Combination of matrine and tacrolimus alleviates acute rejection in murine heart transplantation by inhibiting DCs maturation through ROS/ERK/NF-κB pathway

Matrine, an alkaloid derived from traditional Chinese herbs, has been confirmed to regulate immunity and exert anti-inflammatory effects. Matrine injection has been widely used in clinic therapy for anti-tumor and anti-inflammatory diseases. Heart transplantation(HT) is the only solution for the end-stage heart failure, but it is restricted by the cardiac allograft rejection. One of the important pathophysiological processes of post-transplantation rejection is inflammatory cell infiltration. Matrine has been shown to exert a positive protective effect against oxidative stress injury and inflammation, which likely benefits allograft survival. However, it remains unclear whether matrine inhibits alloimmunity or allograft rejection. In this study, we established the heart transplantation model in mouse and extracted bone marrow-derived dendritic cells (BMDCs) to explore the function and mechanism of matrine in heart transplantation. Moreover, combination treatment with matrine and tacrolimus(FK506) had a synergistic effect in preventing acute rejection of heart transplants. Here we found that matrine can prolong the survival of post-transplant and inhibit inflammatory cell infiltration in transplanted hearts of mice. At the same time, matrine increased Treg ratio and decreased CD4+/CD8 + ratio in mice. More importantly, matrine inhibited DCs maturation in mice and reduced oxidative damage and apoptosis in allograft hearts. Furthermore, matrine also downregulated NF-κB pathway and upregulated ERK1/2 signaling pathway. Overall, our study reveals a novel immunosuppressive agent that has the potential to reduce the side effects of existing immunosuppressive agents when used in combination with them.

7,8-Dihydroxiflavone Protects Adult Rat Axotomized Retinal Ganglion Cells through MAPK/ERK and PI3K/AKT Activation

We analyze the 7,8-dihydroxyflavone (DHF)/TrkB signaling activation of two main intracellular pathways, mitogen-activated protein kinase (MAPK)/ERK and phosphatidylinositol 3 kinase (PI3K)/AKT, in the neuroprotection of axotomized retinal ganglion cells (RGCs). Methods: Adult albino Sprague-Dawley rats received left intraorbital optic nerve transection (IONT) and were divided in two groups. One group received daily intraperitoneal DHF (5 mg/kg) and another vehicle (1%DMSO in 0.9%NaCl) from one day before IONT until processing. Additional intact rats were employed as control (n = 4). At 1, 3 or 7 days (d) after IONT, phosphorylated (p)AKT, p-MAPK, and non-phosphorylated AKT and MAPK expression levels were analyzed in the retina by Western blotting (n = 4/group). Radial sections were also immunodetected for the above-mentioned proteins, and for Brn3a and vimentin to identify RGCs and Müller cells (MCs), respectively (n = 3/group). Results: IONT induced increased levels of p-MAPK and MAPK at 3d in DHF- or vehicle-treated retinas and at 7d in DHF-treated retinas. IONT induced a fast decrease in AKT in retinas treated with DHF or vehicle, with higher levels of phosphorylation in DHF-treated retinas at 7d. In intact retinas and vehicle-treated groups, no p-MAPK or MAPK expression in RGCs was observed. In DHF- treated retinas p-MAPK and MAPK were expressed in the ganglion cell layer and in the RGC nuclei 3 and 7d after IONT. AKT was observed in intact and axotomized RGCs, but the signal intensity of p-AKT was stronger in DHF-treated retinas. Finally, MCs expressed higher quantities of both MAPK and AKT at 3d in both DHF- and vehicle-treated retinas, and at 7d the phosphorylation of p-MAPK was higher in DHF-treated groups. Conclusions: Phosphorylation and increased levels of AKT and MAPK through MCs and RGCs in retinas after DHF-treatment may be responsible for the increased and long-lasting RGC protection afforded by DHF after IONT.

Urantide prevents CCl4‑induced acute liver injury in rats by regulating the MAPK signalling pathway

A number of drugs and other triggers can cause acute liver injury (ALI) in clinical practice. Therefore, identifying a safe drug for the prevention of liver injury is important. The aim of the present study was to investigate the potential preventive effect and regulatory mechanism of urantide on carbon tetrachloride (CCl4)‑induced ALI by investigating the expression of components of the MAPK signalling pathway and the urotensin II (UII)/urotensin receptor (UT) system. Liver oedema and severe fatty degeneration of the cytoplasm were observed in ALI model rats, and the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were found to be significantly increased. Compared with those in the ALI model group, ALT and AST levels and the liver index did not significantly increase in each group given the preventive administration of urantide, and the liver tissue morphology was correspondingly protected. Moreover, the gene and protein expression levels of UII, G protein‑coupled receptor (GPR14) and the oxidative stress‑sensitive cytokines, α‑smooth muscle actin and osteopontin were decreased, indicating that the protein translation process was effectively maintained. However, the expression levels of MAPK signalling pathway‑related proteins and genes were decreased. It was found that urantide could effectively block the MAPK signalling pathway by antagonizing the UII/UT system, thus protecting the livers of ALI model rats. Therefore, it was suggested that ALI may be associated with the MAPK signalling pathway, and effective inhibition of the MAPK signalling pathway may be critical in protecting the liver.

