Anti-inflammatory effects of reticuline on the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathway in a mouse model of obesity-associated asthma.

BACKGROUND: Asthma associated with obesity is a chronic disease characterized by earlier airway remodeling, severe wheezing, and increased insensitivity to hormone therapy. Reticuline, a bioactive compound of Magnoliae Flos, exerts anti-inflammatory activity and can inhibit neutrophil recruitment. Thus, this study investigated the role of reticuline in obesity-related asthma. METHODS: The BALB/c mice fed a low-fat diet (LFD) and high-fat diet (HFD) were intranasally challenged with house dust mites (HDMs) or ovalbumin (OVA). Reticuline (0.25 mg/kg) was administrated into mice by intragastrical gavage. Airway hyper-responsiveness was examined after the final challenge. Body weight was measured, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected. The number of inflammatory cells in BALF was estimated. Histological changes were assessed by performing hematoxylin-eosin staining, and production of proinflammatory cytokines and IgE was examined by ELISA kits. Related pathways were studied with western blotting. RESULTS: Reticuline suppressed airway resistance and inflammatory infiltration in lung tissue and reduced inflammatory cell recruitment in BALF in obesity mice with asthma. Additionally, the levels of IL-17A, IL-1ß, IL-5, macrophage inflammatory protein 2, and regulated on activation, normal T cell expressed and secreted in the lung were reduced by reticuline. Mechanistically, reticuline inactivated the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways in obesity-related asthma. CONCLUSION: Reticuline alleviates airway inflammation in obesity-related asthma by inactivating the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways.

Loganin protects against myocardial ischemia-reperfusion injury by modulating oxidative stress and cellular apoptosis via activation of JAK2/STAT3 signaling.

BACKGROUND: Myocardial ischemia-reperfusion injury (MIRI) is a pathological process that follows immediate revascularization of myocardial infarction and is characterized by exacerbation of cardiac injury. Loganin, a monoterpene iridoid glycoside derived from Cornus officinalis Sieb. Et Zucc, can exert cardioprotective effects in cardiac hypertrophy and atherosclerosis. However, its role in ischemic heart disease remains largely unknown. METHODS: Considering that Janus kinase 2 (JAK2)/ signal transducer and activator of transcription 3 (STAT3) has a protective effect on the heart, we developed a mouse model of MIRI to investigate the potential role of this pathway in loganin-induced cardioprotection. RESULTS: Our results showed that treatment with loganin (20 mg/kg) prevented the enlargement of myocardial infarction, myocyte destruction, serum markers of cardiac injury, and deterioration of cardiac function induced by MIRI. Myocardium subjected to I/R treatment exhibited higher levels of oxidative stress, as indicated by an increase in malondialdehyde (MDA) and dihydroethidium (DHE) density and a decrease in total antioxidant capacity (T-AOC), glutathione (GSH), and superoxide dismutase (SOD), whereas treatment with loganin showed significant attenuation of I/R-induced oxidative stress. Loganin treatment also increased the expression of anti-apoptotic Bcl-2 and reduced the expression of caspase-3/9, Bax, and the number of TUNEL-positive cells in ischemic cardiac tissue. Moreover, treatment with loganin triggered JAK2/STAT3 phosphorylation, and AG490, a JAK2/STAT3 inhibitor, partially abrogated the cardioprotective effects of loganin, indicating the essential role of JAK2/STAT3 signaling in the cardioprotective effects of loganin. CONCLUSIONS: Our data demonstrate that loganin protects the heart from I/R injury by inhibiting I/R-induced oxidative stress and cellular apoptosis via activation of JAK2/STAT3 signaling.

Alpinetin inhibits neuroinflammation and neuronal apoptosis via targeting the JAK2/STAT3 signaling pathway in spinal cord injury.

