Agrimonia pilosa Ledeb Root Extract: Anti-Inflammatory Activities of the Medicinal Herb in LPS-Induced Inflammation.

Inflammation regulation is essential for maintaining healthy functions and normal homeostasis of the body. Porphyromonas gingivalis (P. gingivalis) is a gram-negative anaerobic bacterium and a major pathogen that causes oral inflammation and other systemic inflammations. This study aims to examine the anti-inflammatory effects of Agrimonia pilosa Ledeb root extracts (APL-ME) in Porphyromonas gingivalis LPS-induced RAW 264.7 cells and find anti-inflammatory effect compounds of APL-ME. The anti-inflammatory effects of APL-ME were evaluated anti-oxidant activity, cell viability, nitrite concentration, pro-inflammatory cytokines (interleukin-1[Formula: see text], interleukin-6, tumor necrosis factor (TNF)-[Formula: see text], and anti-inflammatory cytokine (interleukin-10 (IL-10)). Also, Inflammation related genes and proteins, cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), expression were decreased by APL-ME and mitogen-activated protein kinase (MAPK) signaling proteins expression was regulated by APL-ME. Liquid chromatography-mass spectrometer (LC/MS)-MS analysis results indicated that several components were detected in APL-ME. Our study indicated that APL-ME suppressed nitrite concentrations, pro-inflammatory cytokines such as IL-1[Formula: see text], IL-6 and TNF-[Formula: see text] in P. gingivalis LPS induced RAW 264.7 cells. However, IL-10 expression was increased by ALP-ME. In addition, protein expressions of COX-2 and iNOS were inhibited APL-ME extracts dose-dependently. According to these results, APL-ME has anti-inflammatory effects in P. gingivalis LPS induced RAW 264.7 cells.

Antidepressant and Anti-Neuroinflammatory Effects of Bangpungtongsung-San.

Bangpungtongsung-san (BTS) is a traditional Korean medicine consisting of 18 herbs, some which have antidepressant effects. Here, we used an animal model of reserpine-induced depression and lipopolysaccharide (LPS)-stimulated BV2 microglia to assess the antidepressant and anti-neuroinflammatory effects of BTS. Aside from a control group, C57BL/6 mice were administered reserpine (0.5 mg/kg) daily for 10 days via intraperitoneal injection. BTS (100, 300, or 500 mg/kg), vehicle (PBS), or fluoxetine (FXT, 20 mg/kg) was administered orally 1 h before reserpine treatment. Following treatment, a forced swimming test (FST), tail suspension test (TST), and open field test (OFT) were performed, and immobility time and total travel distance were measured. Administration of BTS not only reduced immobility time in the FST and TST but also significantly increased the total travel distance in the OFT. Furthermore, reserpine-treated mice showed significantly elevated serum levels of corticosterone, a stress hormone; however, treatment with BTS significantly reduced corticosterone levels, similar to FXT treatment. Serotonin in reserpine-treated mice was significantly reduced compared to that in control mice, while BTS mice exhibited increased serotonin levels. BTS mice showed increased expression of brain-derived neurotrophic factor (BDNF) and a higher ratio of phosphorylated cAMP response element-binding protein (p-CREB) to CREB (p-CREB/CREB) in the hippocampus. Additionally, reserpine-treated mice exhibited significantly elevated mRNA levels of pro-inflammatory cytokines, but BTS mice showed reduced mRNA levels of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in the hippocampus. To further demonstrate the anti-neuroinflammatory effects of BTS in vitro, we examined its anti-neuroinflammatory and neuroprotective effects in lipopolysaccharide (LPS)-stimulated BV2 microglia. BTS significantly reduced the levels of NO, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, TNF-α, IL-1ß, and IL-6 in a dose-dependent manner via a decrease in the expression of nuclear factor (NF)-κB p65. Furthermore, the neuroprotective factor heme oxygenase-1 (HO-1) was upregulated via the nuclear factor-E2-related factor 2 (NRF2)/CREB pathway. Taken together, our data suggest that BTS has considerable potential as an anti-neuroinflammation and antidepressant agent, as it has clear effects on depressive behaviors and associated factors caused by reserpine-induced depression.

