin and ouabain) and the ionophore monensin as potent inhibitors of HCoV-229E, HCoV-OC43, and SARS-CoV-2 replication with EC50s in the low nM range. Subsequent tests confirmed antiviral activity in primary cell models including human nasal epithelial cells and lung organoids. Addition of digitoxin, ouabain, or monensin strongly reduced viral gene expression as measured by both viral protein and RNA accumulation. Furthermore, the compounds acted post virus entry. While the antiviral activity of digitoxin was dependent upon activation of the MEK and JNK signaling pathways but not signaling through GPCRs, the antiviral effect of monensin was reversed upon inhibition of several signaling pathways. Together, the data demonstrates the potent anti-coronavirus properties of two classes of FDA approved drugs that function by altering the properties of the infected cell, rendering it unable to support virus replication.

Berberine derivative DCZ0358 induce oxidative damage by ROS-mediated JNK signaling in DLBCL cells

The most common neoplasm among adult lymphomas is diffuse large B-cell lymphoma (DLBCL), typically characterized by pain-free and progressive lymph node enlargement. Due to high heterogeneity of DLBCL, 30–40 % of patients are resistant to R-CHOP standard chemoimmunotherapy. DCZ0358 is a new compound designed and synthesized from berberine by our group and the molecular mechanism by which it inhibited DLBCL growth has attracted our widespread attention. In this study, we employed the CCK8 assay to reveal that DCZ0358 inhibited proliferation in a dependent manner of time and dosage of DLBCL cells. Moreover, flowcytometry and western blot results showed that DCZ0358 downregulated the expression of CDK4, CDK6 and CyclinD1 to block cell cycle progression in G0/G1 phase. Furthermore, DCZ0358 enhanced mitochondrial membrane potential depolarization, promoted mitochondrial permeability transport pore openness, increased cytoplastic Ca2+ levels and decreased intracellular adenosine triphosphate production, which led to mitochondrial dysfunction. In particular, DCZ0358 treatment triggered cell apoptosis and elevated intracellular reactive oxygen species (ROS) levels, which subsequently mediated JNK pathway activation. Further research indicated the pre-treatment with ROS scavenger N-acetylcysteine (NAC) and JNK inhibitor SP600125 could partially attenuate apoptosis and DNA damage triggered by DCZ0358. Most importantly, DCZ0358 exhibited synergistic anti-tumor effects when combined with etoposide, a common clinical anti-DLBCL drug, both in vitro and certainly in vivo. Above results demonstrated anti-tumor molecular mechanism of DCZ0358 in DLBCL cells and highlighted the ROS/JNK/DNA damage pathway as a potential target in therapies, which have implications for the development of more effective clinical treatments for DLBCL.

E2F1, DIAP1, and the presence of a homologous chromosome promote while JNK inhibits radiation-induced loss of heterozygosity in Drosophila melanogaster.

Loss of heterozygosity (LOH) can occur when a heterozygous mutant cell loses the remaining wild-type allele to become a homozygous mutant. LOH can have physiological consequences if, for example, the affected gene encodes a tumor suppressor. We used fluorescent reporters to study the mechanisms of LOH induction by X-rays, a type of ionizing radiation (IR), in Drosophila melanogaster larval wing discs. IR is used to treat more than half of patients with cancer, so understanding its effects is of biomedical relevance. Quantitative analysis of IR-induced LOH at different positions between the telomere and the centromere on the X chromosome showed a strong sex dependence and the need for a recombination-proficient homologous chromosome, whereas, paradoxically, position along the chromosome made little difference in LOH incidence. We propose that published data documenting high recombination frequency within centromeric heterochromatin on the X chromosome can explain these data. Using a focused screen, we identified E2F1 as a key promotor of LOH and further testing suggests a mechanism involving its role in cell-cycle regulation. We leveraged the loss of a transcriptional repressor through LOH to express transgenes specifically in cells that have already acquired LOH. This approach identified JNK signaling and apoptosis as key determinants of LOH maintenance. These studies reveal previously unknown mechanisms for the generation and elimination of cells with chromosome aberrations after exposure to IR.