Ferulic Acid Metabolites Attenuate LPS-Induced Inflammatory Response in Enterocyte-like Cells

Ferulic acid (FA) is a polyphenol pertaining to the class of hydroxycinnamic acids present in numerous foods of a plant origin. Its dietary consumption leads to the formation of several phase I and II metabolites in vivo, which represent the largest amount of ferulates in the circulation and in the intestine in comparison with FA itself. In this work, we evaluated their efficacy against the proinflammatory effects induced by lipopolysaccharide (LPS) in intestinal Caco-2 cell monolayers, as well as the mechanisms underlying their protective action. LPS-induced overexpression of proinflammatory enzymes such as inducible nitric oxide synthase (iNOS) and the consequent hyperproduction of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) were limited by physiological relevant concentrations (1 µM) of FA, its derivatives isoferulic acid (IFA) and dihydroferulic acid (DHFA), and their glucuronidated and sulfated metabolites, which acted upstream by limiting the activation of MAPK p38 and ERK and of Akt kinase, thus decreasing the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB) translocation into the nucleus. Furthermore, the compounds were found to promote the expression of Nrf2, which may have contributed to the downregulation of NF-ĸB activity. The overall data show that phase I/II metabolites retain the efficacy of their dietary free form in contrasting inflammatory response.

Yersinia pseudotuberculosis YopJ Limits Macrophage Response by Downregulating COX-2-Mediated Biosynthesis of PGE2 in a MAPK/ERK-Dependent Manner

Prostaglandin E2 (PGE2) is an essential immunomodulatory lipid released by cells in response to infection with many bacteria, yet its function in macrophage-mediated bacterial clearance is poorly understood. Yersinia overall inhibits the inflammatory circuit, but its effect on PGE2 production is unknown. We hypothesized that one of the Yersinia effector proteins is responsible for the inhibition of PGE2 biosynthesis. We identified that yopB-deficient Y. enterocolitica and Y. pseudotuberculosis deficient in the secretion of virulence proteins via a type 3 secretion system (T3SS) failed to inhibit PGE2 biosynthesis in macrophages. Consistently, COX-2-mediated PGE2 biosynthesis is upregulated in cells treated with heat-killed or T3SS-deficient Y. pseudotuberculosis but diminished in the presence of a MAPK/ERK inhibitor. Mutants expressing catalytically inactive YopJ induce similar levels of PGE2 as heat-killed or ΔyopB Y. pseudotuberculosis, reversed by YopJ complementation. Shotgun proteomics discovered host pathways regulated in a YopJ-mediated manner, including pathways regulating PGE2 synthesis and oxidative phosphorylation. Consequently, this study identified that YopJ-mediated inhibition of MAPK signal transduction serves as a mechanism targeting PGE2, an alternative means of inflammasome inhibition by Yersinia. Finally, we showed that EP4 signaling supports macrophage function in clearing intracellular bacteria. In summary, our unique contribution was to determine a bacterial virulence factor that targets COX-2 transcription, thereby enhancing the intracellular survival of yersiniae. Future studies should investigate whether PGE2 or its stable synthetic derivatives could serve as a potential therapeutic molecule to improve the outcomes of specific bacterial infections. Since other pathogens encode YopJ homologs, this mechanism is expected to be present in other infections. IMPORTANCE PGE2 is a critical immunomodulatory lipid, but its role in bacterial infection and pathogen clearance is poorly understood. We previously demonstrated that PGE2 leads to macrophage polarization toward the M1 phenotype and stimulates inflammasome activation in infected macrophages. Finally, we also discovered that PGE2 improved the clearance of Y. enterocolitica. The fact that Y. enterocolitica hampers PGE2 secretion in a type 3 secretion system (T3SS)-dependent manner and because PGE2 appears to assist macrophage in the clearance of this bacterium indicates that targeting of the eicosanoid pathway by Yersinia might be an adaption used to counteract host defenses. Our study identified a mechanism used by Yersinia that obstructs PGE2 biosynthesis in human macrophages. We showed that Y. pseudotuberculosis interferes with PGE2 biosynthesis by using one of its T3SS effectors, YopJ. Specifically, YopJ targets the host COX-2 enzyme responsible for PGE2 biosynthesis, which happens in a MAPK/ER-dependent manner. Moreover, in a shotgun proteomics study, we also discovered other pathways that catalytically active YopJ targets in the infected macrophages. YopJ was revealed to play a role in limiting host LPS responses, including repression of EGR1 and JUN proteins, which control transcriptional activation of proinflammatory cytokine production such as interleukin-1β. Since YopJ has homologs in other bacterial species, there are likely other pathogens that target and inhibit PGE2 biosynthesis. In summary, our study's unique contribution was to determine a bacterial virulence factor that targets COX-2 transcription. Future studies should investigate whether PGE2 or its stable synthetic derivatives could serve as a potential therapeutic target.

Effects of Ulinastatin on Proliferation and Apoptosis of Breast Cancer Cells by Inhibiting the ERK Signaling Pathway

PURPOSE

To explore the effects of ulinastatin on the proliferation and apoptosis of breast cancer cells and the relevant mechanism of action.