Cordyceps militaris Exerts Anticancer Effect on Non-Small Cell Lung Cancer by Inhibiting Hedgehog Signaling via Suppression of TCTN3.

This study aimed to investigate the effect of Cordyceps militaris extract on the proliferation and apoptosis of non-small cell lung cancer (NSCLC) cells and determine the underlying mechanisms. We performed a CCK-8 assay to detect cell proliferation, detection of morphological changes through transmission electron microscopy (TEM), annexin V-FITC/PI double staining to analyze apoptosis, and immunoblotting to measure the protein expression of apoptosis and hedgehog signaling-related proteins, with C militaris treated NSCLC cells. In this study, we first found that C militaris reduced the viability and induced morphological disruption in NSCLC cells. The gene expression profiles indicated a reprogramming pattern of genes and transcription factors associated with the action of TCTN3 on NSCLC cells. We also confirmed that the C militaris-induced inhibition of TCTN3 expression affected the hedgehog signaling pathway. Immunoblotting indicated that C militaris-mediated TCTN3 downregulation induced apoptosis in NSCLC cells, involved in the serial activation of caspases. Moreover, we demonstrated that the C militaris negatively modulated GLI1 transcriptional activity by suppressing SMO/PTCH1 signaling, which affects the intrinsic apoptotic pathway. When hedgehog binds to the PTCH1, SMO dissociates from PTCH1 inhibition at cilia. As a result, the active GLI1 translocates to the nucleus. C militaris clearly suppressed GLI1 nuclear translocation, leading to Bcl-2 and Bcl-xL down-regulation. These results suggested that C militaris induced NSCLC cell apoptosis, possibly through the downregulation of SMO/PTCH1 signaling and GLI1 activation via inhibition of TCTN3. Taken together, our findings provide new insights into the treatment of NSCLC using C militaris.

Overexpression of TC-PTP in murine epidermis attenuates skin tumor formation.

T-cell protein tyrosine phosphatase (TC-PTP), encoded by Ptpn2, has been shown to function as a tumor suppressor during skin carcinogenesis. In the current study, we generated a novel epidermal-specific TC-PTP-overexpressing (K5HA.Ptpn2) mouse model to show that TC-PTP contributes to the attenuation of chemically induced skin carcinogenesis through the synergistic regulation of STAT1, STAT3, STAT5, and PI3K/AKT signaling. We found overexpression of TC-PTP increased epidermal sensitivity to DMBA-induced apoptosis and it decreased TPA-mediated hyperproliferation, coinciding with reduced epidermal thickness. Inhibition of STAT1, STAT3, STAT5, or AKT reversed the effects of TC-PTP overexpression on epidermal survival and proliferation. Mice overexpressing TC-PTP in the epidermis developed significantly reduced numbers of tumors during skin carcinogenesis and presented a prolonged latency of tumor initiation. Examination of human papillomas and squamous cell carcinomas (SCCs) revealed that TC-PTP expression was significantly reduced and TC-PTP expression was inversely correlated with the increased grade of SCCs. Our findings demonstrate that TC-PTP is a potential therapeutic target for the prevention of human skin cancer given that it is a major negative regulator of oncogenic signaling.

The Flower Extract of Abelmoschus manihot (Linn.) Increases Cyclin D1 Expression and Activates Cell Proliferation.

Abelmoschus manihot (Linn.) is a medicinal herbal plant that is commonly used to treat chronic kidney disease and hepatitis. However, its effect on cell proliferation has not been clearly revealed. In this report, we sought to determine the effect of the flower extract of A. manihot (FA) on cell proliferation. Based on our findings, FA increased the proliferation of human diploid fibroblast (HDF) and HEK293 cells. Through cell cycle analysis, FA was found to increase the number of HDF cells in the S phase and G2/M phase. FA also increased the expression of cyclin D1 and enhanced the migration of HDF cells. By administering FA to HDF cells with ≥30 passages, a decrease in the number of senescence-associated ß galactosidase-positive cells was observed, thereby indicating that FA can ameliorate cellular senescence. Collectively, our findings indicate that FA increases cyclin D1 expression and regulates cell proliferation.

Proteomic analyses reveal that ginsenoside Rg3(S) partially reverses cellular senescence in human dermal fibroblasts by inducing peroxiredoxin.

