P38 MAPK Activation Research Articles

Lipopolysaccharide and ARDS caused by new coronavirus infection: hypotheses and facts

This review presents data from the literature that provide insight into the role of the lipopolysaccharide (LPS) of the Gram-negative bacteria in pathogenesis of acute respiratory distress syndrome (ARDS) caused by the novel SARS-CoV-2 coronavirus infection. ARDS is a syndrome of severe respiratory failure, an acutely occurring diffuse inflammatory lesion of lung tissue that develops as a nonspecific reaction to various direct (aspiration, inhalation of toxic gases), and systemic (sepsis, polytrauma) damaging factors and leading to development of acute respiratory failure (ARF), due to impaired structure of the lung parenchyma, disturbances in vascular permeability, decreased area of ventilated lung tissue. ARDS from coronavirus infection appears to have worse outcomes than ARDS from other causes. Mortality from typical ARDS at the intensive care units and hospitals is 35.3% and 40.0%, respectively, while the lethality rates for COVID-19-associated ARDS, ranged from 26% to 61.5%. Among patients who underwent artificial ventilation of the lungs, the mortality rates can range from 65.7% to 94%. Risk factors for poor outcomes include, e.g., older age, presence of concomitant diseases such as hypertension, cardiovascular disease and diabetes mellitus; decreased number of lymphocytes, kidney injury, and increased D-dimer levels. Death with ARDS in COVID-19 occurs as a result of respiratory failure (53%), respiratory failure combined with heart failure (33%), myocardial damage and circulatory failure (7%), or death from an unknown cause. A large number of studies show that bacterial LPS is directly or indirectly involved in all pathogenetic links of ARDS caused by the SARS-CoV-2 virus, i.e., worsening the course of inflammatory lung diseases due to decreased level of angiotensin-converting enzyme 2 (ACE2); increasing generation of reactive oxygen species (ROS) via NADPH oxidase and subsequent inactivation of endothelial nitric oxide synthase (eNOS) and decreasing bioavailability of endothelial NO, thus leading to endothelial dysfunction; interacting with proteins of surfactants. SP-A and SP-D, promoting early destruction of the cellular monolayers and lowering surface tension, interact with soluble CD14 receptor, which also has a pro-inflammatory effect on epithelial and endothelial cells, leading to p38MAPK activation via TLR4 receptors, causing degradation of IêBá protein and subsequent translocation of p65 NF-êB into the nucleus, thus inducing transcription of IL-6 and adhesion molecules (ICAM-1, VCAM-1 and E-selectin), and, as shown by Petruk et al. (2020), causing direct binding to the viral S protein in combination with LPS, thus enhancing activation of nuclear factor-kappa B (NF-êB) in monocytic THP-1 cells and cytokine responses in mononuclear blood cells. These pathophysiological mechanisms require further in-depth study in order to understand the nature of changes that occur in the patients with new SARS-CoV-2 infection.

Targeted inhibition of ZAK ameliorates renal interstitial fibrosis

ZAK (sterile alpha motif and leucine zipper-containing kinase) is a newly discovered member of the subfamily of mitogen-activated protein kinase kinase kinases (MAP3Ks). The role of ZAK in kidney disease remains largely unknown. In this study, we systematically investigated the expression and function of ZAK in the progression of tubulointerstitial fibrosis (TIF). ZAK was induced, predominantly in tubular epithelium, in both fibrotic kidneys of human and mouse models with TIF. ZAK expression level was correlated with the extent of renal fibrosis and the decline of eGFR of CKD patients. Depleting ZAK attenuated TIF and inflammation induced by unilateral ureteral occlusion (UUO) together with decreased activation of p38 MAPK and Smads signaling. Moreover, we demonstrated that overexpressed ZAK was in complex with Smad2/3 and TGF-β receptor Ⅰ (TβRI). Whereas, silencing endogenous ZAK ameliorated the amount of Smad2/3 recruited to TβRI. Moreover, we discovered a novel small molecule inhibitor of ZAK, named 6p. In vitro, incubation with 6p inhibited TGF-β1-induced fibrogenic response in NRK52E cells. In vivo, intragastric administration of 6p ameliorated TIF and inflammation in UUO and unilateral ischemia-reperfusion injury model. Delayed administration of 6p was also effective in retarding the progression of the established TIF. In conclusion, ZAK is a novel therapeutic target for TIF, and 6p might be a potential therapeutic agent for TIF.