METHODS

Breast cancer cells (MCF-7) were cultured and randomly divided into three groups, namely, control group, ulinastatin group, and ulinastatin+extracellular-regulated protein kinase (ERK) inhibitor group. Then, the Cell Counting Kit-8 (CCK-8) assay was carried out to detect the effect of ulinastatin on the viability of breast cancer cells. The effects of ulinastatin on the proliferation and apoptosis of breast cancer cells were determined via EdU staining and Hoechst 33258 staining assays, respectively. The messenger ribonucleic acid (mRNA) and protein expression levels of ERK and forkhead box O3 (FOXO3) in breast cancer cells were measured through reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.

RESULTS

In comparison with the control group, the ulinastatin group displayed decreased viability of breast cancer cells, a decreased positive rate of 5-ethynyl-2'-deoxyuridine (EdU) staining, an increased positive rate of Hoechst 33258 staining, and reduced mRNA and protein levels of ERK and FOXO3 in breast cancer cells. Compared with those in the ulinastatin group, the viability of breast cancer cells was lowered, the positive rate of EdU staining was reduced, the positive rate of Hoechst 33258 staining was raised, and the mRNA and protein levels of ERK and FOXO3 in breast cancer cells clearly declined in the ulinastatin+ERK inhibitor group.

CONCLUSION

Ulinastatin inhibits the proliferation and promotes the apoptosis of breast cancer cells. The possible mechanism of action is associated with the suppression of the ERK signaling pathway.

Planarian stem cells sense the identity of the missing pharynx to launch its targeted regeneration

In order to regenerate tissues successfully, stem cells must detect injuries and restore missing cell types through largely unknown mechanisms. Planarian flatworms have an extensive stem cell population responsible for regenerating any organ after amputation. Here, we compare planarian stem cell responses to different injuries by either amputation of a single organ, the pharynx, or removal of tissues from other organs by decapitation. We find that planarian stem cells adopt distinct behaviors depending on what tissue is missing to target progenitor and tissue production towards missing tissues. Loss of non-pharyngeal tissues only increases non-pharyngeal progenitors, while pharynx removal selectively triggers division and expansion of pharynx progenitors. By pharmacologically inhibiting either mitosis or activation of the MAP kinase ERK, we identify a narrow window of time during which stem cell division and ERK signaling produces pharynx progenitors necessary for regeneration. These results indicate that planarian stem cells can tailor their output to match the regenerative needs of the animal.

Qizhen capsule inhibits colorectal cancer by inducing NAG-1/GDF15 expression that mediated via MAPK/ERK activation

ETHNOPHARMACOLOGICAL RELEVANCE

Qizhen capsule (QZC) is a traditional Chinese medicine (TCM) preparation that has been widely used in clinical practice and exerts promising therapeutic effects against breast, lung, and gastric cancers. However, studies have not reported whether QZC inhibits colorectal cancer (CRC) development and progression. Meanwhile, the underlying molecular mechanisms of its anticancer activity have not been studied.

AIM OF THE STUDY

To investigate the anticancer effects of QZC on CRC and the possible underlying molecular mechanisms of QZC in vitro and in vivo.

MATERIALS AND METHODS

The MTT assay and flow cytometry were used to determine the viability and apoptosis of HCT116 and HT-29 cancer cells. A xenograft nude mouse model was used to study the antitumor effects of QZC in vivo. Western blotting was performed to determine the expression of key proteins responsible for the molecular mechanisms elicited by QZC. Immunofluorescence staining was performed to detect the expression of nonsteroidal anti-inflammatory drug (NSAID)-activated gene-1 or growth differentiation factor-15 (NAG-1/GDF15). Small interfering RNAs (siRNAs) were used to silence NAG-1/GDF15 in cells.

RESULTS

In this study, QZC significantly reduced the viability of HCT116 and HT-29 cells and induced apoptosis in dose- and time-dependent manners, but displayed much less toxicity toward normal cells. QZC-induced apoptosis in HCT116 cells was accompanied by the deregulation of the expression of the Bcl-2, Bax, PARP, caspase-3, and caspase-9 proteins. Furthermore, QZC induced NAG-1/GDF15 expression in HCT116 cells, while silencing of NAG-1/GDF15 attenuated QZC-induced apoptosis and cell death. Next, QZC increased the phosphorylation of mTOR, AMPK, p38, and MAPK/ERK in HCT116 cells. We then demonstrated that QZC-induced apoptosis and NAG-1/GDF15 upregulation were mediated by MAPK/ERK activation. Moreover, QZC significantly inhibited HCT116 xenograft tumor growth in nude mice, which was accompanied by NAG/GDF15 upregulation and MAPK/ERK activation. QZC also prevented 5-FU-induced weight loss or cachexia in tumor-bearing mice. The expression of Ki67 and PCNA was suppressed, while cleaved caspase-3 level and TUNEL staining were increased in the tumor sections from QZC-treated mice compared to the control.

CONCLUSION

QZC is a novel anticancer agent for CRC that targets NAG-1/GDF15 via the MAPK/ERK signaling pathway.

Suppression of synuclein gamma inhibits the movability of endometrial carcinoma cells by PI3K/AKT/ERK signaling pathway

BACKGROUND

Although overexpression of synuclein gamma (SNCG) has been reported in several cancers, few studies have been performed onSNCG in endometrial carcinomas.