BACKGROUND: The cellular senescence of primary cultured cells is an irreversible process characterized by growth arrest. Restoration of senescence by ginsenosides has not been explored so far. Rg3(S) treatment markedly decreased senescence-associated ß-galactosidase activity and intracellular reactive oxygen species levels in senescent human dermal fibroblasts (HDFs). However, the underlying mechanism of this effect of Rg3(S) on the senescent HDFs remains unknown. METHODS: We performed a label-free quantitative proteomics to identify the altered proteins in Rg3(S)-treated senescent HDFs. Upregulated proteins induced by Rg3(S) were validated by real-time polymerase chain reaction and immunoblot analyses. RESULTS: Finally, 157 human proteins were identified, and variable peroxiredoxin (PRDX) isotypes were highly implicated by network analyses. Among them, the mitochondrial PRDX3 was transcriptionally and translationally increased in response to Rg3(S) treatment in senescent HDFs in a time-dependent manner. CONCLUSION: Our proteomic approach provides insights into the partial reversing effect of Rg3 on senescent HDFs through induction of antioxidant enzymes, particularly PRDX3.

Stereoisomer-specific ginsenoside 20(S)-Rg3 reverses replicative senescence of human diploid fibroblasts via Akt-mTOR-Sirtuin signaling.

BACKGROUND: The replicative senescence of human dermal fibroblasts (HDFs) is accompanied by growth arrest. In our previous study, the treatment of senescent HDFs with Rg3(S) lowered the intrinsic reactive oxygen species (ROS) levels and reversed cellular senescence by inducing peroxiredoxin-3, an antioxidant enzyme. However, the signaling pathways involved in Rg3(S)-induced senescence reversal in HDFs and the relatedness of the stereoisomer Rg3(R) in corresponding signaling pathways are not known yet. METHODS: We performed senescence-associated ß-galactosidase and cell cycle assays in Rg3(S)-treated senescent HDFs. The levels of ROS, adenosine triphosphate (ATP), and cyclic adenosine monophosphate (cAMP) as well as the mitochondrial DNA copy number, nicotinamide adenine dinucleotide (NAD)+/1,4-dihydronicotinamide adenine dinucleotide (NADH) ratio, and NAD-dependent sirtuins expression were measured and compared among young, old, and Rg3(S)-pretreated old HDFs. Major signaling pathways of phosphatidylinositol 3-kinase/Akt, 5' adenosine monophosphate-activated protein kinase (AMPK), and sirtuin 1/3, including cell cycle regulatory proteins, were examined by immunoblot analysis. RESULTS: Ginsenoside Rg3(S) reversed the replicative senescence of HDFs by restoring the ATP level and NAD+/NADH ratio in downregulated senescent HDFs. Rg3(S) recovered directly the cellular levels of ROS and the NAD+/NADH ratio in young HDFs inactivated by rotenone. Rg3(S) mainly downregulated phosphatidylinositol 3-kinase/Akt through the inhibition of mTOR by cell cycle regulators like p53/p21 in senescent HDFs, whereas Rg3(R) did not alter the corresponding signaling pathways. Rg3(S)-activated sirtuin 3/PGC1α to stimulate mitochondrial biogenesis. CONCLUSION: Cellular molecular analysis suggests that Rg3(S) specifically reverses the replicative senescence of HDFs by modulating Akt-mTOR-sirtuin signaling to promote the biogenesis of mitochondria.

Cordyceps militaris induces apoptosis in ovarian cancer cells through TNF-α/TNFR1-mediated inhibition of NF-κB phosphorylation.

