International Journal of Molecular Sciences

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Open AccessEditorial

Mitogen-Activated Protein Kinases: Functions in Signal Transduction and Human Diseases

by Ritva Tikkanen and David J. Nikolic-Paterson

Int. J. Mol. Sci. 2019, 20(19), 4844; https://doi.org/10.3390/ijms20194844 - 29 Sep 2019

Cited by 14 | Viewed by 2003

Abstract

Mitogen-activated protein kinases (MAPKs) are involved in signaling processes induced by various stimuli, such as growth factors, stress, or even autoantibodies [...] Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

Research

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11 pages, 2956 KiB

Open AccessCommunication

Crosstalk between p38 and Erk 1/2 in Downregulation of FGF1-Induced Signaling

by Malgorzata Zakrzewska, Lukasz Opalinski, Ellen M. Haugsten, Jacek Otlewski and Antoni Wiedlocha

Int. J. Mol. Sci. 2019, 20(8), 1826; https://doi.org/10.3390/ijms20081826 - 12 Apr 2019

Cited by 15 | Viewed by 5456

Abstract

Mitogen-activated protein kinases (MAPK): Erk1 and Erk2 are key players in negative-feedback regulation of fibroblast growth factor (FGF) signaling. Upon activation, Erk1 and Erk2 directly phosphorylate FGF receptor 1 (FGFR1) at a specific serine residue in the C-terminal part of the receptor, substantially [...] Read more.

Mitogen-activated protein kinases (MAPK): Erk1 and Erk2 are key players in negative-feedback regulation of fibroblast growth factor (FGF) signaling. Upon activation, Erk1 and Erk2 directly phosphorylate FGF receptor 1 (FGFR1) at a specific serine residue in the C-terminal part of the receptor, substantially reducing the tyrosine phosphorylation in the receptor kinase domain and its signaling. Similarly, active Erks can also phosphorylate multiple threonine residues in the docking protein FGF receptor substrate 2 (FRS2), a major mediator of FGFR signaling. Here, we demonstrate that in NIH3T3 mouse fibroblasts and human osteosarcoma U2OS cells stably expressing FGFR1, in addition to Erk1 and Erk2, p38 kinase is able to phosphorylate FRS2. Simultaneous inhibition of Erk1/2 and p38 kinase led to a significant change in the phosphorylation pattern of FRS2 that in turn resulted in prolonged tyrosine phosphorylation of FGFR1 and FRS2 and in sustained signaling, as compared to the selective inhibition of Erks. Furthermore, excessive activation of p38 with anisomycin partially compensated the lack of Erks activity. These experiments reveal a novel crosstalk between p38 and Erk1/2 in downregulation of FGF-induced signaling. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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20 pages, 80991 KiB

Open AccessArticle

A Ruthenium(II) N-Heterocyclic Carbene (NHC) Complex with Naphthalimide Ligand Triggers Apoptosis in Colorectal Cancer Cells via Activating the ROS-p38 MAPK Pathway

by Yasamin Dabiri, Alice Schmid, Jannick Theobald, Biljana Blagojevic, Wojciech Streciwilk, Ingo Ott, Stefan Wölfl and Xinlai Cheng

Int. J. Mol. Sci. 2018, 19(12), 3964; https://doi.org/10.3390/ijms19123964 - 9 Dec 2018

Cited by 29 | Viewed by 5919

Abstract

The p38 MAPK pathway is known to influence the anti-tumor effects of several chemotherapeutics, including that of organometallic drugs. Previous studies have demonstrated the important role of p38 both as a regulator and a sensor of cellular reactive oxygen species (ROS) levels. Investigating [...] Read more.