OBJECTIVE

This study aimed to investigate the role of SNCG in the progression of endometrial carcinoma.

METHODS

The expression pattern and function ofSNCG gene were analyzed using the Gene Expression Omnibus (GEO) and Gene Set Enrichment Analysis (GSEA) datasets. Two vector types, containing either SNCG or negative control shRNAs, were used to evaluate cell proliferation, apoptosis, and metastasis using Cell Counting Kit 8, colony formation, flow cytometry, wound-healing, transwell, and invasion assays. The relative protein levels of N-cadherin, E-cadherin, vimentin, p-PI3K, PI3K, p-AKT, AKT, p-ERK, and ERK were determined by western bloting.

RESULTS

Our results revealed thatSNCG mRNA expression and SNCG protein levels in shRNA-treated SPEC2 cells were lower than in the negative control cells. Furthermore, cell proliferation, migration, and invasion were significantly inhibited in SNCG shRNA-treated cells, but apoptosis was increased. The results of western blot analysis indicated that SNCG silencing reduced the protein levels of N-cadherin, vimentin, p-PI3K, p-AKT, and p-ERK, but not those of total PI3K, AKT, and ERK.

CONCLUSIONS

Therefore, shRNA-mediated suppression of SNCG inhibited SPEC2 cell proliferation, migration, and invasion, and promoted SPEC2 cell apoptosis, which was presumably accomplished via regulation of the PI3K/AKT/ERK signaling pathway.

Neutrophil extracellular DNA traps promote pancreatic cancer cells migration and invasion by activating EGFR/ERK pathway

Neutrophil extracellular DNA traps (NETs) are newly discovered forms of activated neutrophils. Increasing researches have shown that NETs play important roles in cancer progression. Our previous study has proved that tumour-infiltrating NETs could predict postsurgical survival in patients with pancreatic ductal adenocarcinoma (PDAC). However, the roles of NETs on the progression of pancreatic cancer are unknown. Here, we investigated the effects of NETs on pancreatic cancer cells. Results showed that both PDAC patients' and normal individuals' neutrophils-derived NETs could promote migration and invasion of pancreatic cancer cells with epithelial-mesenchymal transition. Further, study confirmed that EGFR/ERK pathway played an important role in this progression. The addition of neutralizing antibodies for IL-1β could effectively block the activation of EGFR/ERK companied with reduction of EMT, migration and invasion. Taken together, NETs facilitated EMT, migration and invasion via IL-1β/EGFR/ERK pathway in pancreatic cancer cells. Our study suggests that NETs may provide promising therapeutic targets for pancreatic cancer.

IRS4 promotes the progression of non-small cell lung cancer and confers resistance to EGFR-TKI through the activation of PI3K/Akt and Ras-MAPK pathways

IRS4 is a member of the insulin receptor substrate (IRS) protein family. It acts as a cytoplasmic adaptor protein, integrating and transmitting signals from receptor protein tyrosine kinases to the intracellular environment. IRS4 can induce mammary tumorigenesis and is usually overexpressed in non-small cell lung cancer (NSCLC). However, little is known about the role of IRS4 in the development and progression of lung cancer. In this study, we show that IRS4 knockout suppresses the proliferation, colony formation, migration, and invasion of A549 lung cancer cells, as well as tumor growth in a nude mouse xenograft model. In contrast, stable expression of IRS4 showed the opposite effects. As expected, IRS4 was found to activate the PI3K/Akt and Ras-MAPK pathways, and we also showed that IRS4 depletion significantly enhanced the sensitivity of EGFR tyrosine kinase inhibitor (EGFR-TKI)-resistant cells to gefitinib. Taken together, these results show that IRS4 promotes NSCLC progression and may represent a potential therapeutic target for EGFR-TKI-resistant NSCLC.

LncRNA SOX2-OT regulates AKT/ERK and SOX2/GLI-1 expression, hinders therapy, and worsens clinical prognosis in malignant lung diseases

The involvement of LncRNA SOX2-overlapping transcript (SOX2-OT), SOX2, and GLI-1 transcription factors in cancer has been well documented. Nonetheless, it is still unknown whether co-expressed SOX2-OT/SOX2 or SOX2-OT/SOX2/GLI-1 axes are epigenetically/transcriptionally involved in terms of resistance to oncology therapy and in poorer clinical outcomes for patients with lung cancer. We evaluated the role of SOX2-OT/SOX2 and SOX2-OT/SOX2/GLI-1 axes using RT-qPCR, western blot, immunofluorescence analyses, gene silencing, cellular cytotoxic, and ChIP-qPCR assays on human cell lines, solid lung malignant tumors, and normal lung tissue. We detected that the SOX2-OT/SOX2/GLI-1 axis promotes resistance to tyrosine kinase inhibitor (TKI)-erlotinib and cisplatin-based therapy. Evidence from this study show that SOX2-OT modulates the expression/activation of EGFR-pathway members AKT/ERK. Further, both SOX2-OT and GLI-1 genes are epigenetically regulated at their promoter sequences, in an LncRNA SOX2-OT-dependent manner, mainly through modifying the enrichment of the activation histone mark H3K4me3/H3K27Ac, versus the repressive histone mark H3K9me3/H3K27me3. In addition, we identified that inhibition of SOX2-OT and reduced expression of SOX2/GLI-1 sensitizes lung cancer cells to EGFR/TKI-erlotinib or cisplatin-based treatment. Finally, we show that high co-expression of SOX2-OT/SOX2 transcripts and SOX2/GLI-1 proteins appears to correlate with a poor clinical prognosis and lung malignant phenotype. Collectively, these results present evidence that LncRNA SOX2-OT modulates an orchestrated resistance mechanism, promoting poor prognosis and human lung malignancy through genetic, epigenetic, and post-translational mechanisms.