BACKGROUND: Cordyceps militaris (L.) Fr. (C. militaris) exhibits pharmacological activities, including antitumor properties, through the regulation of the nuclear factor kappa B (NF-κB) signaling. Tumor Necrosis Factor (TNF) and TNF-α modulates cell survival and apoptosis through NF- κB signaling. However, the mechanism underlying its mode of action on the NF-κB pathway is unclear. METHODS: Here, we analyzed the effect of C. militaris extract (CME) on the proliferation of ovarian cancer cells by confirming viability, morphological changes, migration assay. Additionally, CME induced apoptosis was determined by apoptosis assay and apoptotic body formation under TEM. The mechanisms of CME were determined through microarray, immunoblotting and immunocytochemistry. RESULTS: CME reduced the viability of cells in a dose-dependent manner and induced morphological changes. We confirmed the decrease in the migration activity of SKOV-3 cells after treatment with CME and the consequent induction of apoptosis. Immunoblotting results showed that the CME-mediated upregulation of tumor necrosis factor receptor 1 (TNFR1) expression induced apoptosis of SKOV-3 cells via the serial activation of caspases. Moreover, CME negatively modulated NF-κB activation via TNFR expression, suggestive of the activation of the extrinsic apoptotic pathway. The binding of TNF-α to TNFR results in the disassociation of IκB from NF-κB and the subsequent translocation of the active NF-κB to the nucleus. CME clearly suppressed NF-κB translocation induced by interleukin (IL-1ß) from the cytosol into the nucleus. The decrease in the expression levels of B cell lymphoma (Bcl)-xL and Bcl-2 led to a marked increase in cell apoptosis. CONCLUSION: These results suggest that C. militaris inhibited ovarian cancer cell proliferation, survival, and migration, possibly through the coordination between TNF-α/TNFR1 signaling and NF-κB activation. Taken together, our findings provide a new insight into a novel treatment strategy for ovarian cancer using C. militaris.

Cordycepin inhibits human ovarian cancer by inducing autophagy and apoptosis through Dickkopf-related protein 1/ß-catenin signaling.

Cordycepin, the major active component from Cordyceps militaris, has been reported to significantly inhibit some types of cancer; however, its effects on ovarian cancer are still not well understood. In this study, we treated human ovarian cancer cells with different doses of cordycepin and found that it dose-dependently reduced ovarian cancer cell viability, based on Cell counting kit-8 reagent. Immunoblotting showed that cordycepin increased Dickkopf-related protein 1 (Dkk1) levels and inhibited ß-catenin signaling. Atg7 knockdown in ovarian cancer cells significantly inhibited cordycepin-induced apoptosis, whereas ß-catenin overexpression abolished the effects of cordycepin on cell death and proliferation. Furthermore, we found that Dkk1 overexpression by transfection downregulated the expression of c-Myc and cyclin D1. siRNA-mediated Dkk1 silencing downregulated the expression of Atg8, beclin, and LC3 and promoted ß-catenin translocation from the cytoplasm into the nucleus. These results suggest that cordycepin inhibits ovarian cancer cell growth, possibly through coordinated autophagy and Dkk1/ß-catenin signaling. Taken together, our findings provide new insights into the treatment of ovarian cancer using cordycepin.

LNX1 contributes to tumor growth by down-regulating p53 stability.

The well-known tumor suppressor p53 inhibits the formation of various cancers by inducing cell cycle arrest and apoptosis. Although p53 mutations are commonly found in many cancers, p53 is functionally inactivated in tumor cells that retain wild-type p53. Here, we show that the ligand of numb protein X1 (LNX1) inhibited p53-dependent transcription by decreasing the half-life of p53. We generated LNX1 knockout (KO) cells in p53 wild-type cancer cells (A549, HCT116, and MCF7) using the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 gene-editing system. LNX1 KO activated p53-dependent transcription by increasing the stability of p53. Moreover, lentivirus-mediated overexpression of LNX1 decreased p53 protein levels and inhibited p53-dependent transcription. LNX1 interacted with p53 and mouse double minute 2 (MDM2) and increased the ubiquitination of p53 in an MDM2-dependent manner. Finally, we demonstrated that LNX1 was required for efficient tumor growth both in cell culture and in a mouse tumor xenograft model. These results collectively indicated that LNX1 contributed to tumor growth by inhibiting p53-dependent signaling in p53 wild-type cancer cells.-Park, R., Kim, H., Jang, M., Jo, D., Park, Y.-I., Namkoong, S., Lee, J. I., Jang, I.-S., Park, J. LNX1 contributes to tumor growth by down-regulating p53 stability.

Nectandrin B-mediated activation of the AMPK pathway prevents cellular senescence in human diploid fibroblasts by reducing intracellular ROS levels.