Zearalenone promotes porcine ESCs apoptosis by enhancing Drp1-mediated mitochondrial fragmentation and activating the JNK pathway

Zearalenone (ZEA) is widely present in food and feed, and pigs are susceptible to its effects. This study explored the underlying function of ZEA-induced apoptosis in porcine endometrial stromal cells (ESCs) through activation of the JNK signaling pathway and mitochondrial division. This study utilized ESCs to explore the impact of exposure to ZEA. A mitochondrial division inhibitor (Mdivi) was also included as a reference. The results indicated a gradual decrease in cell viability with increasing ZEA concentration. In addition, ZEA can modify the growth status of porcine ESCs, disrupt their ultrastructure, and lead to apoptosis of porcine ESCs via the mitochondrial division pathway and JNK signaling pathway. In summary, our study found the critical targets of ZEA infected with pig ESCs, which provided a conceptual foundation to prevent and control ZEA.

JNK regulates ciliogenesis through the interflagellar transport complex and actin networks.

The c-Jun N-terminal kinase (JNK) regulates various important physiological processes. Although the JNK pathway has been under intense investigation for over 20 yr, its complexity is still perplexing, with multiple protein partners underlying the diversity of its activity. We show that JNK is associated with the basal bodies in both primary and motile cilia. Loss of JNK disrupts basal body migration and docking and leads to severe ciliogenesis defects. JNK's involvement in ciliogenesis stems from a dual role in the regulation of the actin networks of multiciliated cells (MCCs) and the establishment of the intraflagellar transport-B core complex. JNK signaling is also critical for the maintenance of the actin networks and ciliary function in mature MCCs. JNK is implicated in the development of diabetes, neurodegeneration, and liver disease, all of which have been linked to ciliary dysfunction. Our work uncovers a novel role of JNK in ciliogenesis and ciliary function that could have important implications for JNK's role in the disease.

Exosomes derived from platelet-rich plasma promote diabetic wound healing via the JAK2/STAT3 pathway

Diabetic non-healing wounds are bringing a heavy burden on patients and society. Platelet-rich plasma (PRP) has been widely applied in tissue regenerating for containing various growth factors. Recently, PRP-derived exosomes (PRP-Exos) have been proved to be more effective than PRP in tissue regeneration. However, few studies have investigated the therapeutic potential of PRP-Exos in diabetic wound healing to date. Therefore, we extracted and identified exosomes derived from PRP and tested its promoting effect on diabetic wound healing invivo and invitro. We found that high glucose (HG) inhibited cell proliferation and migration and induced apoptosis through ROS-dependent activation of the JNK and p38 MAPK signaling pathways. PRP-Exos can stimulate fibroblast functions and accelerate diabetic wound healing. The benefits of PRP-Exos may be attributed to its capability to prevent HG-induced ROS-dependent apoptosis via the PDGF-BB/JAK2/STAT3/Bcl-2 signaling pathway. This illustrates the therapeutic potential of PRP-Exos in diabetic wounds.

CCK-8 enhances acid-sensing ion channel currents in rat primary sensory neurons

Cholecystokinin (CCK) is a peptide that has been implicated in pain modulation. Acid sensitive ion channels (ASICs) also play an important role in pain associated with tissue acidification. However, it is still unclear whether there is an interaction between CCK signaling and ASICs during pain process. Herein, we report that a functional link between them in rat dorsal root ganglion (DRG) neurons. Pretreatment with CCK-8 concentration-dependently increased acid-evoked ASIC currents. CCK-8 increased the maximum response of ASICs to acid, but did not changed their acid sensitivity. Enhancement of ASIC currents by CCK-8 was mediated by the stimulation of CCK2 receptor (CCK2R), rather than CCK1R. The enhancement of ASIC currents by CCK-8 was prevented by application of either G-protein inhibitor GDP-β-S or protein kinase C (PKC) inhibitor GF109203×, but not by protein kinase A (PKA) inhibitor H-89 or JNK inhibitor SP600125. Moreover, CCK-8 increased the number of action potentials triggered by acid stimuli by activating CCK2R. Finally, CCK-8 dose-dependently exacerbated acid-induced nociceptive behavior in rats through local CCK2R. Together, these results indicated that CCK-8/CCK2R activation enhanced ASIC-mediated electrophysiological activity in DRG neurons and nociception in rats. The enhancement effect depended on G-proteins and intracellular PKC signaling rather than PKA and JNK signaling pathway. These findings provided that CCK-8/CCK2R is an important therapeutic target for ASIC-mediated pain.