Melatonin improves bisphenol A-induced cell apoptosis, oxidative stress and autophagy impairment via inhibition of the p38 MAPK signaling pathway in FLK-BLV cells.

The aim of this study was to assess the protective effect and potential mechanism of melatonin against bisphenol A (BPA)-induced apoptosis and oxidative damage in FLK-BLV cells. The results showed that BPA reduced cell viability in a dose- and time-dependent manner, caused cell shrinkage and induced oxidative stress and apoptosis in FLK-BLV cells, which were effectively reversed by melatonin. In addition, BPA caused autophagy flux impairment, which was confirmed by the increased of LC3-II and p62 levels, whereas melatonin treatment effectively reduced p62 levels under BPA treatment, and reversed apoptosis-related protein expression patterns caused by BPA. However, inhibition of autophagy by CQ partially abolished the protective effect of melatonin on apoptosis, suggesting that melatonin against BPA-induced oxidative injury and apoptosis by activating autophagy pathway. Moreover, we found that melatonin inhibited BPA-induced the activation of p38 MAPK, which was comparable to SB203580 pretreatment, and companied by the activation of autophagy and decreases of apoptosis when compared to BPA alone, indicating that melatonin protected against BPA-induced apoptosis partially through the p38 MAPK-autophagy pathway. In conclusion, these results suggest that melatonin may prevent BPA-induced FLK-BLV cell damage by inhibiting p38/MAPK signaling pathway and activating autophagy, and it could be a potential therapeutic compound in preventing BPA-induced cell damage.

Angiotensin II Induces Cardiac Edema and Hypertrophic Remodeling through Lymphatic-Dependent Mechanisms.

Cardiac lymphatic vessel growth (lymphangiogenesis) and integrity play an essential role in maintaining tissue fluid balance. Inhibition of lymphatic lymphangiogenesis is involved in cardiac edema and cardiac remodeling after ischemic injury or pressure overload. However, whether lymphatic vessel integrity is disrupted during angiotensin II- (Ang II-) induced cardiac remodeling remains to be investigated. In this study, cardiac remodeling models were established by Ang II (1000 ng/kg/min) in VEGFR-3 knockdown (Lyve-1Cre VEGFR-3f/−) and wild-type (VEGFR-3f/f) littermates. Our results indicated that Ang II infusion not only induced cardiac lymphangiogenesis and upregulation of VEGF-C and VEGFR-3 expression in the time-dependent manner but also enhanced proteasome activity, MKP5 and VE-cadherin degradation, p38 MAPK activation, and lymphatic vessel hyperpermeability. Moreover, VEGFR-3 knockdown significantly inhibited cardiac lymphangiogenesis in mice, resulting in exacerbation of tissue edema, hypertrophy, fibrosis superoxide production, inflammation, and heart failure (HF). Conversely, administration of epoxomicin (a selective proteasome inhibitor) markedly mitigated Ang II-induced cardiac edema, remodeling, and dysfunction; upregulated MKP5 and VE-cadherin expression; inactivated p38 MAPK; and reduced lymphatic vessel hyperpermeability in WT mice, indicating that inhibition of proteasome activity is required to maintain lymphatic endothelial cell (LEC) integrity. Our results show that both cardiac lymphangiogenesis and lymphatic barrier hyperpermeability are implicated in Ang II-induced adaptive hypertrophic remodeling and dysfunction. Proteasome-mediated hyperpermeability of LEC junctions plays a predominant role in the development of cardiac remodeling. Selective stimulation of lymphangiogenesis or inhibition of proteasome activity may be a potential therapeutic option for treating hypertension-induced cardiac remodeling.

Myeloid differential protein-2 inhibition improves diabetic cardiomyopathy via p38MAPK inhibition and AMPK pathway activation

Myeloid differential protein-2 (MD2) has been shown to play a critical role in the progression of diabetic cardiomyopathy (DCM). This study aims to explore the non-inflammatory mechanisms mediated by MD2 in DCM and to test the therapeutic effects of MD2 inhibitor C30 on DCM. Streptozotocin (STZ) was used to construct DCM model in wild-type and MD2 knockout mice. The collected heart samples were subjected to RNA-sequencing assay. Gene set enrichment analysis of the RNA-seq data indicated that MD2 knockout was associated with energy metabolism pathways in diabetic mouse heart. Further data showed that AMPK pathway was impaired under high glucose condition, which was mediated by p38MAPK activation. MD2 knockout or pharmacological inhibitor C30 completely rescued AMPK signaling through p38MAPK inhibition. Importantly, C30 treatment significantly prevented myocardial damage and dysfunction in T1DM mice evidenced by improved cardiac function and reduced cardiomyocyte apoptosis and cardiac fibrosis. Furthermore, the therapeutic effect of C30 on DCM was correlated to p38MAPK inhibition and AMPK pathway activation in vivo and in vitro. In conclusion, MD2 inhibition exhibits therapeutic effects on DCM through p38MAPK inhibition and AMPK activation, which enables MD2 a promising target for DCM treatment by suppressing metaflammation and improving cardiac metabolism.