Benzo(a)pyrene induces MUC5AC expression through the AhR/mitochondrial ROS/ERK pathway in airway epithelial cells

OBJECTIVES

Benzo(a)pyrene (BaP) is a ubiquitous air pollutants, and BaP exposure leads to a risk of respiratory diseases. The oversecretion of airway mucus and high expression of mucin 5AC (MUC5AC) are associated with common respiratory disorders caused by air pollution. We aimed to investigate the effect of BaP on MUC5AC expression, especially the mechanisms by which BaP induces MUC5AC gene expression.

METHODS

The human airway epithelial cell NCI-H292 was used to test the effects of BaP on the expression of MUC5AC in vitro. MUC5AC mRNA and protein expression were assessed with real-time quantitative PCR, immunochemistry, and western blotting. A luciferase assay was conducted to detect the activity of the promoter. The total cellular ROS and mitochondrial ROS were measured by corresponding probes. Small-interfering RNAs were used for gene silencing. AhR-overexpressing cell lines were constructed by transfection with AhR overexpression lentivirus.

RESULTS

We found that BaP stimulation upregulated the MUC5AC mRNA and protein levels and activated the ERK pathway. Suppressing ERK with U0126 (an ERK inhibitor) or knocking down ERK with siRNA decreased BaP-induced MUC5AC expression. The luciferase activity transfected with the MUC5AC promoter and cAMP-response element (CRE) was increased after BaP treatment, whereas CREB siRNA suppressed the BaP-induced overexpression of MUC5AC. In addition, BaP increased mitochondrial ROS production, and Mito-TEMP, a mitochondrial ROS inhibitor, inhibited BaP-induced MUC5AC expression and ERK activation. BaP increased the mRNA levels of CYP1A1 and CYP1B1, while Alizarin, a CYP1s inhibitor, suppressed the effects of BaP, including the MUC5AC overexpression, ERK activation and mitochondrial ROS generation. BaP induced the translocation of aryl hydrocarbon receptor (AhR) from the cytoplasm to the nucleus. SiRNA-mediated knockdown or chemical inhibition of AhR decreased the BaP-induced expression of MUC5AC, while the overexpression of AhR significantly enhanced the BaP-induced expression of MUC5AC. ITE, an endogenous AhR ligand, also upregulated the mRNA and protein expression of MUC5AC. Furthermore, resveratrol treatment inhibited the BaP-induced MUC5AC overexpression, AhR translocation, mitochondrial ROS production and ERK pathway activation.

CONCLUSION

Here, we highlighted the crucial role of AhR/mitochondrial ROS/ERK pathway activation in BaP-induced MUC5AC overexpression and identified resveratrol as a promising drug to reduce BaP-induced MUC5AC overexpression.

Probiotic Activity of Staphylococcus epidermidis Induces Collagen Type I Production through FFaR2/p-ERK Signaling

Collagen type I is a key structural component of dermis tissue and is produced by fibroblasts and the extracellular matrix. The skin aging process, which is caused by intrinsic or extrinsic factors, such as natural aging or free radical exposure, greatly reduces collagen expression, thereby leading to obstructed skin elasticity. We investigated the effective fermentation of Cetearyl isononanoate (CIN), a polyethylene glycol (PEG) analog, as a carbon source with the skin probiotic bacterium Staphylococcus epidermidis (S.epidermidis) or butyrate, as their fermentation metabolites could noticeably restore collagen expression through phosphorylated extracellular signal regulated kinase (p-ERK) activation in mouse fibroblast cells and skin. Both the in vitro and in vivo knockdown of short-chain fatty acid (SCFA) or free fatty acid receptor 2 (FFaR2) considerably blocked the probiotic effect of S. epidermidis on p-ERK-induced collagen type I induction. These results demonstrate that butyric acid (BA) in the metabolites of fermenting skin probiotic bacteria mediates FFaR2 to induce the synthesis of collagen through p-ERK activation. We hereby imply that metabolites from the probiotic S. epidermidis fermentation of CIN as a potential carbon source could restore impaired collagen in the dermal extracellular matrix (ECM), providing integrity and elasticity to skin.