Dietary supplementation with American ginseng dietary fiber ameliorates intestinal mucosal barrier injury in immunosuppressed mice

Dietary fiber is an important component of healthy eating patterns. Although American ginseng (Panax quiquefolium L.) is often used to improve body immunity, less attention has been paid to American ginseng dietary fiber (AGDF) in this regard. The aim of this study was to investigate the protective effect of AGDF on intestinal mucosal barrier injury induced by cyclophosphamide (CTX) in immunosuppressed mice and the underlying mechanism. The results showed that AGDF could increase immune organ index and enhance immunity of immunosuppressed mice, such as DTH response, lymphocyte transformation and proliferation and NK effector cell activity. At the same time, AGDF could restore the proportion of CD4+/CD8+ T lymphocytes induced by CTX to different extents, and promote the secretion of immunoglobulin IgG. More importantly, AGDF could up-regulate the contents of TNF-α, IFN-γ, IL-6 and IL-1β in serum and intestine of immunosuppressed mice, promote the secretion of cytokines and regulate the homeostasis balance between Th1/Th2 cytokines. It also upregulated the expression of tight junction proteins occludin, claudin-1 and ZO-1, and alleviated the degree of CTX-induced damage to the intestinal mucosal barrier. Meanwhile, AGDF could reduce intestinal epithelial cell apoptosis by activating TLR4/NF-κB signaling pathway, improving the phosphorylation of JNK and p38 signaling molecules, which may be the potential mechanism by which AGDF ameliorates intestinal mucosal injury in immunosuppressed mice. Therefore, AGDF may be used as a dietary supplement to prevent and treat intestinal mucosal barrier injury caused by CTX.

MEHP activates JNK to inhibit the migration of human foreskin fibroblasts

This study aimed to investigate the impact of mono(2-ethylhexyl) phthalate (MEHP) on the proliferation, apoptosis, and migration of human foreskin fibroblast cells (HFF-1) and the role of the JNK signaling pathway in cell migration. HFF-1 cells were randomly assigned to the control group with 0 MEHP exposure (M0) or the experimental groups with 25, 50, 100, 200, and 400 μmol/L MEHP exposure (M25, M50, M100, M200, and M400, respectively). After 24 and 48 h of MEHP exposure, the proliferation of HFF-1 cells in any group had no significant change. However, compared with the M0 group, the M200 and M400 groups presented substantially increased apoptosis of HFF-1 cells. Moreover, cell migration ability significantly decreased in all groups (p < 0.05). Additionally, the transcription and phosphorylated protein activation of JNK kinase in HFF-1 cells were substantially upregulated with the increase in MEHP exposure. Subsequently, HFF-1 cells were randomly divided into three groups: the DMSO blank control group, the 100 μM MEHP experimental group (M100), and the 100 μM MEHP plus 10 μM SP600125 (specific JNK inhibitor) experimental group (S10). The activation of JNK protein in HFF-1 cells was substantially downregulated in the S10 group. HFF-1 cells were also divided into the blank control group (M0). They were treated with 100 μM MEHP and varying concentrations of SP600125 (5, 10, and 15 μM for S5, S10, and S15, respectively). As the concentration of the antagonist increased, the migration ability of HFF-1 cells was returned to normal. Finally, the ROS in HFF-1 cells increased under MEHP exposure. This finding indicates that the regulation of cell migration by the JNK signaling pathway may be important in the occurrence of hypospadias.

Exploring dual effects of dinutuximab beta on cell death and proliferation of insulinoma.