BACKGROUND: A growing body of research shows that drug monomers from traditional Chinese herbal medicines have antineuroinflammatory and neuroprotective effects that can significantly improve the recovery of motor function after spinal cord injury (SCI). Here, we explore the role and molecular mechanisms of Alpinetin on activating microglia-mediated neuroinflammation and neuronal apoptosis after SCI. METHODS: Stimulation of microglia with lipopolysaccharide (LPS) to simulate neuroinflammation models in vitro, the effect of Alpinetin on the release of pro-inflammatory mediators in LPS-induced microglia and its mechanism were detected. In addition, a co-culture system of microglia and neuronal cells was constructed to assess the effect of Alpinetin on activating microglia-mediated neuronal apoptosis. Finally, rat spinal cord injury models were used to study the effects on inflammation, neuronal apoptosis, axonal regeneration, and motor function recovery in Alpinetin. RESULTS: Alpinetin inhibits microglia-mediated neuroinflammation and activity of the JAK2/STAT3 pathway. Alpinetin can also reverse activated microglia-mediated reactive oxygen species (ROS) production and decrease of mitochondrial membrane potential (MMP) in PC12 neuronal cells. In addition, in vivo Alpinetin significantly inhibits the inflammatory response and neuronal apoptosis, improves axonal regeneration, and recovery of motor function. CONCLUSION: Alpinetin can be used to treat neurodegenerative diseases and is a novel drug candidate for the treatment of microglia-mediated neuroinflammation.

3,5-Dicaffeoylquinic acid attenuates microglial activation-mediated inflammatory pain by enhancing autophagy through the suppression of MCP3/JAK2/STAT3 signaling.

Microglial activation in the spinal cord contributes to the development of inflammatory pain. Monocyte chemotactic protein 3 (MCP3) can induce microglial activation, resulting in increased pain sensitivity; however, the underlying mechanism remains poorly understood. 3,5-dicaffeoylquinic acid (3,5-DCQA) has shown protective effects against inflammation-related diseases, but the effect of 3,5-DCQA on microglial activation and inflammatory pain is not evaluated. This study aimed to investigate the effects of 3,5-DCQA on microglial activation-induced inflammatory pain. Furthermore, the underlying mechanism inhibited by 3,5-DCQA via MCP3 suppression was studied. To induce microglial activation, LPS was treated in BV2 microglial cells. The LPS-induced microglial activation and pro-inflammatory cytokines production were significantly reduced by 3,5-DCQA treatment in BV2 cells. Moreover, 3,5-DCQA suppressed LPS-induced MCP3 expression, resulting in reduced phosphorylation of JAK2/STAT3. Interestingly, the suppressed JAK2/STAT3 signaling enhanced autophagy induction in BV2 cells. The increased autophagy by 3,5-DCQA and knockout of MCP3 inhibited LPS-induced inflammatory response in BV2 cells. To establish the inflammatory pain, CFA was injected into the right paw of mice. The CFA-induced pain hypersensitivity and foot swelling were attenuated by the oral administration of 3,5-DCQA. Moreover, CFA-induced microglial activation was reduced and the autophagy markers were recovered in the spinal cord of 3,5-DCQA-administered mice. Similar results were observed in cultured primary microglia. Our findings indicate that 3,5-DCQA attenuates inflammation-mediated pain hypersensitivity by enhancing autophagy through inhibition of MCP3-induced JAK2/STAT3 signaling. Therefore, 3,5-DCQA could be a potential therapeutic agent for alleviating inflammatory pain.

The α7 nAChR allosteric modulator PNU-120596 amends neuroinflammatory and motor consequences of parkinsonism in rats: Role of JAK2/NF-κB/GSk3ß/ TNF-α pathway.

Parkinson's disease (PD) is the second most common neurodegenerative disorder and a leading cause of disability. The current gold standard for PD treatment, L-Dopa, has limited clinical efficacy and multiple side effects. Evidence suggests that activation of α7 nicotinic acetylcholine receptors (α7nAChRs) abrogates neuronal and inflammatory insults. Here we tested whether PNU-120596 (PNU), a type II positive allosteric modulator of α7 nAChR, has a critical role in regulating motor dysfunction and neuroinflammation correlated with the associated PD dysfunction. Neuroprotective mechanisms were investigated through neurobehavioral, molecular, histopathological, and immunohistochemical studies. PNU reversed motor incoordination and hypokinesia induced via the intrastriatal injection of 6-hydroxydopamine and manifested by lower falling latency in the rotarod test, short ambulation time and low rearing incidence in open field test. Tyrosine hydroxylase immunostaining showed a significant restoration of dopaminergic neurons following PNU treatment, in addition to histopathological restoration in nigrostriatal tissues. PNU halted striatal neuroinflammation manifested as a suppressed expression of JAK2/NF-κB/GSk3ß accompanied by a parallel decline in the protein expression of TNF-α in nigrostriatal tissue denoting the modulator anti-inflammatory capacity. Moreover, the protective effects of PNU were partially reversed by the α7 nAChR antagonist, methyllycaconitine, indicating the role of α7 nAChR modulation in the mechanism of action of PNU. This is the first study to reveal the positive effects of PNU-120596 on motor derangements of PD via JAK2/NF-κB/GSk3ß/ TNF-α neuroinflammatory pathways, which could offer a potential therapeutic strategy for PD.