The p38 MAPK pathway is known to influence the anti-tumor effects of several chemotherapeutics, including that of organometallic drugs. Previous studies have demonstrated the important role of p38 both as a regulator and a sensor of cellular reactive oxygen species (ROS) levels. Investigating the anti-cancer properties of novel 1,8-naphthalimide derivatives containing Rh(I) and Ru(II) N-heterocyclic carbene (NHC) ligands, we observed a profound induction of ROS by the complexes, which is most likely generated from mitochondria (mtROS). Further analyses revealed a rapid and consistent activation of p38 signaling by the naphthalimide-NHC conjugates, with the Ru(II) analogue—termed MC6—showing the strongest effect. In view of this, genetic as well as pharmacological inhibition of p38α, attenuated the anti-proliferative and pro-apoptotic effects of MC6 in HCT116 colon cancer cells, highlighting the involvement of this signaling molecule in the compound’s toxicity. Furthermore, the influence of MC6 on p38 signaling appeared to be dependent on ROS levels as treatment with general- and mitochondria-targeted anti-oxidants abrogated p38 activation in response to MC6 as well as the molecule’s cytotoxic- and apoptogenic response in HCT116 cells. Altogether, our results provide new insight into the molecular mechanisms of naphthalimide-metal NHC analogues via the ROS-induced activation of p38 MAPK, which may have therapeutic interest for the treatment of various cancer types. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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22 pages, 5124 KiB

Open AccessArticle

Scutellariae Radix and Coptidis Rhizoma Improve Glucose and Lipid Metabolism in T2DM Rats via Regulation of the Metabolic Profiling and MAPK/PI3K/Akt Signaling Pathway

by Xiang Cui, Da-Wei Qian, Shu Jiang, Er-Xin Shang, Zhen-Hua Zhu and Jin-Ao Duan

Int. J. Mol. Sci. 2018, 19(11), 3634; https://doi.org/10.3390/ijms19113634 - 18 Nov 2018

Cited by 166 | Viewed by 10105

Abstract

Aim Scutellariae Radix (SR) and Coptidis Rhizoma (CR) have often been combined to cure type 2 diabetes mellitus (T2DM) in the clinical practice for over thousands of years, but their compatibility mechanism is not clear. Mitogen-activated protein kinase (MAPK) signaling pathway has been [...] Read more.

Aim Scutellariae Radix (SR) and Coptidis Rhizoma (CR) have often been combined to cure type 2 diabetes mellitus (T2DM) in the clinical practice for over thousands of years, but their compatibility mechanism is not clear. Mitogen-activated protein kinase (MAPK) signaling pathway has been suggested to play a critical role during the process of inflammation, insulin resistance, and T2DM. This study was designed to investigate their compatibility effects on T2DM rats and explore the underlying mechanisms by analyzing the metabolic profiling and MAPK/PI3K/Akt signaling pathway. Methods The compatibility effects of SR and CR were evaluated with T2DM rats induced by a high-fat diet (HFD) along with a low dose of streptozocin (STZ). Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was performed to discover potential biomarkers. The levels of pro-inflammatory cytokines; biochemical indexes in serum, and the activities of key enzymes related to glycometabolism in liver were assessed by ELISA kits. qPCR was applied to examine mRNA levels of key targets in MAPK and insulin signaling pathways. Protein expressions of p65; p-p65; phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K); phosphorylated-PI3K (p-PI3K); protein kinase B (Akt); phosphorylated Akt (p-Akt) and glucose transporter 2 (Glut2) in liver were investigated by Western blot analysis. Results Remarkably, hyperglycaemia, dyslipidemia, inflammation, and insulin resistance in T2DM were ameliorated after oral administration of SR and CR, particularly their combined extracts. The effects of SR, CR, low dose of combined extracts (LSC) and high dose of combined extracts (HSC) on pro-inflammatory cytokine transcription in T2DM rats showed that the MAPK pathway might account for the phenomenon with down-regulation of MAPK (P38 mitogen-activated protein kinases (P38), extracellular regulated protein kinases (ERK), and c-Jun N-terminal kinase (JNK)) mRNA, and protein reduction in p-P65. While mRNA levels of key targets such as insulin receptor substrate 1 (IRS1), PI3K, Akt2, and Glut2 in the insulin signaling pathway were notably up-modulated, phosphorylations of PI3K, Akt, and expression of Glut2 were markedly enhanced. Moreover, the increased activities of phosphoenolpyruvate carboxykinase (PEPCK), fructose-1,6-bisphosphatase (FBPase), glucose 6-phosphatase (G6Pase), and glycogen phosphorylase (GP) were highly reduced and the decreased activities of glucokinase (GK), phosphofructokinase (PFK), pyruvate kinase (PK), and glycogen synthase (GS) in liver were notably increased after treatment. Further investigation indicated that the metabolic profiles of plasma and urine were clearly improved in T2DM rats. Fourteen potential biomarkers (nine in plasma and five in urine) were identified. After intervention, these biomarkers returned to normal level to some extent. Conclusion The results showed that SR, CR, and combined extract groups were normalized. The effects of combined extracts were more remarkable than single herb treatment. Additionally, this study also showed that the metabonomics method is a promising tool to unravel how traditional Chinese medicines work. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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16 pages, 2491 KiB