Nectandrin B (NecB) is a bioactive lignan compound isolated from Myristica fragrans (nutmeg), which functions as an activator of AMP-activated protein kinase (AMPK). Because we recently found that treatment with NecB increased the cell viability of old human diploid fibroblasts (HDFs), the underlying molecular mechanism was investigated. NecB treatment in old HDFs reduced the activity staining of senescence-associated ß-galactosidase and the levels of senescence markers, such as the Ser15 phosphorylated p53, caveolin-1, p21waf1, p16ink4a, p27kip1, and cyclin D1. NecB treatment increased that in S phase, indicating a enhancement of cell cycle entry. Interestingly, NecB treatment ameliorated age-dependent activation of AMPK in old HDFs. Moreover, NecB reversed the age-dependent expression and/or activity changes of certain sirtuins (SIRT1-5), and cell survival/death-related proteins. The transcriptional activity of Yin-Yang 1 and the expression of downstream proteins were elevated in NecB-treated old HDFs. In addition, NecB treatment exerted a radical scavenging effect in vitro, reduced cellular ROS levels, and increased antioxidant enzymes in old HDFs. Moreover, NecB-mediated activation of the AMPK pathway reduced intracellular ROS levels. These results suggest that NecB-induced protection against cellular senescence is mediated by ROS-scavenging through activation of AMPK. NecB might be useful in ameliorating age-related diseases and extending human lifespan.

Antineuroinflammatory and Neuroprotective Effects of Gyejibokryeong-Hwan in Lipopolysaccharide-Stimulated BV2 Microglia.

Microglia, the central nervous system's innate immune cells, mediate neuroinflammation and are implicated in a variety of neuropathologies. The present study investigated the antineuroinflammatory and neuroprotective effects of Gyejibokryeong-hwan (GBH), a traditional Korean medicine, in lipopolysaccharide- (LPS-) stimulated murine BV2 microglia. BV2 cells were pretreated with GBH, fluoxetine (FXT), or amitriptyline (AMT) for 1 h and then stimulated with LPS (100 ng/mL). The expression levels of nitric oxide (NO), cytokines, and chemokines were determined by the Griess method, ELISA, or real-time PCR. Western blotting was used to measure various transcription factors and mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/Akt activity. GBH significantly reduced the levels of NO, inducible nitric oxide synthase (iNOS), cyclooxygenase- (COX-) 2, tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1ß, IL-6, macrophage inhibitory protein- (MIP-) 1α, macrophage chemoattractant protein- (MCP-) 1, and IFN-γ inducible protein- (IP-) 10, regulated upon activation normal T cell expressed sequence (RANTES) in a dose-dependent manner. Expression of nuclear factor- (NF-) κB p65 was significantly decreased and phosphorylation of extracellular signal-regulated kinase (Erk), c-Jun NH2-terminal kinase (JNK), and PI3K/Akt by GBH, but not p38 MAPK, was decreased. Furthermore, production of anti-inflammatory cytokine IL-10 was increased and Heme oxygenase-1 (HO-1) was upregulated via the nuclear factor-E2-related factor 2 (NRF2)/cAMP response element-binding protein (CREB) pathway, collectively indicating the neuroprotective effects of GBH. We concluded that GBH may suppress neuroinflammatory responses by inhibiting NF-κB activation and upregulating the neuroprotective factor, HO-1. These results suggest that GBH has potential as anti-inflammatory and neuroprotective agents against microglia-mediated neuroinflammatory disorders.

AMP-activated protein kinase regulates the expression of human telomerase reverse transcriptase.

The expression of hTERT in tumor cells contributes to oncogenic transformation by promoting immortalization. For this reason, hTERT is one of the major targets for cancer therapy, and an efficient method to downregulate hTERT expression is required for treatment of hTERT-positive cancer. In this report, we demonstrated that inhibition of AMP-activated protein kinase (AMPK) downregulates the expression of hTERT. We screened cell signaling pathways in AMPK α1 knockout cells and found that AMPKα1 is required for activity of the hTERT promoter. AMPKα1 knockout cells showed decreased expression of hTERT mRNA and protein. We also demonstrated that compound C, a reversible AMPK inhibitor, suppressed the expression of hTERT. However, AMPK activators, including AICAR and metformin, did not increase the level of hTERT protein. Finally, we showed that tumor cells stably expressing hTERT are resistant to compound C treatment. These results indicate that AMPK activity is required for tumor progression.