Thymoquinone Induces Downregulation of BCR-ABL/JAK/STAT Pathway and Apoptosis in K562 Leukemia Cells.

OBJECTIVE: BCR ABL oncogene encodes the BCR-ABL chimeric protein, which is a constitutively activated non-receptor tyrosine kinase. The BCR-ABL oncoprotein is a key molecular basis for the pathogenesis of chronic myeloid leukemia (CML) via activation of several downstream signaling pathways including JAK/STAT pathway. Development of leukemia involves constitutive activation of signaling molecules including, JAK2, STAT3, STAT5A and STAT5B. Thymoquinone (TQ) is a bioactive constituent of Nigella sativa that has shown anticancer properties in various cancers. The present study aimed to evaluate the effect of TQ on the expression of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes and their consequences on the cell proliferation and apoptosis in K562 CML cells. METHODS: BCR-ABL positive K562 CML cells were treated with TQ. Cytotoxicity was determined by Trypan blue exclusion assay. Apoptosis assay was performed by annexin V-FITC/PI staining assay and analyzed by flow cytometry. Transcription levels of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes were evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Protein levels of JAK2 and STAT5 were determined by Jess Assay analysis. RESULTS: TQ markedly decreased the cell proliferation and induced apoptosis in K562 cells (P < 0.001) in a concentration dependent manner. TQ caused a significant decrease in the transcriptional levels of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes (P < 0.001). TQ induced a significant decrease in JAK2 and STAT5 protein levels (P < 0.001). CONCLUSION: our results indicated that TQ inhibited cell growth of K562 cells via downregulation of BCR ABL/ JAK2/STAT3 and STAT5 signaling and reducing JAK2 and STAT5 protein levels.

Curcumin inhibits proliferation and invasion of papillary thyroid carcinoma cells by inhibiting the JAK2 / STAT3 pathway.

PURPOSE: The purpose of this study was to analyze the function of curcumin to suppress the proliferative and invasive abilities of papillary thyroid carcinoma (PTC) through inhibiting the JAK2/STAT3 pathway. METHODS: After treatment of different doses of curcumin in TPC-1 and SW1736 cells, changes in viability, clonality, cell cycle, apoptosis, wound healing and invasion were determined. Western blot analyses were performed to detect protein levels of apoptosis-associated genes, JAK2 and STAT3 in TPC-1 and SW1736 cells treated with different doses of curcumin. RESULTS: Curcumin treatment dose-dependently reduced viability, clonality and metastatic ability in TPC-1 and SW1736 cells. After treatment of 10 µM or 20 µM curcumin, PTC cells were blocked in G2/M phase, and their apoptotic rate increased. Curcumin treatment downregulated Bcl-2 and upregulated Bax in PTC cells. In addition, curcumin treatment downregulated p-JAK2 and p-STAT3 in TPC-1 and SW1736 cells. CONCLUSIONS: Curcumin treatment blocks PTC cells to proliferate and invade via inhibiting the JAK2/STAT3 pathway.

Intrauterine hyperglycemia induces liver inflammation in mouse male offspring.