Insulinoma INS-1 cells are pancreatic beta cell tumors. Dinutuximab beta (DB) is a monoclonal antibody used in the treatment of neuroblastoma. The aim of this study is to investigate the effects of DB on pancreatic beta cell tumors at the molecular level. DB (Qarziba®) was available from EUSA Pharma. Streptozotocin (STZ) was used induce to cell cytotoxicity. DB was applied to the cells before or after the STZ application. KCND3, KCNN4, KCNK1, and PTHrP gene expression levels were analyzed by q-RT-PCR, and protein levels were analyzed by Western blotting. Analysis of glucose-stimulated insulin secretion was performed. Ca+2 and CA19-9 levels were determined by the ELISA kit. PERK, CHOP, HSP90, p-c-Jun, p-Atf2, and p-Elk1 protein levels were analyzed by simple WES. Decreased KCND3, KCNK1, and PTHrP protein levels and increased KCND3, KCNN4, KCNK1, and PTHrP gene expression levels were observed with DB applied after STZ application. Cell dysfunction was detected with DB applied before and after STZ application. Ca19-9 and Ca+2 levels were increased with DB applied after STZ application. PERK, CHOP, and p-Elk1 levels decreased, while HSP90 levels increased with DB applied after STZ application. CHOP, p-Akt-2, and p-c-Jun levels increased in the DB group. As a result, INS-1 cells go to cell death via the ERK signaling pathway without ER stress and release insulin with the decrease of K+ channels and an increase in Ca+2 levels with DB applied after STZ application. Moreover, the cells proliferate via JNK signaling with DB application. DB holds promise for the treatment of insulinoma. The study should be supported by in vivo studies.

Modified 5-aminolevulinic acid photodynamic therapy induces cutaneous squamous cell carcinoma cell pyroptosis via the JNK signaling pathway

Modified 5-aminolevulinic acid photodynamic therapy (M-PDT) is a novel therapeutic modality for cutaneous squamous cell carcinoma (cSCC) that is reported to be effective and well tolerated. However, the mechanisms underlying its antitumor effects are not fully understood. In this research, we investigated the effects of M-PDT on pyroptosis, a form of programmed cell death characterized by cell swelling, ruptures of cell membrane, and inflammatory cytokine release, in two human cSCC cell lines, SCL-1 and HSC-5. We found that M-PDT triggered pyroptosis in a dose-dependent manner, as evidenced by increased lactate dehydrogenase release, propidium iodide staining, and expression of pyroptosis-related proteins, such as NLR family pyrin domain containing 3 (NLRP3), N-terminal of gasdermin D (N-GSDMD), cleaved caspase-1, and mature interleukin 1 beta (IL-1B) in both cell lines. This process was inhibited by treatment with MCC950, an NLRP3-specific inhibitor, suggesting the involvement of the NLRP3 inflammasome in M-PDT-induced pyroptosis. We also demonstrated that M-PDT activated c-Jun N-terminal kinase (JNK) signaling, which is required for pyroptosis induction, as treatment with SP600125, a JNK inhibitor, suppressed the expression of pyroptosis-related proteins after M-PDT. JNK activation enhanced M-PDT-induced pyroptosis, highlighting the significance of the JNK pathway in M-PDT. Moreover, M-PDT increased intracellular reactive oxygen species (ROS) levels, which are responsible for JNK activation and pyroptosis induction. In summary, our results revealed that M-PDT triggers pyroptosis through ROS-mediated JNK activation and subsequent NLRP3 inflammasome activation in cSCC cells, providing a better understanding of the molecular mechanism of M-PDT and promoting its clinical application.