Open AccessArticle

Novel Functions of Death-Associated Protein Kinases through Mitogen-Activated Protein Kinase-Related Signals

by Mohamed Elbadawy, Tatsuya Usui, Hideyuki Yamawaki and Kazuaki Sasaki

Int. J. Mol. Sci. 2018, 19(10), 3031; https://doi.org/10.3390/ijms19103031 - 4 Oct 2018

Cited by 32 | Viewed by 8851 | Correction

Abstract

Death associated protein kinase (DAPK) is a calcium/calmodulin-regulated serine/threonine kinase; its main function is to regulate cell death. DAPK family proteins consist of DAPK1, DAPK2, DAPK3, DAPK-related apoptosis-inducing protein kinases (DRAK)-1 and DRAK-2. In this review, we discuss the roles and regulatory mechanisms [...] Read more.

Death associated protein kinase (DAPK) is a calcium/calmodulin-regulated serine/threonine kinase; its main function is to regulate cell death. DAPK family proteins consist of DAPK1, DAPK2, DAPK3, DAPK-related apoptosis-inducing protein kinases (DRAK)-1 and DRAK-2. In this review, we discuss the roles and regulatory mechanisms of DAPK family members and their relevance to diseases. Furthermore, a special focus is given to several reports describing cross-talks between DAPKs and mitogen-activated protein kinases (MAPK) family members in various pathologies. We also discuss small molecule inhibitors of DAPKs and their potential as therapeutic targets against human diseases. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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16 pages, 9230 KiB

Open AccessArticle

Effects of Sunitinib and Other Kinase Inhibitors on Cells Harboring a PDGFRB Mutation Associated with Infantile Myofibromatosis

by Martin Sramek, Jakub Neradil, Petra Macigova, Peter Mudry, Kristyna Polaskova, Ondrej Slaby, Hana Noskova, Jaroslav Sterba and Renata Veselska

Int. J. Mol. Sci. 2018, 19(9), 2599; https://doi.org/10.3390/ijms19092599 - 1 Sep 2018

Cited by 17 | Viewed by 5465

Abstract

Infantile myofibromatosis represents one of the most common proliferative fibrous tumors of infancy and childhood. More effective treatment is needed for drug-resistant patients, and targeted therapy using specific protein kinase inhibitors could be a promising strategy. To date, several studies have confirmed a [...] Read more.

Infantile myofibromatosis represents one of the most common proliferative fibrous tumors of infancy and childhood. More effective treatment is needed for drug-resistant patients, and targeted therapy using specific protein kinase inhibitors could be a promising strategy. To date, several studies have confirmed a connection between the p.R561C mutation in gene encoding platelet-derived growth factor receptor beta (PDGFR-beta) and the development of infantile myofibromatosis. This study aimed to analyze the phosphorylation of important kinases in the NSTS-47 cell line derived from a tumor of a boy with infantile myofibromatosis who harbored the p.R561C mutation in PDGFR-beta. The second aim of this study was to investigate the effects of selected protein kinase inhibitors on cell signaling and the proliferative activity of NSTS-47 cells. We confirmed that this tumor cell line showed very high phosphorylation levels of PDGFR-beta, extracellular signal-regulated kinases (ERK) 1/2 and several other protein kinases. We also observed that PDGFR-beta phosphorylation in tumor cells is reduced by the receptor tyrosine kinase inhibitor sunitinib. In contrast, MAPK/ERK kinases (MEK) 1/2 and ERK1/2 kinases remained constitutively phosphorylated after treatment with sunitinib and other relevant protein kinase inhibitors. Our study showed that sunitinib is a very promising agent that affects the proliferation of tumor cells with a p.R561C mutation in PDGFR-beta. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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11 pages, 1359 KiB