Gestational diabetes mellitus (GDM) is a common complication of pregnancy characterized by intrauterine hyperglycemia, which is often associated with a high risk of obesity and diabetes in the offspring. In this study, we established a GDM mouse model by intraperitoneal injection of streptozotocin to investigate the immuno-inflammatory responses in the liver of adult offspring. Glucose tolerance test (GTT) and insulin tolerance test (ITT) were employed to evaluate the glucose tolerance status. Hematoxylin-eosin staining was used to examine the histological changes in the liver. Quantitative real-timePCR (qRT-PCR) was applied to examine the mRNA expression of immune factors. Western blot and immunofluorescence analyses were used to examine the expression of target protein. Additionally, cell experiments were performed to validate the in vivo results. Compared to the control group, the area of fat vacuoles and the number of lymphocyte cells were significantly higher in the 20 weeks-old offspring of GDM mice. The elevated mRNA level of the pro-inflammatory cytokines IL-1ß, IL-6, IL-33 and immune receptors CD3 and CD36 were found in the liver of F1-GDM. The protein level of IL-6r and the phosphorylation of JAK2 and STAT3 were significantly up-regulated. Moreover, the mRNA level of IL-6, IL-1ß and IL-33 and the phosphorylation of JAK2 and STAT3 were also up-regulated in the hepatocyte treated with high concentration of glucose. Our results suggest that intrauterine hyperglycemia is associated with increased inflammation in the liver of adult male offspring.

Atezolizumab and blockade of LncRNA PVT1 attenuate cisplatin resistant ovarian cancer cells progression synergistically via JAK2/STAT3/PD-L1 pathway.

OBJECTIVE: To investigate the relationship between lncRNA PVT1(PVT1) level and PD-L1 expression and their functions in cisplatin resistant epithelial ovarian cancer (CREOC). METHODS: PVT1 and PD-L1 in ovarian cancer tissues were detected and analyzed. The cells proliferation, apoptosis, invasion abilities and potential mechanism were detected by cell functional experiments and western-blot assay, respectively. RESULTS: The average expressions of PVT1 and PD-L1 in CREOC tissues were significantly higher. The expression of PVT1 is positively associated with PD-L1 in CREOC. Higher expressions of PVT1 and PD-L1 indicated more malignant clinical behavior and shorter PFS and OS. Knockdown of PVT1 inhibited the proliferation and invasion and promote apoptosis for A2780cis cells, which may be related to decrease the expression of PD-L1 via repressing JAK2/STAT3 pathway. CONCLUSIONS: The synergistic therapeutic strategy using LncRNA PVT1-targeted therapy and immune checkpoint blockade of PD-L1 warrant study further for ovarian cancer patients with cisplatin resistant recurrence.

Activation of alpha7 nicotinic acetylcholine receptor protects bovine endometrial tissue against LPS-induced inflammatory injury via JAK2/STAT3 pathway and COX-2 derived prostaglandin E2.

Bovine endometritis is one of the major postpartum diseases associated with infertility and subfertility, decreasing the benefit of dairy industry. It is important to develop alternate therapies for endometritis in the context of drug residues in the milk and hormone disorder in the estrous cycle. α7 nicotine acetylcholine receptor has been identified as the core of 'cholinergic anti-inflammatory pathway (CAP)', which is a potential drug target to inflammatory diseases. However, there has been still no study on its anti-inflammatory effects and mechanism on lipopolysaccharide (LPS)-induced bovine endometritis. This study aimed to demonstrate the underlying anti-inflammatory effects and mechanism of α7-nACh receptor on LPS-induced inflammation in bovine endometrial tissues cultured in vitro. The results suggested that activation of α7-nACh receptor significantly suppressed the mRNA expression levels of interleukin 1ß (IL-1ß), IL-6, IL-8, and tumor necrosis factor alpha (TNF-α) in bovine endometrial tissues. Western blot and enzyme-linked immunosorbent assay (ELISA) detection results showed that activation of α7-nACh receptor inhibited LPS-induced phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). Moreover, α7-nACh receptor agonist decreased the expression of cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase-1(mPGES-1), as well as prostaglandin E2 (PGE2) secretion. Interestingly, in COX-2 inhibition experiment, activation of α7-nACh receptor increased COX-2 expression and PGE2 production, compared with COX-2 inhibitor treatment. In conclusion, activation of the cholinergic system through α7-nACh receptor agonist has suppressed inflammation of bovine endometrial tissues via JAK2/STAT3 pathway and potential COX-2-derived PGE2.