Modified Ginseng Extract Induces Apoptosis in HepG2 Cancer Cells by Blocking the CXCL8-Mediated Akt/Nuclear Factor-[Formula: see text]B Signaling Pathway.

The cytokine C-X-C motif chemokine ligand 8 (CXCL8) is produced in the tumor microenvironment and has an important role in cancer pathogenesis. CXCL8 activates the nuclear factor (NF)-[Formula: see text]B signaling. However, the role of NF-[Formula: see text]B inactivation in apoptosis induced by negative regulation of CXCL8 remains unclear. Here, we assessed the effects of MRGX on the transcriptional activity of NF-[Formula: see text]B and the expression of tumor necrosis factor (TNF)-[Formula: see text]-stimulated target genes in liver cancer cells. Furthermore, we found that modified regular ginseng extract (MRGX)-mediated inhibition of NF-[Formula: see text]B signaling induced apoptosis. Importantly, MRGX exerted strong activity, inhibiting TNF-[Formula: see text]-induced expression of Akt and NF-[Formula: see text]B in a concentration-dependent manner. Furthermore, MRGX inhibited the TNF-[Formula: see text]-induced expression of genes encoding CXCL8, CXCL1, inducible nitric oxide synthase and intercellular adhesion molecule 1. MRGX also dowregulated Akt activation, and there was a significant decrease in Akt activation in HepG2 cells treated with CXCL8 siRNA. Conversely, CXCL8 overexpression increased Akt activation in MRGX-treated HepG2 cells. When Akt was silenced, MRGX treatment of HepG2 cells overexpressing CXCL8 decreased nuclear translocation of NF-[Formula: see text]B, whereas Akt overexpression increased nuclear translocation of NF-[Formula: see text]B in MRGX-treated HepG2 cells. Moreover, MRGX negatively regulated the TNF-[Formula: see text]-mediated I[Formula: see text]B/NF-[Formula: see text]B pathway to promote Bax activation, resulting in caspase-3 activation and apoptosis. Taken together, these results indicated that MRGX inhibited CXCL8-mediated Akt/NF-[Formula: see text]B signaling, which upregulated Bax activation and consequently induced apoptosis in HepG2 cells.

Meridianin C inhibits the growth of YD-10B human tongue cancer cells through macropinocytosis and the down-regulation of Dickkopf-related protein-3.

Meridianin C is a marine natural product known for its anti-cancer activity. At present, the anti-tumour effects of meridianin C on oral squamous cell carcinoma are unknown. Here, we investigated the effect of meridianin C on the proliferation of four different human tongue cancer cells, YD-8, YD-10B, YD-38 and HSC-3. Among the cells tested, meridianin C most strongly reduced the growth of YD-10B cells; the most aggressive and tumorigenic of the cell lines tested. Strikingly, meridianin C induced a significant accumulation of macropinosomes in the YD-10B cells; confirmed by the microscopic and TEM analysis as well as the entry of FITC-dextran, which was sensitive to the macropinocytosis inhibitor amiloride. SEM data also revealed abundant long and thin membrane extensions that resemble lamellipodia on the surface of YD-10B cells treated with meridianin C, pointing out that meridianin C-induced macropinosomes was the result of macropinocytosis. In addition, meridianin C reduced cellular levels of Dickkopf-related protein-3 (DKK-3), a known negative regulator of macropinocytosis. A role for DKK-3 in regulating macropinocytosis in the YD-10B cells was confirmed by siRNA knockdown of endogenous DKK-3, which led to a partial accumulation of vacuoles and a reduction in cell proliferation, and by exogenous DKK-3 overexpression, which resulted in a considerable inhibition of the meridianin C-induced vacuole formation and decrease in cell survival. In summary, this is the first study reporting meridianin C has novel anti-proliferative effects via macropinocytosis in the highly tumorigenic YD-10B cell line and the effects are mediated in part through down-regulation of DKK-3.

Protein Tyrosine Phosphatases as Potential Regulators of STAT3 Signaling.