STK39 is a novel kinase contributing to the progression of hepatocellular carcinoma by the PLK1/ERK signaling pathway

Rationale: Protein kinases are critical therapeutic targets for curing hepatocellular carcinoma (HCC). As a serine/threonine kinase, the potential roles of serine/threonine kinase 39 (STK39) in HCC remain to be explored. Methods: The expression of STK39 was examined by RT-qPCR, western blotting and immunohistochemistry. Cell proliferation and apoptosis were detected by CCK8 and TUNEL kit. Cell migration and invasion assays were performed using a transwell system with or without Matrigel. RNA-seq, mass spectrometry and luciferase reporter assays were used to identify STK39 binding proteins. Results: Here, we firstly report that STK39 was highly overexpressed in clinical HCC tissues compared with adjacent tissues, high expression of STK39 was induced by transcription factor SP1 and correlated with poor patient survival. Gain and loss of function assays revealed that overexpression of STK39 promoted HCC cell proliferation, migration and invasion. In contrast, the depletion of STK39 attenuated the growth and metastasis of HCC cells. Moreover, knockdown of STK39 induced the HCC cell cycle arrested in the G2/M phase and promoted apoptosis. In mechanistic studies, RNA-seq revealed that STK39 positively regulated the ERK signaling pathway. Mass spectrometry identified that STK39 bound to PLK1 and STK39 promoted HCC progression and activated ERK signaling pathway dependent on PLK1. Conclusions: Thus, our study uncovers a novel role of STK39/PLK1/ERK signaling axis in the progress of HCC and suggests STK39 as an indicator for prognosis and a potential drug target of HCC.

Neuronal calcitonin gene-related peptide promotes prostate tumor growth in the bone microenvironment

Advanced stage of prostate cancer cells preferentially metastasizes to varying bones of prostate cancer patients, resulting in incurable disease with poor prognosis and limited therapeutical treatment options. Calcitonin gene-related peptide (CGRP), a neuropeptide produced by prostate gland, is known to play a pivotal role in facilitating tumor growth and metastasis of numerous human cancers. In this study, we aim to investigate the clinical relevance of CGRP in prostate cancer patients and the effects of CGRP and CGRP antagonists on prostate tumor growth in the mouse model. The prostate tumor-bearing mice were received either CGRP or CGRP antagonist treatment, and the tumor growth was monitored by quantification of luminescence intensities. We found that the CGRP⁺ nerve fiber density and serum CGRP levels were substantially upregulated in the bone or serum specimens from advanced prostate cancer patients as well as in prostate tumor-bearing mice. Administration of CGRP promoted, whereas treatment of CGRP antagonists inhibited prostate tumor growth in the femurs of mice. In addition, CGRP treatment activated extracellular signal-regulated kinases (ERKs)/ Signal transducer and activator of transcription 3 (STAT3) signaling in prostate cancer cells. Targeting CGRP may serve as a potential therapeutic strategy for advanced prostate cancer patients.

Interaction network of proteins associated with unfavorable prognosis in acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignant disorder of hematopoietic stem and progenitor cells, characterized by accumulation of immature blasts in the bone marrow and peripheral blood of affected patients. Standard induction therapy leads to complete remission in approximately 50% to 75% of patients. In spite of favorable primary response rates, only 20% to 30% of patients enjoy long-term disease free survival. Identifying proteins involved in prognosis is important for proposing biomarkers that can aid in the clinical management of the disease. The aim of this study was to construct a protein-protein interaction (PPI) network based on serum proteins associated with unfavorable prognosis of AML, and analyze the biological pathways underlying molecular complexes in the network. We identified 16 candidate serum proteins associated with unfavorable prognosis (in terms of poor response to treatment, poor overall survival, short complete remission, and relapse) in AML via a search in the literature: IL2RA, FTL, HSP90AA1, D2HGDH, PLAU, COL18A1, FGF19, SPP1, FGA, PF4, NME1, TNF, ANGPT2, B2M, CD274, LGALS3. The PPI network was constructed with Cytoscape using association networks from String and BioGRID, and Gene Ontology enrichment analysis using the ClueGo pluggin was performed. The central protein in the network was found to be PTPN11 which is involved in modulating the RAS-ERK, PI3K-AKT and JAK-STAT pathways, as well as in hematopoiesis, and in the regulation of apoptotic genes. Therefore, a dysregulation of this protein and/or of the proteins connected to it in the network leads to the defective activation of these signaling pathways and to a reduction in apoptosis. Together, this could cause an increase in the frequency of leukemic cells and a resistance to apoptosis in response to treatment.

Transforming growth factor beta signaling and decidual integrity in mice†

Transforming growth factor beta (TGFβ) signaling regulates multifaceted reproductive processes. It has been shown that the type 1 receptor of TGFβ (TGFBR1) is indispensable for female reproductive tract development, implantation, placental development, and fertility. However, the role of TGFβ signaling in decidual development and function remains poorly defined. Our objective is to determine the impact of uterine-specific deletion of Tgfbr1 on decidual integrity, with a focus on the cellular and molecular properties of the decidua during development. Our results show that the developmental dynamics of the decidua is altered in TGFBR1 conditionally depleted uteri from embryonic day (E) 5.5 to E8.5, substantiated by downregulation of genes associated with inflammatory responses and uterine natural killer cell abundance, reduced presence of nondecidualized fibroblasts in the antimesometrial region, and altered decidual cell development. Notably, conditional ablation of TGFBR1 results in the formation of decidua containing more abundant alpha smooth muscle actin (ACTA2)-positive cells at the peripheral region of the antimesometrial side versus controls at E6.5-E8.5. This finding is corroborated by upregulation of a subset of smooth muscle marker genes in Tgfbr1 conditionally deleted decidua at E6.5 and E8.5. Moreover, increased cell proliferation and enhanced decidual ERK1/2 signaling were found in Tgfbr1 conditional knockout mice upon decidual regression. In summary, conditional ablation of TGFBR1 in the uterus profoundly impacts the cellular and molecular properties of the decidua. Our results suggest that TGFBR1 in uterine epithelial and stromal compartments is important for the integrity of the decidua, a transient but crucial structure that supports embryo development.