Open AccessCommunication

ERK5 Phosphorylates K_v4.2 and Inhibits Inactivation of the A-Type Current in PC12 Cells

by Yurina Kashino, Yutaro Obara, Yosuke Okamoto, Takeo Saneyoshi, Yasunori Hayashi and Kuniaki Ishii

Int. J. Mol. Sci. 2018, 19(7), 2008; https://doi.org/10.3390/ijms19072008 - 10 Jul 2018

Cited by 7 | Viewed by 3387

Abstract

Extracellular signal-regulated kinase 5 (ERK5) regulates diverse physiological responses such as proliferation, differentiation, and gene expression. Previously, we demonstrated that ERK5 is essential for neurite outgrowth and catecholamine biosynthesis in PC12 cells and sympathetic neurons. However, it remains unclear how ERK5 regulates the [...] Read more.

Extracellular signal-regulated kinase 5 (ERK5) regulates diverse physiological responses such as proliferation, differentiation, and gene expression. Previously, we demonstrated that ERK5 is essential for neurite outgrowth and catecholamine biosynthesis in PC12 cells and sympathetic neurons. However, it remains unclear how ERK5 regulates the activity of ion channels, which are important for membrane excitability. Thus, we examined the effect of ERK5 on the ion channel activity in the PC12 cells that overexpress both ERK5 and the constitutively active MEK5 mutant. The gene and protein expression levels of voltage-dependent Ca²⁺ and K⁺ channels were determined by RT-qPCR or Western blotting. The A-type K⁺ current was recorded using the whole-cell patch clamp method. In these ERK5-activated cells, the gene expression levels of voltage-dependent L- and P/Q-type Ca²⁺ channels did not alter, but the N-type Ca²⁺ channel was slightly reduced. In contrast, those of K_v4.2 and K_v4.3, which are components of the A-type current, were significantly enhanced. Unexpectedly, the protein levels of K_v4.2 were not elevated by ERK5 activation, but the phosphorylation levels were increased by ERK5 activation. By electrophysiological analysis, the inactivation time constant of the A-type current was prolonged by ERK5 activation, without changes in the peak current. Taken together, ERK5 inhibits an inactivation of the A-type current by phosphorylation of K_v4.2, which may contribute to the neuronal differentiation process. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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13 pages, 5381 KiB

Open AccessArticle

Cecropin A Modulates Tight Junction-Related Protein Expression and Enhances the Barrier Function of Porcine Intestinal Epithelial Cells by Suppressing the MEK/ERK Pathway

by Zhenya Zhai, Xiaojun Ni, Chenglong Jin, Wenkai Ren, Jie Li, Jinping Deng, Baichuan Deng and Yulong Yin

Int. J. Mol. Sci. 2018, 19(7), 1941; https://doi.org/10.3390/ijms19071941 - 2 Jul 2018

Cited by 40 | Viewed by 6471

Abstract

Inflammatory bowel disease (IBD) in humans and animals is associated with bacterial infection and intestinal barrier dysfunction. Cecropin A, an antimicrobial peptide, has antibacterial activity against pathogenic bacteria. However, the effect of cecropin A on intestinal barrier function and its related mechanisms is [...] Read more.

Inflammatory bowel disease (IBD) in humans and animals is associated with bacterial infection and intestinal barrier dysfunction. Cecropin A, an antimicrobial peptide, has antibacterial activity against pathogenic bacteria. However, the effect of cecropin A on intestinal barrier function and its related mechanisms is still unclear. Here, we used porcine jejunum epithelial cells (IPEC-J2) as a model to investigate the effect and mechanism of cecropin A on intestinal barrier function. We found that cecropin A reduced Escherichia coli (E. coli) adherence to IPEC-J2 cells and downregulated mRNA expression of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8). Furthermore, cecropin A elevated the transepithelial electrical resistance (TER) value while reducing the paracellular permeability of the IPEC-J2 cell monolayer barrier. Finally, by using Western blotting, immunofluorescence and pathway-specific antagonists, we demonstrated that cecropin A increased ZO-1, claudin-1 and occludin protein expression and regulated membrane distribution and F-actin polymerization by increasing CDX2 expression. We conclude that cecropin A enhances porcine intestinal epithelial cell barrier function by downregulating the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. We suggest that cecropin A has the potential to replace antibiotics in the treatment of IBD due to its antibacterial activity on gram-negative bacteria and its enhancement effect on intestinal barrier function. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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20 pages, 4290 KiB