The signal transducer and activator of transcription 3 (STAT3) protein is a major transcription factor involved in many cellular processes, such as cell growth and proliferation, differentiation, migration, and cell death or cell apoptosis. It is activated in response to a variety of extracellular stimuli including cytokines and growth factors. The aberrant activation of STAT3 contributes to several human diseases, particularly cancer. Consequently, STAT3-mediated signaling continues to be extensively studied in order to identify potential targets for the development of new and more effective clinical therapeutics. STAT3 activation can be regulated, either positively or negatively, by different posttranslational mechanisms including serine or tyrosine phosphorylation/dephosphorylation, acetylation, or demethylation. One of the major mechanisms that negatively regulates STAT3 activation is dephosphorylation of the tyrosine residue essential for its activation by protein tyrosine phosphatases (PTPs). There are seven PTPs that have been shown to dephosphorylate STAT3 and, thereby, regulate STAT3 signaling: PTP receptor-type D (PTPRD), PTP receptor-type T (PTPRT), PTP receptor-type K (PTPRK), Src homology region 2 (SH-2) domain-containing phosphatase 1(SHP1), SH-2 domain-containing phosphatase 2 (SHP2), MEG2/PTP non-receptor type 9 (PTPN9), and T-cell PTP (TC-PTP)/PTP non-receptor type 2 (PTPN2). These regulators have great potential as targets for the development of more effective therapies against human disease, including cancer.

Medium chain unsaturated fatty acid ethyl esters inhibit persister formation of Escherichia coli via antitoxin HipB.

Persisters represent a small bacterial population that is dormant and that survives under antibiotic treatment without experiencing genetic adaptation. Persisters are also considered one of the major reasons for recalcitrant chronic bacterial infections. Although several mechanisms of persister formation have been proposed, it is not clear how cells enter the dormant state in the presence of antibiotics or how persister cell formation can be effectively controlled. A fatty acid compound, cis-2-decenoic acid, was reported to decrease persister formation as well as revert the dormant cells to a metabolically active state. We reasoned that some fatty acid compounds may be effective in controlling bacterial persistence because they are known to benefit host immune systems. This study investigated persister cell formation by pathogens that were exposed to nine fatty acid compounds during antibiotic treatment. We found that three medium chain unsaturated fatty acid ethyl esters (ethyl trans-2-decenoate, ethyl trans-2-octenoate, and ethyl cis-4-decenoate) decreased the level of Escherichia coli persister formation up to 110-fold when cells were exposed to ciprofloxacin or ampicillin antibiotics. RNA sequencing analysis and gene deletion persister studies elucidated that these fatty acids inhibit bacterial persistence by regulating antitoxin HipB. A similar persister cell reduction was observed for pathogenic E. coli EDL933, Pseudomonas aeruginosa PAO1, and Serratia marcescens ICU2-4 strains. This study demonstrates that fatty acid ethyl esters can be used to disrupt bacterial dormancy to combat persistent infectious diseases.

AMPK contributes to autophagosome maturation and lysosomal fusion.

AMP-activated protein kinase (AMPK) regulates autophagy initiation when intracellular ATP level decreases. However, the role of AMPK during autophagosome maturation is not fully understood. Here, we report that AMPK contributes to efficient autophagosome maturation and lysosomal fusion. Using CRISPR-Cas9 gene editing, we generated AMPK α1 knockout HEK293T cell lines, in which starvation-induced autophagy is impaired. Compound C, an AMPK-independent autophagy inducer, and trehalose, an mTOR-independent autophagy inducer were used to examine the role of AMPK in autophagosome maturation and lysosomal fusion. While the treatment of control cells with either compound C or trehalose induces activation of autophagosomes as well as autolysosomes, the treatment of AMPK α1 knockout cells with compound C or trehalose induces mainly activation of autophagosomes, but not autolysosomes. We demonstrate that this effect is due to interference with the fusion of autophagosomes with lysosomes in AMPK α1 knockout cells. The transient expression of AMPK α1 can rescue autophagosome maturation. These results indicate that AMPK α1 is required for efficient autophagosome maturation and lysosomal fusion.

Antidepressant-Like Effects of Gyejibokryeong-hwan in a Mouse Model of Reserpine-Induced Depression.