White Adipose Tissue Expansion in Multiple Symmetric Lipomatosis Is Associated with Upregulation of CK2, AKT and ERK1/2

Multiple symmetric lipomatosis (MSL) is a rare disorder characterized by overgrowing lipomatous tissue (LT) in the subcutaneous adipose tissue (SAT). What LT is and how it expands are not completely understood; previous data suggested that it could derive from brown AT precursors. In six MSL type I patients, we compared LT morphology by histological and immunohistochemistry (IHC) analysis, gene expression, by qPCR, kinase activity, by Western Blot and in vitro assay to paired-control SAT using AT from patients with pheochromocytoma as a human browning reference. In the stromal vascular fraction (SVF), we quantified adipose stem cells (ASCs) by flow cytometry, the proliferation rate, white and beige adipogenic potential and clonogenicity and adipogenicity by a limiting dilution assay. LT displayed white AT morphology and expression pattern and did not show increased levels of the brown-specific marker UCP1. In LT, we evidenced AKT, CK2 and ERK1/2 hyperactivation. LT-SVF contained increased ASCs, proliferated faster, sprouted clones and differentiated into adipocytes better than the control, displaying enhanced white adipogenic potential but not increased browning compared to SAT. In conclusion, LT is a white AT depot expanding by hyperplasia through increased stemness and enhanced white adipogenesis upregulating AKT, CK2 and ERK1/2, which could represent new targets to counteract MSL.

Disulfides from the Brown Alga Dictyopteris membranacea Suppress M1 Macrophage Activation by Inducing AKT and Suppressing MAPK/ERK Signaling Pathways

Inflammation is part of the organism's response to deleterious stimuli, such as pathogens, damaged cells, or irritants. Macrophages orchestrate the inflammatory response obtaining different activation phenotypes broadly defined as M1 (pro-inflammatory) or M2 (homeostatic) phenotypes, which contribute to pathogen elimination or disease pathogenesis. The type and magnitude of the response of macrophages are shaped by endogenous and exogenous factors and can be affected by nutrients or therapeutic agents. Multiple studies have shown that natural products possess immunomodulatory properties and that marine algae contain products with such action. We have previously shown that disulfides isolated from Dictyopteris membranacea suppress nitric oxide (NO) production from activated macrophages, suggesting potential anti-inflammatory actions. In this study, we investigated the anti-inflammatory mechanism of action of bis(5-methylthio-3-oxo-undecyl) disulfide (1), 5-methylthio-1-(3-oxo-undecyl) disulfanylundecan-3-one (2) and 3-hexyl-4,5-dithiocycloheptanone (3). Our results showed that all three compounds inhibited M1 activation of macrophages by down regulating the production of pro-inflammatory cytokines TNFα, IL-6 and IL-12, suppressed the expression of the NO converting enzyme iNOS, and enhanced expression of the M2 activation markers Arginase1 and MRC1. Moreover, disulfides 1 and 2 suppressed the expression of glucose transporters GLUT1 and GLUT3, suggesting that compounds 1 and 2 may affect cell metabolism. We showed that this was due to AKT/MAPK/ERK signaling pathway modulation and specifically by elevated AKT phosphorylation and MAPK/ERK signal transduction reduction. Hence, disulfides 1-3 can be considered as potent candidates for the development of novel anti-inflammatory molecules with homeostatic properties.

Enhanced neurogenesis is involved in neuroprotection provided by rottlerin against trimethyltin-induced delayed apoptotic neuronal damage

AIMS

We here investigated the effect of late- and post-ictal treatment with rottlerin, a polyphenol compound isolated from Mallotus philippinensis, on delayed apoptotic neuronal death induced by trimethyltin (TMT) in mice.

MAIN METHODS

Male C57BL/6N mice received a single injection of TMT (2.4 mg/kg, i.p.), and mice were treated with rottlerin after a peak time (i.e., 2 d post-TMT) of convulsive behaviors and apoptotic cell death (5.0 mg/kg, i.p. at 3 and 4 d after TMT injection). Object location test and tail suspension test were performed at 5 d after TMT injection. In addition, changes in the expression of apoptotic and neurogenic markers in the dentate gyrus were examined.

KEY FINDINGS

Late- and post-ictal treatment with rottlerin suppressed delayed neuronal apoptosis in the dentate gyrus, and attenuated memory impairments (as evaluated by object location test) and depression-like behaviors (as evaluated by tail suspension test) at 5 days after TMT injection in mice. In addition, rottlerin enhanced the expression of Sox2 and DCX, and facilitated p-ERK expression in BrdU-incorporated cells in the dentate gyrus of TMT-treated mice. Rottlerin also increased p-Akt expression, and attenuated the increase in the ratio of pro-apoptotic factors/anti-apoptotic factors, and consequent cytosolic cytochrome c release and caspase-3 cleavage. Rottlerin-mediated action was significantly reversed by SL327, an ERK inhibitor.