Selenium-Rich Yeast Peptide Fraction Ameliorates Imiquimod-Induced Psoriasis-like Dermatitis in Mice by Inhibiting Inflammation via MAPK and NF-κB Signaling Pathways.

Psoriasis, a chronic and immune-mediated inflammatory disease, adversely affects patients’ lives. We previously prepared selenium-rich yeast peptide fraction (SeP) from selenium-rich yeast protein hydrolysate and found that SeP could effectively alleviate ultraviolet radiation-induced skin damage in mice and inhibited H2O2-induced cytotoxicity in cultured human epidermal keratinocyte (HaCaT) cells. This study aimed to investigate whether SeP had a protective effect on imiquimod (IMQ)-induced psoriasis-like dermatitis in mice and the underlying mechanisms. Results showed that SeP significantly ameliorated the severity of skin lesion in IMQ-induced psoriasis-like mouse model. Moreover, SeP treatment significantly attenuated the expression of key inflammatory cytokines, including interleukin (IL)-23, IL-17A, and IL-17F, in the dorsal skin of mice. Mechanistically, SeP application not only inhibited the activation of JNK and p38 MAPK, but also the translocation of NF-κB into the nucleus in the dorsal skin. Furthermore, SeP treatment inhibited the levels of inflammatory cytokines and the activation of MAPK and NF-κB signaling induced by lipopolysaccharide in HaCaT cells and macrophage cell line RAW264.7. Overall, our findings showed that SeP alleviated psoriasis-like skin inflammation by inhibiting MAPK and NF-κB signaling pathways, which suggested that SeP would have a potential therapeutic effect against psoriasis.

Mycobacterial PPE36 Modulates Host Inflammation by Promoting E3 Ligase Smurf1-Mediated MyD88 Degradation

Mycobacterium tuberculosis (Mtb) PPE36, a cell-wall-associated protein, is highly specific and conserved for the Mtb complex group. Although PPE36 has been proven essential for iron utilization, little is known about it in regulating host immune responses. Here we exhibited that PPE36 was preferentially enriched in Mtb virulent strains and could efficiently inhibit host inflammatory responses and increase bacterial loads in infected macrophages and mice. In exploring the underlying mechanisms, we found that PPE36 could robustly inhibit the activation of inflammatory NF-κB and MAPK (Erk, p38, and Jnk) pathways by promoting E3 ligase Smurf1-mediated ubiquitination and proteasomal degradation of MyD88 protein. Our research revealed a previously unknown function of PPE36 on modulating host immune responses and provided some clues to the development of novel tuberculosis treatment strategies based on immune regulation.

Periostin attenuates oxygen and glucose deprivation-induced death of mouse neural stem cells via inhibition of p38 MAPK activation

Promoting neural stem cells (NSCs) survival in the harsh niche is essential to cell replacement therapy for various central nervous system diseases. As an integral component of the extracellular matrix, Periostin (POSTN) has been shown to protect various cell types from hypoxia-ischemia damage. This study aimed to investigate the neuroprotective effects of POSTN on NSCs injury induced by oxygen and glucose deprivation (OGD). Under challenge with OGD, cell viability significantly decreased in cultured mouse NSCs, and supplement POSTN rescued cell viability in a concentration-dependent manner, as shown by CCK-8. TUNEL and propidium iodide/Hoechst staining showed that POSTN pretreatment protected NSCs against OGD-induced apoptosis. Western blot assay demonstrated that POSTN pretreatment inhibited cleavage of caspase-3 and restored the balance of Bcl-2/Bax. And pretreatment with cilengitide (an inhibitor of POSTN receptors) abolished the protective effect of POSTN. Further investigation demonstrated that supplement POSTN inhibited phosphorylation of p38 in a concentration-dependent manner. Moreover, the neuroprotective effect of POSTN was hampered by anisomycin, an activator of p38. We conclude that POSTN pretreatment in cultured mouse NSCs mitigated OGD-induced cell death, and inhibition of the p38 MAPK pathway might be one of the underlying mechanisms. Our findings may provide a novel strategy for enhancing both endogenous and exogenous NSCs survival after ischemia and hypoxia injury.