Open AccessArticle

Sirt1 Protects against Oxidative Stress-Induced Apoptosis in Fibroblasts from Psoriatic Patients: A New Insight into the Pathogenetic Mechanisms of Psoriasis

by Matteo Becatti, Victoria Barygina, Amanda Mannucci, Giacomo Emmi, Domenico Prisco, Torello Lotti, Claudia Fiorillo and Niccolò Taddei

Int. J. Mol. Sci. 2018, 19(6), 1572; https://doi.org/10.3390/ijms19061572 - 25 May 2018

Cited by 53 | Viewed by 5600

Abstract

Psoriasis, a multisystem chronic disease characterized by abnormal keratinocyte proliferation, has an unclear pathogenesis where systemic inflammation and oxidative stress play mutual roles. Dermal fibroblasts, which are known to provide a crucial microenvironment for epidermal keratinocyte function, represented the selected experimental model in [...] Read more.

Psoriasis, a multisystem chronic disease characterized by abnormal keratinocyte proliferation, has an unclear pathogenesis where systemic inflammation and oxidative stress play mutual roles. Dermal fibroblasts, which are known to provide a crucial microenvironment for epidermal keratinocyte function, represented the selected experimental model in our study which aimed to clarify the potential role of SIRT1 in the pathogenetic mechanisms of the disease. We firstly detected the presence of oxidative stress (lipid peroxidation and total antioxidant capacity), significantly reduced SIRT1 expression level and activity, mitochondrial damage and apoptosis (caspase-3, -8 and -9 activities) in psoriatic fibroblasts. Upon SIRT1 activation, redox balance was re-established, mitochondrial function was restored and apoptosis was no longer evident. Furthermore, we examined p38, ERK and JNK activation, which was strongly altered in psoriatic fibroblasts, in response to SIRT1 activation and we measured caspase-3 activity in the presence of specific MAPK inhibitors demonstrating the key role of the SIRT1 pathway against apoptotic cell death via MAPK modulation. Our results clearly demonstrate the involvement of SIRT1 in the protective mechanisms related to fibroblast injury in psoriasis. SIRT1 activation exerts an active role in restoring both mitochondrial function and redox balance via modulation of MAPK signaling. Hence, SIRT1 can be proposed as a specific tool for the treatment of psoriasis. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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17 pages, 4679 KiB

Open AccessArticle

Hyperoxia Disrupts Extracellular Signal-Regulated Kinases 1/2-Induced Angiogenesis in the Developing Lungs

by Renuka T. Menon, Amrit Kumar Shrestha, Roberto Barrios and Binoy Shivanna

Int. J. Mol. Sci. 2018, 19(5), 1525; https://doi.org/10.3390/ijms19051525 - 20 May 2018

Cited by 12 | Viewed by 4762

Abstract

Hyperoxia contributes to the pathogenesis of bronchopulmonary dysplasia (BPD), a chronic lung disease of infants that is characterized by interrupted alveologenesis. Disrupted angiogenesis inhibits alveologenesis, but the mechanisms of disrupted angiogenesis in the developing lungs are poorly understood. In pre-clinical BPD models, hyperoxia [...] Read more.