Nitidine chloride suppresses epithelial-mesenchymal transition and stem cell-like properties in glioblastoma by regulating JAK2/STAT3 signaling.

Glioblastoma is the most aggressive and common intracranial malignant tumor, and the prognosis is still poor after various treatments. Based on the poor prognosis of glioma, new drugs that suppress the rapid progression and aggressive growth of glioma are urgently needed. It has been reported that nitidine chloride (NC) can inhibit tumor growth and epithelial-mesenchymal transition (EMT), and EMT is associated with cancer stem cell properties. The present study aimed to investigate the inhibitory effect of NC on the EMT process and stem cell-like properties in glioma cells. The results showed that the migration and invasion abilities in U87 and LN18 glioma cells were significantly increased after the induction of EMT and these effects were inhibited by NC in a concentration-dependent manner. NC treatment decreased the expression of EMT markers in glioma cells and self-renewal capacity of glioma stem-like cells. We demonstrated that these effects of NC were achieved via JAK2/STAT3 signaling. Taken together, these results indicate that NC inhibits the EMT process and glioma stem-like properties via JAK2/STAT3 signaling pathway, suggesting that NC may be a potential anti-glioma drug.

Cucurbitacin B exhibits antitumor effects on CD133+ HepG2 liver cancer stem cells by inhibiting JAK2/STAT3 signaling pathway.

Cancer stem cells (CSCs), a crucial cancer cell subpopulation, possess stemness phenotypic characteristics. Cucurbitacin B (CuB), a tetracyclic triterpenoid isolated from Cucurbitaceae, exerts widely pharmacological activities in many diseases. The aim of this study was to enrich, identify liver CSCs and investigate antitumor effects of CuB as well as explore the underlying molecular mechanisms in these liver CSCs. HepG2 cell lines were used for the enrichment of liver CSCs by serum-free medium culture and magnetic-activated cell sorting. The CSC characteristics were analyzed by immunofluorescent staining, sphere-forming, western blot and xenograft tumorigenicity assay. CuB' antitumor effects and underlying molecular mechanism were measured by cell counting kit-8, colony formation, sphere-forming, cell cycle, xenograft and western blot assay. Our results showed that we could enrich 97.29% CD133+ HepG2 cells, which possessed CSC characteristics including re-renewal capacity, proliferative ability, sorafenib resistance, overexpressed stemness-related molecules and enhanced tumorigenic potential. Furthermore, we also found that CuB inhibited cell viability, sphere formation, colony formation and arrested cell cycle at G2/M phase as well as sensitized CD133+ HepG2 cells to sorafenib in vitro and in vivo. Western blot assay indicated that CuB inhibited expression levels of cyclin B1, CDK1, CD133, p-JAK2 and p-STAT3. In conclusion, our findings indicated that CuB could exhibit antitumor effects on CD133+ HepG2 CSCs by inhibiting the Janus kinase 2/signal transducers and activators of transcription-3 signaling pathway, expanding basic and preclinical investigations on liver CSCs.

LIF maintains mouse embryonic stem cells pluripotency by modulating TET1 and JMJD2 activity in a JAK2-dependent manner.

The LIF-JAK2-STAT3 pathway is the central signal transducer that maintains undifferentiated mouse embryonic stem cells (mESCs), which is achieved by the recruitment of activated STAT3 to the master pluripotency genes and activation of the gene transcriptions. It remains unclear, however, how the epigenetic status required for the master gene transcriptions is built into LIF-treated mESC cultures. In this study, Jak2, but not Stat3, in the LIF canonical pathway, establishes an open epigenetic status in the pluripotency gene promoter regions. Upon LIF activation, cytosolic JAK2 was translocalized into the nucleus of mESCs, and reduced DNA methylation (5mC levels) along with increasing DNA hydroxymethylation (5hmC) in the pluripotent gene (Nanog/Pou5f1) promoter regions. In addition, the repressive histone codes H3K9m3/H3K27m3 were reduced by JAK2. Activated JAK2 directly interacted with the core epigenetic enzymes TET1 and JMJD2, modulating its activity and promotes the DNA and histone demethylation, respectively. The JAK2 effects were attained by tyrosine phosphorylation on the epigenetic enzymes. The effects of JAK2 phosphorylation on the enzymes were diverse, but all were merged to the epigenetic signatures associated with open DNA/chromatin structures. Taken together, these results reveal a previously unrecognized epigenetic regulatory role of JAK2 as an important mediator of mESC maintenance.