Slik maintains tissue homeostasis by preventing JNK-mediated apoptosis

BackgroundThe c-Jun N-terminal kinase (JNK) pathway is an evolutionarily conserved regulator of cell death, which is essential for coordinating tissue homeostasis. In this study, we have characterized the Drosophila Ste20-like kinase Slik as a novel modulator of JNK pathway-mediated apoptotic cell death.ResultsFirst, ectopic JNK signaling-triggered cell death is enhanced by slik depletion whereas suppressed by Slik overexpression. Second, loss of slik activates JNK signaling, which results in enhanced apoptosis and impaired tissue homeostasis. In addition, genetic epistasis analysis suggests that Slik acts upstream of or in parallel to Hep to regulate JNK-mediated apoptotic cell death. Moreover, Slik is necessary and sufficient for preventing physiologic JNK signaling-mediated cell death in development. Furthermore, introduction of STK10, the human ortholog of Slik, into Drosophila restores slik depletion-induced cell death and compromised tissue homeostasis. Lastly, knockdown of STK10 in human cancer cells also leads to JNK activation, which is cancelled by expression of Slik.ConclusionsThis study has uncovered an evolutionarily conserved role of Slik/STK10 in blocking JNK signaling, which is required for cell death inhibition and tissue homeostasis maintenance in development.

Reduction of SPARC protects mice against NLRP3 inflammasome activation and obesity.

The comprehensive assessment of long-term effects of reducing intake of energy (CALERIE-II; NCT00427193) clinical trial established that caloric restriction (CR) in humans lowers inflammation. The identity and mechanism of endogenous CR-mimetics that can be deployed to control obesity-associated inflammation and diseases are not well understood. Our studies have found that 2 years of 14% sustained CR in humans inhibits the expression of the matricellular protein, secreted protein acidic and rich in cysteine (SPARC), in adipose tissue. In mice, adipose tissue remodeling caused by weight loss through CR and low-protein diet feeding decreased, while high-fat diet-induced (HFD-induced) obesity increased SPARC expression in adipose tissue. Inducible SPARC downregulation in adult mice mimicked CR's effects on lowering adiposity by regulating energy expenditure. Deletion of SPARC in adipocytes was sufficient to protect mice against HFD-induced adiposity, chronic inflammation, and metabolic dysfunction. Mechanistically, SPARC activates the NLRP3 inflammasome at the priming step and downregulation of SPARC lowers macrophage inflammation in adipose tissue, while excess SPARC activated macrophages via JNK signaling. Collectively, reduction of adipocyte-derived SPARC confers CR-like metabolic and antiinflammatory benefits in obesity by serving as an immunometabolic checkpoint of inflammation.

Gut Microbiota Metabolite 3-Indolepropionic Acid Directly Activates Hepatic Stellate Cells by ROS/JNK/p38 Signaling Pathways.

There has been a growing interest in studying the communication of gut microbial metabolites between the gut and the liver as liver fibrosis progresses. Although 3-Indolepropionic acid (IPA) is regarded as a clinically valuable gut metabolite for the treatment of certain chronic diseases, the effects of oral administration of IPA on hepatic fibrosis in different animal models have been conflicting. While some mechanisms have been proposed to explain these contradictory effects, the direct impact of IPA on hepatic fibrosis remains unclear. In this study, we found that IPA could directly activate LX-2 human hepatic stellate cells in vitro. IPA upregulated the expression of fibrogenic marker genes and promoted the features associated with HSCs activation, including proliferation and contractility. IPA also increased reactive oxygen species (ROS) in mitochondria and the expression of inflammation-related genes in LX-2 cells. However, when a ROS-blocking agent was used, these effects were reduced. p38 and JNK, the downstream signaling cascades of ROS, were found to be required for the activation of LX-2 induced by IPA. These findings suggest that IPA can directly activate hepatic stellate cells through ROS-induced JNK and p38 signaling pathways.

JNK- and Rel-Mediated Regulation of Inflammation and Neurotoxicity in Nauphoeta cinerea Exposed to Methylmercury and Monosodium Glutamate