Hyperoxia contributes to the pathogenesis of bronchopulmonary dysplasia (BPD), a chronic lung disease of infants that is characterized by interrupted alveologenesis. Disrupted angiogenesis inhibits alveologenesis, but the mechanisms of disrupted angiogenesis in the developing lungs are poorly understood. In pre-clinical BPD models, hyperoxia increases the expression of extracellular signal-regulated kinases (ERK) 1/2; however, its effects on the lung endothelial ERK1/2 signaling are unclear. Further, whether ERK1/2 activation promotes lung angiogenesis in infants is unknown. Hence, we tested the following hypotheses: (1) hyperoxia exposure will increase lung endothelial ERK1/2 signaling in neonatal C57BL/6J (WT) mice and in fetal human pulmonary artery endothelial cells (HPAECs); (2) ERK1/2 inhibition will disrupt angiogenesis in vitro by repressing cell cycle progression. In mice, hyperoxia exposure transiently increased lung endothelial ERK1/2 activation at one week of life, before inhibiting it at two weeks of life. Interestingly, hyperoxia-mediated decrease in ERK1/2 activation in mice was associated with decreased angiogenesis and increased endothelial cell apoptosis. Hyperoxia also transiently activated ERK1/2 in HPAECs. ERK1/2 inhibition disrupted angiogenesis in vitro, and these effects were associated with altered levels of proteins that modulate cell cycle progression. Collectively, these findings support our hypotheses, emphasizing that the ERK1/2 pathway is a potential therapeutic target for BPD infants with decreased lung vascularization. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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15 pages, 4350 KiB

Open AccessArticle

Anti-Inflammatory and Gastroprotective Roles of Rabdosia inflexa through Downregulation of Pro-Inflammatory Cytokines and MAPK/NF-κB Signaling Pathways

by Md Rashedunnabi Akanda, In-Shik Kim, Dongchoon Ahn, Hyun-Jin Tae, Hyeon-Hwa Nam, Byung-Kil Choo, Kyunghwa Kim and Byung-Yong Park

Int. J. Mol. Sci. 2018, 19(2), 584; https://doi.org/10.3390/ijms19020584 - 14 Feb 2018

Cited by 65 | Viewed by 6428 | Correction

Abstract

Globally, gastric ulcer is a vital health hazard for a human. Rabdosia inflexa (RI) has been used in traditional medicine for inflammatory diseases. The present study aimed to investigate the protective effect and related molecular mechanism of RI using lipopolysaccharide (LPS)-induced inflammation in [...] Read more.

Globally, gastric ulcer is a vital health hazard for a human. Rabdosia inflexa (RI) has been used in traditional medicine for inflammatory diseases. The present study aimed to investigate the protective effect and related molecular mechanism of RI using lipopolysaccharide (LPS)-induced inflammation in RAW 246.7 cells and HCl/EtOH-induced gastric ulcer in mice. We applied 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), nitric oxide (NO), reactive oxygen species (ROS), histopathology, malondialdehyde (MDA), quantitative real-time polymerase chain reaction (qPCR), immunohistochemistry (IHC), and Western blot analyses to evaluate the protective role of RI. Study revealed that RI effectively attenuated LPS-promoted NO and ROS production in RAW 246.7 cells. In addition, RI mitigated gastric oxidative stress by inhibiting lipid peroxidation, elevating NO, and decreasing gastric inflammation. RI significantly halted elevated gene expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthetase (iNOS), and cyclooxygenase-2 (COX-2) in gastric tissue. Likewise, RI markedly attenuated the mitogen-activated protein kinases (MAPKs) phosphorylation, COX-2 expression, phosphorylation and degradation of inhibitor kappa B (IκBα) and activation of nuclear factor kappa B (NF-κB). Thus, experimental findings suggested that the anti-inflammatory and gastroprotective activities of RI might contribute to regulating pro-inflammatory cytokines and MAPK/NF-κB signaling pathways. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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Review

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20 pages, 980 KiB

Open AccessReview

Role of p38 MAPK in Atherosclerosis and Aortic Valve Sclerosis

by Anna Reustle and Michael Torzewski

Int. J. Mol. Sci. 2018, 19(12), 3761; https://doi.org/10.3390/ijms19123761 - 27 Nov 2018

Cited by 123 | Viewed by 6531

Abstract

Atherosclerosis and aortic valve sclerosis are cardiovascular diseases with an increasing prevalence in western societies. Statins are widely applied in atherosclerosis therapy, whereas no pharmacological interventions are available for the treatment of aortic valve sclerosis. Therefore, valve replacement surgery to prevent acute heart [...] Read more.