Alpha 1 Antitrypsin Regulates Trophoblast Syncytialization and Inflammatory Factor Expression.

The serine protease inhibitor alpha1-antitrypsin (A1AT) may possess protective functions of impaired organs in a manner independent of its protease inhibitor activity. A1AT expression has been shown to fluctuate in patients with pregnancy-induced hypertension, which suggests that A1AT may play a role in the syncytialization of villous trophoblasts. A1AT expression was knocked down in primary trophoblasts. RNA was extracted from these cells and subjected to RNA-sequencing analysis to determine the levels of expression of markers of syncytialization and inflammation. In addition, A1AT protein was localized in trophoblastic cells in placental tissues. Knockdown of A1AT upregulated the expression of FOSL1 and markers of syncytialization, as well as cell fusion, whereas overexpression of A1AT had the opposite effects. FOSL1 overexpression stimulated syncytialization, similar to the effects of A1AT knock down. Inhibitors of p38MAPK and JNK reduce the expression of inflammatory factors, whereas a p38MAPK inhibitor suppressed FOSL1 expression. Collectively, these findings indicated A1AT may negatively regulate inflammatory responses by controlling the activation of p38MAPK and JNK, and that p38MAPK mediates trophoblast syncytialization by altering FOSL1 expression. Therefore, a dysfunction in A1AT could be responsible for abnormal placental formation and pregnancy-associated disorders.

Mechanism of Carthami Flos and Lepidii Semen drug pair in inhibition of myocardial fibrosis by improving cardiac microenvironment based on network pharmacology and animal experiment

Previously, Carthami Flos and Lepidii Semen(CF-LS) drug pair has been proved effective in inhibiting myocardial fibrosis(MF) by blunting the activity of cardiac fibroblasts. The present study explored the underlying mechanism of CF-LS in inhibiting MF by improving the cardiac microenvironment based on network pharmacology combined with experimental verification. Active compounds and potential targets of CF-LS were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), and the potential targets of MF were obtained from GeneCards, Online Mendelian Inheritance in Man(OMIM), and Pharmacogenetics and Pharmacogenomics Knowledge Base(PharmGKB). The "active component-target-MF" network was constructed and analyzed by Cytoscape 3.8.1. The protein-protein interaction(PPI) network was constructed by STRING. The Gene Ontology(GO) biological process enrichment analysis was performed by CluoGO plug-in. Kyoto Encyclopedia of Genes and Genomes(KEGG) signaling pathway enrichment analysis was performed by R 4.0.2 and Funrich. Subsequently, the inhibitory effect of CF-LS on MF was investigated based on angiotensin Ⅱ(Ang Ⅱ)-induced MF rats. RT-PCR and ELISA were used to verify the effect of CF-LS on the targets of signaling pathways related to vascular endothelial cells predicted by the network pharmacology. Thirty-one active components and 204 potential targets of CF-LS, 4 671 MF-related targets, and 174 common targets were obtained. The network analysis showed that the key targets of CF-LS against MF included RAC-alpha serine/threonine-protein kinase(AKT1), transcription factor AP-1(JUN), mitogen-activated protein kinase 1(MAPK1), cellular tumor antigen p53(TP53), transcription factor p65(RELA), and mitogen-activated protein kinase 8(MAPK8). Biological processes mainly involved regulation of blood vessel diameter, regulation of blood vessel endothelial cell migration, cell death in response to oxidative stress, etc. Advanced glycation end products(AGE)-receptor for advanced glycation end products(RAGE) signaling pathway, phosphoinositide 3-kinase(PI3 K)-serine/threonine protein kinase(AKT) signaling pathway, hypoxia-inducible factor-1(HIF-1) signaling pathway, integrin signaling pathway, transforming growth factor-β(TGF-β) signaling pathway, etc. were involved in signaling pathway enrichment. Literature retrieval confirmed that some of these signaling pathways were closely related to vascular endothelial cells, including AGE-RAGE, PI3 K-AKT, HIF-1α, p53, the transcription factor activator protein-1(AP-1), integrin, p38 MAPK, and TGF-β. Animal experiments showed that CF-LS inhibited MF induced by Ang Ⅱ in rats by suppressing the expression of RAGE, HIF-1α, integrin β6, and TGF-β1. The inhibitory effect of CF-LS on MF has the characteristics of multiple components, multiple targets, and multiple pathways. CF-LS can inhibit MF by regulating the activity of vascular endothelial cells in the cardiac microenvironment.