Food contaminants are closely monitored to establish food safety profiles. Previously, we used the lobster cockroach to delineate the oxidative and antioxidant activities that characterize exposure to the organometallic cation (methylmercury; MeHg) sometimes found in fish and the common cooking seasoning (NaCl and MSG). Here, we further examined the mechanism of inflammatory response to MeHg, NaCl, and MSG, in an attempt to establish the crosstalk between redox and inflammatory signaling during heavy metal exposure in food. The insects were exposed to diets contaminated with MeHg, NaCl, and MSG for 21 days. Subsequently, mRNA from head homogenate was used to quantify the expression of a member of the Nox/Duox NADPH oxidases that produce reactive oxygen species (DUOX), as well as target genes of the JNK, TOLL, and UPD3/JAK/STAT pathways. MeHg exposure deregulated redox and inflammation-related genes, including upregulated DUOX in the MeHg group, upregulated Reaper, UPD3, and SOCS36E in the MeHg + NaCl group, and downregulated Reaper in the MeHg + MSG group. Both MeHg + NaCl and MeHg + MSG exposures upregulated PVF, EGR, and REL and downregulated FOXO levels. Our results suggest a role for the activation of the Nox/Duox NADPH oxidases, alongside JNK and Rel signaling during MeHg and MSG exposure, therefore offering insights for handling heavy metal poisoning and showcasing Nauphoeta cinerea as a viable model for understanding redox and inflammatory signaling.

Proteomic Profiling Identifies Distinct Regulation of Proteins in Obese Diabetic Patients Treated with Metformin.

Background: Obesity and type 2 diabetes mellitus (T2DM) are characterized by underlying low-grade chronic inflammation. Metformin has been used as the first line of therapy in T2DM as it decreases hepatic glucose production and glucose intestinal absorption, enhances insulin sensitivity and weight loss, and is known to ameliorate inflammation. The mechanisms through which metformin exerts its effect remain unclear. Proteomics has emerged as a unique approach to explore the biological changes associated with diseases, including T2DM. It provides insight into the circulating biomarkers/mediators which could be utilized for disease screening, diagnosis, and prognosis. Methods: This study evaluated the proteomic changes in obese (Ob), obese diabetics (OD), and obese diabetic patients on metformin (ODM) using a 2D DIGE MALDI-TOF mass spectrometric approach. Results: Significant changes in sixteen plasma proteins (15 up and 1 down, ANOVA, p ≤ 0.05; fold change ≥ 1.5) were observed in the ODM group when compared to the Ob and OD groups. Bioinformatic network pathway analysis revealed that the majority of these altered plasma proteins are involved in distinct pathways involving acute-phase response, inflammation, and oxidative response and were centered around HNF4A, ERK, JNK, and insulin signaling pathways. Conclusions: Our study provides important information about the possible biomarkers altered by metformin treatment in obese patients with and without T2DM. These altered plasma proteins are involved in distinct pathways involving acute-phase response, inflammation, and oxidative response and were centered around HNF4A, ERK, JNK, and insulin signaling pathways. The presented proteomic profiling approach may help in identifying potential biomarkers/mediators affected by metformin treatment in T2DM and inform the understanding of metformin's mechanisms of action.

MAPK Signaling Pathway Plays Different Regulatory Roles in the Effects of Boric Acid on Proliferation, Apoptosis, and Immune Function of Splenic Lymphocytes in Rats.

Boron is one of the essential trace elements in animals. Although boron supplementation can enhance immune function and promote cell proliferation, high-dose boron supplementation can negatively affect immune function and inhibit cell proliferation. Furthermore, its action pathway is unknown. In this study, ERK1/2, JNK, and p38MAPK signaling pathways were blocked using specific blockers to investigate the impact of low-dose and high-dose boron on proliferation, apoptosis, and immune function of lymphocytes, and the expression of genes related to cell proliferation and apoptosis in rats. The addition of 0.4 mmol/L boron did not affect the ratio of CD4+/CD8+ T cells (P>0.05), IgG and IFN-γ contents (P>0.05), the proliferation rate of lymphocytes (P>0.05), and mRNA and protein expressions of PCNA (P>0.05) in the spleen after ERK1/2 signal pathway was selectively inhibited. Moreover, the addition of 40 mmol/L boron did not affect the proportion of CD4+ T cells, contents of IgG and cytokines (IL-2 and IL-4), proliferation and apoptosis rates of lymphocytes, and expression of proliferation- and apoptosis-related genes in the spleen. Meanwhile, the addition of 0.4 mmol/l boron increased the ratio of CD4+/CD8+ T cells (P<0.05 or P<0.01), IFN-γ or IgG contents (P<0.05), and the proliferation rate of lymphocytes (P<0.05) in spleen after selective inhibition of JNK or p38MAPK signaling pathways, while the protein expression of Caspase-3 decreased (P<0.05 or P<0.01). Furthermore, 40 mmol/L boron decreased the proportion of lymphocyte subsets, cytokine contents, proliferation rate of lymphocytes, and mRNA and protein expressions of PCNA. In contrast, the mRNA and protein expressions of Caspase-3 and protein expression of Bax were increased. These results indicate that ERK1/2 signaling pathway mainly regulates the effects of low-dose and high-dose boron on proliferation, apoptosis, and immune function of splenic lymphocytes.