Mutant erythropoietin enhances white matter repair via the JAK2/STAT3 and C/EBPß pathway in middle-aged mice following cerebral ischemia and reperfusion.

Previous studies have indicated that EPO maintains the M2 microglia phenotype that contributes to white matter repair after ischemic stroke in young mice (2 months old). However, the underlying mechanisms that regulate microglial polarization are poorly defined. This study investigated the neuroprotective effects of nonerythropoietic mutant EPO (MEPO) on white matter and the underlying mechanism in middle-aged (9-month-old) male mice following cerebral ischemia. Middle-aged male C57 BL/6 mice were treated with MEPO (5000 IU/kg) or vehicle after middle cerebral artery occlusion (MCAO) and reperfusion. The specific inhibitor AG490 was used to block the JAK2/STAT3 pathway. Neurological function was assessed by beam walking and adhesive removal tests. Immunofluorescence staining and western blotting were used to assess the severity of white matter injury, phenotypic changes in the microglia and the expression of the signaling molecules. MEPO significantly improved neurobehavioral outcomes, alleviated brain tissue loss, and ameliorated white matter injury after MCAO compared with the vehicle group. Moreover, MEPO promoted oligodendrogenesis by shifting microglia toward M2 polarization by promoting JAK2/STAT3 activation and inhibiting the expression of C/EBPß at 14 days after cerebral ischemia-reperfusion. However, the MEPO's effect on microglial M2 polarization and oligodendrogenesis was largely suppressed by AG490 treatment. Collectively, these data indicate that MEPO treatment improves white matter integrity after cerebral ischemia, which may be partly explained by MEPO facilitating microglia toward the beneficial M2 phenotype to promote oligodendrogenesis via JAK2/STAT3 and the C/EBPß signaling pathway. This study provides novel insight into MEPO treatment for ischemic stroke.

Notoginsenoside R1 counteracts mesenchymal stem cell-evoked oncogenesis and doxorubicin resistance in osteosarcoma cells by blocking IL-6 secretion-induced JAK2/STAT3 signaling.

Tumor microenvironment is a critical participant in the initiation, progression and drug resistance of carcinomas, including osteosarcoma. Notoginsenoside R1 (NGR1) is a proverbial active ingredient of the traditional Chinese medicine Panax notoginseng (PN) and possess undeniable roles in several cancers. Nevertheless, its function in osteosarcoma and tumor microenvironment remains elusive. In the current study, exposure to NGR1 dose-dependently inhibited osteosarcoma cell viability and migration, and induced apoptosis. Furthermore, osteosarcoma cells that were incubated with conditioned medium (CM) from bone marrow mesenchymal stem cells (BMSCs) exhibited greater proliferation, migration capacity and MMP-2 and MMP-9 expression relative to control cells, which was reversed when BMSCs were treated with NGR1. Notably, administration with NGR1 antagonized CM-evoked doxorubicin resistance in osteosarcoma cells by decreasing cell viability and increasing cell apoptosis and caspase-3/9 activity. Mechanically, NGR1 suppressed IL-6 secretion from BMSCs, as well as the subsequent activation of the JAK2/STAT3 signaling in osteosarcoma cells. In addition, blocking the JAK2 pathway by its antagonist AG490 reversed CM-induced osteosarcoma cell proliferation, migration and doxorubicin resistance. Moreover, exogenous supplementation with IL-6 engendered not only the reactivation of the JAK2/STAT3 signaling but also muted NGR1-mediated efficacy against osteosarcoma cell malignancy and doxorubicin resistance. Collectively, NGR1 may directly restrain osteosarcoma cell growth and migration, or indirectly antagonize MSC-evoked malignancy and drug resistance by interdicting IL-6 secretion-evoked activation of the JAK2/STAT3 pathway. Consequently, the current study may highlight a promising therapeutic strategy against osteosarcoma by regulating tumor cells and the tumor microenvironment.