AGEs/RAGE Promote Osteogenic Differentiation in Rat Bone Marrow-Derived Endothelial Progenitor Cells via MAPK Signaling.

Systemic vascular impairment is the most common complication of diabetes. Advanced glycation end products (AGEs) can exacerbate diabetes-related vascular damage by affecting the intima and media through a variety of mechanisms. In the study, we demonstrated that AGEs and their membrane receptor RAGE could induce the differentiation of EPCs into osteoblasts under certain circumstances, thereby promoting accelerated atherosclerosis. Differentiation into osteoblasts was confirmed by positive staining for DiI-acetylated fluorescently labeled low-density lipoprotein and FITC-conjugated Ulex europaeus agglutinin. During differentiation, expression of receptor for AGE (RAGE) was significantly upregulated. This upregulation was attenuated by transfection with RAGE-targeting small interfering (si)RNA. siRNA-mediated knockdown of RAGE expression significantly inhibited the upregulation of AGE-induced calcification-related proteins, such as runt-related transcription factor 2 (RUNX2) and osteoprotegerin (OPG). Additional experiments showed that AGE induction of EPCs significantly induced ERK, p38MAPK, and JNK activation. The AGE-induced upregulation of osteoblast proteins (RUNX2 and OPG) was suppressed by treatment with a p38MAPK inhibitor (SB203580) or JNK inhibitor (SP600125), but not by treatment with an ERK inhibitor (PD98059), which indicated that AGE-induced osteoblast differentiation from EPCs may be mediated by p38MAPK and JNK signaling, but not by ERK signaling. These data suggested that AGEs may bind to RAGE on the EPC membrane to trigger differentiation into osteoblasts. The underlying mechanism appears to involve the p38MAPK and JNK1/2 pathways, but not the ERK1/2 pathway.

Disruption of Prostaglandin E2 Signaling in Cancer-Associated Fibroblasts Limits Mammary Carcinoma Growth but Promotes Metastasis.

The inflammatory lipid prostaglandin E2 suppresses cancer-associated fibroblast expansion and activation to limit primary mammary tumor growth while promoting metastasis.

Pharmacological Inhibition of FAK-Pyk2 Pathway Protects Against Organ Damage and Prolongs the Survival of Septic Mice.

Sepsis and septic shock are associated with high mortality and are considered one of the major public health concerns. The onset of sepsis is known as a hyper-inflammatory state that contributes to organ failure and mortality. Recent findings suggest a potential role of two non-receptor protein tyrosine kinases, namely Focal adhesion kinase (FAK) and Proline-rich tyrosine kinase 2 (Pyk2), in the inflammation associated with endometriosis, cancer, atherosclerosis and asthma. Here we investigate the role of FAK-Pyk2 in the pathogenesis of sepsis and the potential beneficial effects of the pharmacological modulation of this pathway by administering the potent reversible dual inhibitor of FAK and Pyk2, PF562271 (PF271) in a murine model of cecal ligation and puncture (CLP)-induced sepsis. Five-month-old male C57BL/6 mice underwent CLP or Sham surgery and one hour after the surgical procedure, mice were randomly assigned to receive PF271 (25 mg/kg, s.c.) or vehicle. Twenty-four hours after surgery, organs and plasma were collected for analyses. In another group of mice, survival rate was assessed every 12 h over the subsequent 5 days. Experimental sepsis led to a systemic cytokine storm resulting in the formation of excessive amounts of both pro-inflammatory cytokines (TNF-α, IL-1β, IL-17 and IL-6) and the anti-inflammatory cytokine IL-10. The systemic inflammatory response was accompanied by high plasma levels of ALT, AST (liver injury), creatinine, (renal dysfunction) and lactate, as well as a high, clinical severity score. All parameters were attenuated following PF271 administration. Experimental sepsis induced an overactivation of FAK and Pyk2 in liver and kidney, which was associated to p38 MAPK activation, leading to increased expression/activation of several pro-inflammatory markers, including the NLRP3 inflammasome complex, the adhesion molecules ICAM-1, VCAM-1 and E-selectin and the enzyme NOS-2 and myeloperoxidase. Treatment with PF271 inhibited FAK-Pyk2 activation, thus blunting the inflammatory abnormalities orchestrated by sepsis. Finally, PF271 significantly prolonged the survival of mice subjected to CLP-sepsis. Taken together, our data show for the first time that the FAK-Pyk2 pathway contributes to sepsis-induced inflammation and organ injury/dysfunction and that the pharmacological modulation of this pathway may represents a new strategy for the treatment of sepsis.