SIGNIFICANCE

Our results suggest that late- and post-ictal treatment with rottlerin attenuates TMT-induced delayed neuronal apoptosis in the dentate gyrus of mice via promotion of neurogenesis and inhibition of an on-going apoptotic process through up-regulation of p-ERK.

The MEK/ERK Module Is Reprogrammed in Remodeling Adult Cardiomyocytes

Fetal and hypertrophic remodeling are hallmarks of cardiac restructuring leading chronically to heart failure. Since the Ras/Raf/MEK/ERK cascade (MAPK) is involved in the development of heart failure, we hypothesized, first, that fetal remodeling is different from hypertrophy and, second, that remodeling of the MAPK occurs. To test our hypothesis, we analyzed models of cultured adult rat cardiomyocytes as well as investigated myocytes in the failing human myocardium by western blot and confocal microscopy. Fetal remodeling was induced through endothelial morphogens and monitored by the reexpression of Acta2, Actn1, and Actb. Serum-induced hypertrophy was determined by increased surface size and protein content of cardiomyocytes. Serum and morphogens caused reprogramming of Ras/Raf/MEK/ERK. In both models H-Ras, N-Ras, Rap2, B- and C-Raf, MEK1/2 as well as ERK1/2 increased while K-Ras was downregulated. Atrophy, MAPK-dependent ischemic resistance, loss of A-Raf, and reexpression of Rap1 and Erk3 highlighted fetal remodeling, while A-Raf accumulation marked hypertrophy. The knock-down of B-Raf by siRNA reduced MAPK activation and fetal reprogramming. In conclusion, we demonstrate that fetal and hypertrophic remodeling are independent processes and involve reprogramming of the MAPK.

Growth factor receptor bound protein-7 regulates proliferation, cell cycle, and mitochondrial apoptosis of thyroid cancer cells via MAPK/ERK signaling

It is of great significance to explore the molecular mechanism of thyroid cancer (TC) pathogenesis for its improvement and therapy. Growth factor receptor bound protein-7 (GRB7) has been regarded as an important regulatory gene in the developments of various malignant tumors. Our study aimed to illustrate the role of GRB7 in the TC pathology mechanism. Firstly, GRB7 was found to be significantly upregulated in 49 cases of TC tissues and 5 TC cell lines by using real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting. Silencing GRB7 with siRNA dramatically inhibited proliferation and induced cell cycle arrest in TC cells. Besides, GRB7 silence resulted in the decrease of adenosine triphosphate content, glucose uptake, and lactose production in TC cells and attenuated the activity and expression of mitochondrial respiratory complex. We also demonstrated that GRB7 downregulation increased the levels of Bax and caspase 3, and inhibited the expression of Bcl-2, suggesting the induced mitochondrial apoptosis. More importantly, our study proved that mitogen-activated protein kinase/extracellular-regulated protein kinases (MAPK/ERK) signaling played a crucial role in the regulation of GRB7 on TC cell functions. In general, the present research verified that GRB7 was upregulated during TC development and modulated the proliferation, cell cycle, and mitochondrial apoptosis of TC cells by activating MAPK/ERK pathway. This may provide a novel target for the therapeutic strategy of TC.

Selective Killing of RAS-Malignant Tissues by Exploiting Oncogene-Induced DNA Damage

Several oncogenes induce untimely entry into S phase and alter replication timing and progression, thereby generating replicative stress, a well-known source of genomic instability and a hallmark of cancer. Using an epithelial model in Drosophila, we show that the RAS oncogene, which triggers G1/S transition, induces DNA damage and, at the same time, silences the DNA damage response pathway. RAS compromises ATR-mediated phosphorylation of the histone variant H2Av and ATR-mediated cell-cycle arrest in G2 and blocks, through ERK, Dp53-dependent induction of cell death. We found that ERK is also activated in normal tissues by an exogenous source of damage and that this activation is necessary to dampen the pro-apoptotic role of Dp53. We exploit the pro-survival role of ERK activation upon endogenous and exogenous sources of DNA damage to present evidence that its genetic or chemical inhibition can be used as a therapeutic opportunity to selectively eliminate RAS-malignant tissues.

Growth Inhibitory Signaling of the Raf/MEK/ERK Pathway

In response to extracellular stimuli, the Raf/MEK/extracellular signal-regulated kinase (ERK) pathway regulates diverse cellular processes. While mainly known as a mitogenic signaling pathway, the Raf/MEK/ERK pathway can mediate not only cell proliferation and survival but also cell cycle arrest and death in different cell types. Growing evidence suggests that the cell fate toward these paradoxical physiological outputs may be determined not only at downstream effector levels but also at the pathway level, which involves the magnitude of pathway activity, spatial-temporal regulation, and non-canonical functions of the molecular switches in this pathway. This review discusses recent updates on the molecular mechanisms underlying the pathway-mediated growth inhibitory signaling, with a major focus on the regulation mediated at the pathway level.