Treatment with the antihypertensive agent reserpine depletes monoamine levels, resulting in depression. In the present study, we evaluated the antidepressant effects of Gyejibokryeong-hwan (GBH), a traditional Korean medicine, in a mouse model of reserpine-induced depression. Mice were treated with reserpine (0.5 mg·kg-1, i.p.) or phosphate-buffered saline (PBS, i.p., normal) once daily for 10 days. GBH (50, 100, 300, and 500 mg·kg-1), PBS (normal, control), fluoxetine (FXT, 20 mg·kg-1), or amitriptyline (AMT, 30 mg·kg-1) was administered orally 1 h prior to reserpine treatment. Mouse behavior was examined in the forced swim test (FST), tail suspension test (TST), and open-field test (OFT) following completion of the treatment protocol. Administration of GBH reduced immobility time in the FST and TST and significantly increased the total distance traveled in the OFT. Plasma serotonin levels were significantly lower in control mice than in normal mice, although these decreases were significantly attenuated to a similar extent by treatment with GBH, FXT, or AMT. Reserpine-induced increases in plasma corticosterone were also attenuated by GBH treatment. Moreover, GBH attenuated reserpine-induced increases in interleukin- (IL-) 1ß, IL-6, and tumor necrosis factor- (TNF-) α mRNA expression in the hippocampus. In addition, GBH mice exhibited increased levels of brain-derived neurotrophic factor (BDNF) and a higher ratio of phosphorylated cAMP response element-binding protein (p-CREB) to CREB (p-CREB/CREB) in the hippocampus. Our results indicated that GBH can ameliorate depressive-like behaviors, affect the concentration of mood-related hormones, and help to regulate immune/endocrine dysfunction in mice with reserpine-induced depression, likely via activation of the BDNF-CREB pathway. Taken together, these findings indicate that GBH may be effective in treating patients with depression.

Epidermal-specific deletion of TC-PTP promotes UVB-induced epidermal cell survival through the regulation of Flk-1/JNK signaling.

UVB exposure can contribute to the development of skin cancer by modulating protein tyrosine kinase (PTK) signaling. It has been suggested that UVB radiation increases the ligand-dependent activation of PTKs and induces PTP inactivation. Our recent studies have shown that T-cell protein tyrosine phosphatase (TC-PTP) attenuates skin carcinogenesis induced by chemical regimens, which indicates its critical role in the prevention of skin cancer. In the current work, we report that TC-PTP increases keratinocyte susceptibility to UVB-induced apoptosis via the downregulation of Flk-1/JNK signaling. We showed that loss of TC-PTP led to resistance to UVB-induced apoptosis in vivo epidermis. We established immortalized primary keratinocytes (IPKs) from epidermal-specific TC-PTP-deficient (K14Cre.Ptpn2fl/fl) mice. Immortalized TC-PTP-deficient keratinocytes (TC-PTP/KO IPKs) showed increased cell survival against UVB-induced apoptosis which was concomitant with a UVB-mediated increase in Flk-1 phosphorylation, especially on tyrosine residue 1173. Inhibition of Flk-1 by either its specific inhibitors or siRNA in TC-PTP/KO IPKs reversed this effect and significantly increased cell death after UVB irradiation in comparison with untreated TC-PTP/KO IPKs. Immunoprecipitation analysis using the TC-PTP substrate-trapping mutant TCPTP-D182A indicated that TC-PTP directly interacts with Flk-1 to dephosphorylate it and their interaction was stimulated by UVB. Following UVB-mediated Flk-1 activation, the level of JNK phosphorylation was also significantly increased in TC-PTP/KO IPKs compared to control IPKs. Similar to our results with Flk-1, treatment of TC-PTP/KO IPKs with the JNK inhibitor SP600125 significantly increased apoptosis after UVB irradiation, confirming that the effect of TC-PTP on UVB-mediated apoptosis is regulated by Flk-1/JNK signaling. Western blot analysis showed that both phosphorylated Flk-1 and phosphorylated JNK were significantly increased in the epidermis of TC-PTP-deficient mice compared to control mice following UVB. Our results suggest that TC-PTP plays a protective role against UVB-induced keratinocyte cell damage by promoting apoptosis via negative regulation of Flk-1/JNK survival signaling.