Atherosclerosis and aortic valve sclerosis are cardiovascular diseases with an increasing prevalence in western societies. Statins are widely applied in atherosclerosis therapy, whereas no pharmacological interventions are available for the treatment of aortic valve sclerosis. Therefore, valve replacement surgery to prevent acute heart failure is the only option for patients with severe aortic stenosis. Both atherosclerosis and aortic valve sclerosis are not simply the consequence of degenerative processes, but rather diseases driven by inflammatory processes in response to lipid-deposition in the blood vessel wall and the aortic valve, respectively. The p38 mitogen-activated protein kinase (MAPK) is involved in inflammatory signaling and activated in response to various intracellular and extracellular stimuli, including oxidative stress, cytokines, and growth factors, all of which are abundantly present in atherosclerotic and aortic valve sclerotic lesions. The responses generated by p38 MAPK signaling in different cell types present in the lesions are diverse and might support the progression of the diseases. This review summarizes experimental findings relating to p38 MAPK in atherosclerosis and aortic valve sclerosis and discusses potential functions of p38 MAPK in the diseases with the aim of clarifying its eligibility as a pharmacological target. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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14 pages, 835 KiB

Open AccessReview

The Regulation of JNK Signaling Pathways in Cell Death through the Interplay with Mitochondrial SAB and Upstream Post-Translational Effects

by Sanda Win, Tin Aung Than and Neil Kaplowitz

Int. J. Mol. Sci. 2018, 19(11), 3657; https://doi.org/10.3390/ijms19113657 - 20 Nov 2018

Cited by 52 | Viewed by 6628

Abstract

c-Jun-N-terminal kinase (JNK) activity plays a critical role in modulating cell death, which depends on the level and duration of JNK activation. The kinase cascade from MAPkinase kinase kinase (MAP3K) to MAPkinase kinase (MAP2K) to MAPKinase (MAPK) can be regulated by a number [...] Read more.

c-Jun-N-terminal kinase (JNK) activity plays a critical role in modulating cell death, which depends on the level and duration of JNK activation. The kinase cascade from MAPkinase kinase kinase (MAP3K) to MAPkinase kinase (MAP2K) to MAPKinase (MAPK) can be regulated by a number of direct and indirect post-transcriptional modifications, including acetylation, ubiquitination, phosphorylation, and their reversals. Recently, a JNK-mitochondrial SH3-domain binding protein 5 (SH3BP5/SAB)-ROS activation loop has been elucidated, which is required to sustain JNK activity. Importantly, the level of SAB expression in the outer membrane of mitochondria is a major determinant of the set-point for sustained JNK activation. SAB is a docking protein and substrate for JNK, leading to an intramitochondrial signal transduction pathway, which impairs electron transport and promotes reactive oxygen species (ROS) release to sustain the MAPK cascade. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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21 pages, 3546 KiB

Open AccessReview

The Importance of the Right Framework: Mitogen-Activated Protein Kinase Pathway and the Scaffolding Protein PTPIP51

by Eric Dietel, Alexander Brobeil, Stefan Gattenlöhner and Monika Wimmer

Int. J. Mol. Sci. 2018, 19(10), 3282; https://doi.org/10.3390/ijms19103282 - 22 Oct 2018

Cited by 7 | Viewed by 5564

Abstract

The protein tyrosine phosphatase interacting protein 51 (PTPIP51) regulates and interconnects signaling pathways, such as the mitogen-activated protein kinase (MAPK) pathway and an abundance of different others, e.g., Akt signaling, NF-κB signaling, and the communication between different cell organelles. PTPIP51 acts as a [...] Read more.