Fucoidan from Fucus vesiculosus attenuates doxorubicin-induced acute cardiotoxicity by regulating JAK2/STAT3-mediated apoptosis and autophagy.

Doxorubicin (DOX) is well-known for its potent antitumor activity but limited by its multiple and serious adverse effects. A major adverse effect is acute cardiotoxicity; yet, its mechanism has not been elucidated. Fucoidan is a multifunctional and nontoxic polysaccharide that is widely studied because of its favorable biological activities and safety. Hence, we proposed that fucoidan may play a protective role in DOX-induced acute cardiotoxicity without causing additional side effects. Sprague-Dawley rats were injected intraperitoneally with a single high dose of DOX to induce acute cardiac injury. Fucoidan was administered orally before DOX injection and AG490, a JAK2 inhibitor, was applied to verify the participation of the JAK2/STAT3 pathway. In vitro, H9C2 cells were treated with the same drugs at different concentrations and intervention times. in vivo and in vitro results demonstrated that DOX administration induced myocardial damage accompanied by acceleratory apoptosis and deficient autophagy in heart tissues or cells, which could be significantly improved by fucoidan supplement. AG490 partly abolished the cardioprotective effects of fucoidan, suggesting the involvement of JAK2 signaling. Additionally, western blotting revealed DOX-induced JAK2/STAT3 pathway activation, which was enhanced by fucoidan and weaken by AG490. Hence, fucoidan exerted a favorable effect on DOX-induced cardiotoxicity by enhancing autophagy and suppressing apoptosis in a JAK2/STAT3-dependent manner, which may provide a promising and novel therapeutic strategy against negative chemotherapy-induced effects.

microRNA-1906 protects cerebral ischemic injury through activating Janus kinase 2/signal transducer and activator of transcription 3 pathway in rats.

This study aimed to investigate the effects of miR-1906 on cerebral ischemic injury and its underlying mechanisms. After 24 h of reperfusion, neurological deficit scores, brain water content and infarct volume were measured. Neuronal apoptosis was detected by using terminal dexynucleotidyl transferase-mediated dUTP nick end labeling assay. Hematoxylin-eosin staining was used to evaluate the histopathological damage of neurons. The expression of miR-1906 was detected by qRT-PCR. And the expressions of Bax, Bcl-2, caspase-3, Janus kinase 2 (JAK2), p-JAK2, signal transducer and activator of transcription 3 (STAT3) and p-STAT3 were measured by western blot. Furthermore, the levels of tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß) and IL-6 were measured by ELISA. We found that miR-1906 expression was significantly decreased in the cerebral ischemia injury rats. miR-1906 decreased neurological score, infarct volume, brain water content, neuronal apoptosis and inflammatory factors (TNF-α, IL-6 and IL-1ß) expression. In addition, miR-1906 promoted the phosphorylation of JAK2 and STAT3. After treating with JAK2/STAT3 pathway inhibitor AG490, the phosphorylation of JAK2 and STAT3 was inhibited and the effects of miR-1906 on neurological score, infarct volume, brain water content, neuronal apoptosis and inflammatory factors were reversed. miR-1906 could protect cerebral ischemic injury through activating the JAK2/STAT3 pathway in rats.

The inhibition of the breast cancer by PPARγ agonist pioglitazone through JAK2/STAT3 pathway.

Breast cancer, especially triple-negative breast cancer, is one of the deadliest cancers in women. To date, there is a lack of a good therapeutic regimen for it. PPARγ has been reported to be a tumor suppressor and could be activated by many agonists involved in cancer inhibition. Therefore, the expression of PPARγ in breast cancer was analyzed by online software UALCAN whose data were from the TCGA database. The results revealed that the PPARγ expression was reduced in breast cancer tissues. Furthermore, the methylation in the PPARγ promoter was also assayed and the results indicated that the methylation level in the PPARγ promoter in breast cancer tissue was higher than that in normal tissue. In order to verify the methylation in promoter involved in the regulation of gene PPARγ expression, the 5'-Aza and fluorescence assays were performed and the results proved that methylation in promoter participated in gene PPARγ expression regulation. Pioglitazone, a PPARγ agonist, still was not investigated in breast cancer. Therefore, the effects of pioglitazone on breast cancer cells were tested by cell viability, scratch and transwell assays, and results indicated that the pioglitazone has the inhibition effect on the proliferation and migration of breast cancer cells by PPARγ which was correlated with the JAK2/STAT3 pathway. In order to further confirm the inhibition effect of pioglitazone on breast cancer in vivo, the nude mice model was administrated by gavage with pioglitazone. And the results indicated that pioglitazone could inhibit the growth of breast cancer in the PPARγ overexpression group in vivo. In summary, the expression of gene PPARγ was decreased in breast cancer tissues, which was correlated with its methylation in the promoter region. Moreover, pioglitazone could exert its inhibition on breast cancer proliferation and migration by the JAK2/STAT3 pathway.