Meclizine moderates lipopolysaccharide-induced neuroinflammation in mice through the regulation of AKT/ NF-κβ/ERK/JNK signaling pathway

Neuroinflammation is identified as significant inflammatory reactions occurring in the central nervous system. Lipopolysaccharide (LPS) stimulates innate immune reactions and is used as an in vivo animal model for the investigation of inflammation. Meclizine (MCLZ) is a histamine antagonist with potential neuroprotective qualities. Forty adult male Swiss albino mice were divided into four groups (n = 10). Group 1 served as a control negative group. Groups 2–4 were injected with LPS (5 mg/kg; i.p). Group 2 served as LPS-control. Groups 3 & 4 were given MCLZ (12.5 & 25 mg/kg; p.o) respectively for 14 days. LPS administration resulted in significant neuroinflammation in mice as was revealed by significant inflammatory histopathological changes and positive immunohistochemical staining of glial fibrillary acidic proteins (GFAP) accompanied by significant elevations of brain tissue contents of interleukin-1-beta (IL-1β), tumor necrosis factor-alpha (TNF-α), nuclear factor kappa-beta (NF-κβ), protein kinase B (AKT), extracellular signal-regulated kinase (ERK) and C-Jun N-Terminal Kinases (JNK). MCLZ treatment significantly down-regulated all the aforementioned parameters in mice brains. Moreover, MCLZ treatment ameliorated the inflammatory histopathological changes and GFAP immunostaining in brain tissues. The current study identifies for the first time the protective anti-neuroinflammatory effects of MCLZ against LPS-induced neuroinflammation in mice. MCLZ protected against neuroinflammation via the amelioration of inflammatory histopathological changes as well as neuronal GFAP immunostaining and down-regulated the AKT/NF-κβ/ERK/JNK signaling pathway. MCLZ is anticipated as a potential protective candidate for the addition to the treatment protocol of neuroinflammation.

Par3L, a polarity protein, promotes M1 macrophage polarization and aggravates atherosclerosis in mice via p65 and ERK activation.

Proinflammatory M1 macrophages are critical for the progression of atherosclerosis. The Par3-like protein (Par3L) is a homolog of the Par3 family involved in cell polarity establishment. Par3L has been shown to maintain the stemness of mammary stem cells and promote the survival of colorectal cancer cells. In this study, we investigated the roles of the polar protein Par3L in M1 macrophage polarization and atherosclerosis. To induce atherosclerosis, Apoe-/- mice were fed with an atherosclerotic Western diet for 8 or 16 weeks. We showed that Par3L expression was significantly increased in human and mouse atherosclerotic plaques. In primary mouse macrophages, oxidized low-density lipoprotein (oxLDL, 50 μg/mL) time-dependently increased Par3L expression. In Apoe-/- mice, adenovirus-mediated Par3L overexpression aggravated atherosclerotic plaque formation accompanied by increased M1 macrophages in atherosclerotic plaques and bone marrow. In mouse bone marrow-derived macrophages (BMDMs) or peritoneal macrophages (PMs), we revealed that Par3L overexpression promoted LPS and IFNγ-induced M1 macrophage polarization by activating p65 and extracellular signal-regulated kinase (ERK) rather than p38 and JNK signaling. Our results uncover a previously unidentified role for the polarity protein Par3L in aggravating atherosclerosis and favoring M1 macrophage polarization, suggesting that Par3L may serve as a potential therapeutic target for atherosclerosis.