The protein tyrosine phosphatase interacting protein 51 (PTPIP51) regulates and interconnects signaling pathways, such as the mitogen-activated protein kinase (MAPK) pathway and an abundance of different others, e.g., Akt signaling, NF-κB signaling, and the communication between different cell organelles. PTPIP51 acts as a scaffold protein for signaling proteins, e.g., Raf-1, epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (Her2), as well as for other scaffold proteins, e.g., 14-3-3 proteins. These interactions are governed by the phosphorylation of serine and tyrosine residues of PTPIP51. The phosphorylation status is finely tuned by receptor tyrosine kinases (EGFR, Her2), non-receptor tyrosine kinases (c-Src) and the phosphatase protein tyrosine phosphatase 1B (PTP1B). This review addresses various diseases which display at least one alteration in these enzymes regulating PTPIP51-interactions. The objective of this review is to summarize the knowledge of the MAPK-related interactome of PTPIP51 for several tumor entities and metabolic disorders. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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20 pages, 1072 KiB

Open AccessReview

Roles of Mitogen-Activated Protein Kinases in Osteoclast Biology

by Kyunghee Lee, Incheol Seo, Mun Hwan Choi and Daewon Jeong

Int. J. Mol. Sci. 2018, 19(10), 3004; https://doi.org/10.3390/ijms19103004 - 1 Oct 2018

Cited by 169 | Viewed by 9167

Abstract

Bone undergoes continuous remodeling, which is homeostatically regulated by concerted communication between bone-forming osteoblasts and bone-degrading osteoclasts. Multinucleated giant osteoclasts are the only specialized cells that degrade or resorb the organic and inorganic bone components. They secrete proteases (e.g., cathepsin K) that degrade [...] Read more.

Bone undergoes continuous remodeling, which is homeostatically regulated by concerted communication between bone-forming osteoblasts and bone-degrading osteoclasts. Multinucleated giant osteoclasts are the only specialized cells that degrade or resorb the organic and inorganic bone components. They secrete proteases (e.g., cathepsin K) that degrade the organic collagenous matrix and establish localized acidosis at the bone-resorbing site through proton-pumping to facilitate the dissolution of inorganic mineral. Osteoporosis, the most common bone disease, is caused by excessive bone resorption, highlighting the crucial role of osteoclasts in intact bone remodeling. Signaling mediated by mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, has been recognized to be critical for normal osteoclast differentiation and activation. Various exogenous (e.g., toll-like receptor agonists) and endogenous (e.g., growth factors and inflammatory cytokines) stimuli contribute to determining whether MAPKs positively or negatively regulate osteoclast adhesion, migration, fusion and survival, and osteoclastic bone resorption. In this review, we delineate the unique roles of MAPKs in osteoclast metabolism and provide an overview of the upstream regulators that activate or inhibit MAPKs and their downstream targets. Furthermore, we discuss the current knowledge about the differential kinetics of ERK, JNK, and p38, and the crosstalk between MAPKs in osteoclast metabolism. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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17 pages, 622 KiB

Open AccessReview

Role of Mitogen Activated Protein Kinase Signaling in Parkinson’s Disease

by Anastasiia Bohush, Grazyna Niewiadomska and Anna Filipek

Int. J. Mol. Sci. 2018, 19(10), 2973; https://doi.org/10.3390/ijms19102973 - 29 Sep 2018

Cited by 109 | Viewed by 6951

Abstract

Parkinson’s disease (PD) is a neurodegenerative disorder caused by insufficient dopamine production due to the loss of 50% to 70% of dopaminergic neurons. A shortage of dopamine, which is predominantly produced by the dopaminergic neurons within the substantia nigra, causes clinical symptoms such [...] Read more.

Parkinson’s disease (PD) is a neurodegenerative disorder caused by insufficient dopamine production due to the loss of 50% to 70% of dopaminergic neurons. A shortage of dopamine, which is predominantly produced by the dopaminergic neurons within the substantia nigra, causes clinical symptoms such as reduction of muscle mass, impaired body balance, akinesia, bradykinesia, tremors, postural instability, etc. Lastly, this can lead to a total loss of physical movement and death. Since no cure for PD has been developed up to now, researchers using cell cultures and animal models focus their work on searching for potential therapeutic targets in order to develop effective treatments. In recent years, genetic studies have prominently advocated for the role of improper protein phosphorylation caused by a dysfunction in kinases and/or phosphatases as an important player in progression and pathogenesis of PD. Thus, in this review, we focus on the role of selected MAP kinases such as JNKs, ERK1/2, and p38 MAP kinases in PD pathology. Full article

(This article belongs to the Special Issue Mitogen Activated Protein Kinases: Functions in Signal Transduction and Human Diseases)

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