Levetiracetam Reduces Early Inflammatory Response After Experimental Intracerebral Hemorrhage by Regulating the Janus Kinase 2 (JAK2)-Signal Transducer and Activator of Transcription 3 (STAT3) Signaling Pathway.

BACKGROUND Levetiracetam (LEV) is an antiepileptic drug that promotes recovery of neurological function by alleviating inflammatory reactions. However, it is not known whether it can improve secondary brain injury after intracerebral hemorrhage (ICH). The aim of this study was to determine whether LEV can reduce early inflammatory response after ICH in rats. MATERIAL AND METHODS An in vitro model of early inflammation was created by treating microglia cells with lipopolysaccharide (LPS). After exposure to various concentrations of LEV, the expression levels of NF-kappaB and STAT3 and inflammatory factors such as interleukin (IL)-1ß and tumor necrosis factor (TNF)-alpha in microglia were detected. In vivo, autologous blood was used to induce the rat ICH model. The effects of LEV on post-cerebral hemorrhagic inflammatory response were examined using neurobehavioral tests, FJC staining, brain water content testing, and analysis of protein expression levels of NF-kappaB, JAK2, STAT3, and inflammatory factors. RESULTS LEV treatment significantly reduced the expression of inflammatory factors and protein expression levels of NF-kappaB and STAT3 in LPS-treated microglia cells (P<0.05). In male Sprague-Dawley (SD) rats, LEV treatment markedly decreased the volume of hematoma and the number of degenerative neurons (P<0.05). It also improved the neurological function and relieved brain edema. The protein expression levels of NF-kappaB, JAK2, and STAT3 were significantly lower in the ICH+LEV group than in the control group (P<0.05). CONCLUSIONS Our study suggests that treatment with LEV alleviates early inflammatory responses induced by ICH. Mechanistically, LEV inhibited the JAK2-STAT3 signaling pathway and reduced neuronal injury around the hematoma, and ameliorated brain edema, all of which promoted recovery of nerve function after hemorrhage.

JAK2/STAT3 involves oxidative stress-induced cell injury in N2a cells and a rat MCAO model.

Purpose: In this study, we sought to test the hypothesis that oxidative stress injury in ischemic brains and H2O2-treated mouse neuroblastoma Neuro-2a cells (N2a) was related to STAT3 activation.Materials and methods: Rat middle cerebral artery occlusion (MCAO) model and H2O2-treated mouse neuroblastoma Neuro-2a cells (N2a) were used to investigate the relationship between oxidative stress injury and STAT3 activation.Results: 8-Hydroxy-2'-deoxyguanosine (8-OHdG) content and STAT3 protein phosphorylation level were significantly increased after cerebral ischemia-reperfusion. H2O2 treatment inhibited the cell viability, induced the apoptosis, and further raised pSTAT3 protein level in N2a cells. Moreover, the addition of AG490, the protein inhibitor of JAK2, significantly alleviated cerebral ischemic damage in vivo and H2O2-induced injury in vitro, and JAK2 siRNA also alleviated H2O2-induced injury in N2a cell.Conclusions: JAK2/STAT3 pathway may play a crucial role in mediating reactive oxidative species (ROS)-induced cell injury in rat middle cerebral artery occlusion (MCAO) model and N2a cells. ROS scavenging and down-regulation of STAT3 activation might be a candidate design of therapeutic strategies against oxidative stress-related neurological diseases.