Gastrodin Pretreatment Alleviates Renal Ischemia-Reperfusion Injury

Introduction: This study aimed to investigate the possible effect of gastrodin in renal ischemia-reperfusion injury (IRI) and the mechanisms. Methods: Forty-eight male Sprague Dawley rats were randomly divided into 3 groups: sham-operated group, saline-treated IRI group, and gastrodin-treated IRI group. Gastrodin or 0.9% saline (300 mg/kg/day) was intragastrically administrated for 8 days before operation. We analyzed renal function and histological change. The malondialdehyde level, antioxidant enzymes’ activities, and markers of inflammation and apoptosis were measured. Statistical analysis was performed using 1-way analysis of variance (ANOVA) or Kruskal-Wallis ANOVA on ranks. Results: Gastrodin pretreatment improved IRI-induced renal dysfunction and histologic injury. Mechanistically, gastrodin reversed the elevation of malondialdehyde level and the reduction of antioxidant enzymes’ activities. Gastrodin also reduced the elevated myeloperoxidase activity, TNF-α and IL-1β levels, and the activation of p38 MAPK. Moreover, gastrodin-treated rats exhibited a dramatic reduction in renal tubular apoptosis, along with a decrease in caspase-3 activation and an increase in the Bcl-2/Bax ratio. Conclusion: Gastrodin pretreatment may alleviate renal IRI via the amelioration of oxidative injury, inflammatory response, and renal tubular apoptosis.

Novel imidazo[1,2-a]pyridine derivatives induce apoptosis and cell cycle arrest in non-small cell lung cancer by activating NADPH oxidase mediated oxidative stress

AimsImidazo[1,2-a]pyridine-based analogues have recently gained significant interest because of their wide spectrum of biological activities including anti-cancer potential, however the development of targeted therapeutic candidates against non-small cell lung cancer (NSCLC) is of utmost need due to its high prevalence and poor prognosis. Herein, we have aimed to synthesized novel imidazo [1,2-a] pyridine derivatives (IMPA) by coupling with 2-amino-4H-pyran to enhance bioactivity against NSCLC. Main methodsWe have designed and synthesized a series of fifteen novel imidazo [1,2-a] pyridine derivatives through molecular hybridization and studied their anti-cancer activity against in-vitro lung adenocarcinoma and 3D multicellular lung tumor spheroids. Key findingsIMPA-2, IMPA-5, IMPA-6, IMPA-8, and IMPA-12 markedly induced cytotoxicity by notably increased NADPH oxidase (NOX) activity, which results in the induction of ROS-mediated apoptosis in A549 lung cancer cells. It caused impairment of mitochondrial membrane potential by increasing pro-apoptotic BAX, and BAK1 expressions, and decreasing anti-apoptotic BCL2 expression, along with the induction of caspase-9/3 activation, however, these attributes were compromised in presence of N-acetyl-L-cysteine (NAC), a free radical scavenger. Increased ROS production by IMPAs also promotes p53 mediated cell cycle arrest through the inactivation of p38MAPK. Reduction of tumor size in IMPAs-treated 3D multicellular lung tumor spheroids gave further validation. SignificanceBeside cytotoxicity, IMPAs also inhibit lung cancer cell invasion and migration, suggesting their applicability in metastatic lung cancer. Therefore, IMPA derivatives could be used as potential anti-cancer agents in treating non-small cell lung cancer.

LPS induces pulmonary microvascular endothelial cell barrier dysfunction by upregulating ceramide production

The specific role of ceramides in pulmonary microvascular endothelial cell (PMVEC) barrier dysfunction remains unclear. In the present study, pretreatment with pan-caspase inhibitors significantly reduced LPS-induced PMVEC apoptosis and helped to stimulate PMVEC barrier reconstruction after 12 h but had no effect on PMVEC barrier dysfunction in the first 8 h. Further studies showed that imipramine, an acid sphingomyelinase (ASMase) inhibitor, significantly inhibited LPS-induced barrier dysfunction, while an siRNA targeting serine palmityl transferase subunit 1 (SPTLC1) and the pharmacological inhibitor myriocin did not inhibit early acute barrier dysfunction but significantly inhibited PMVEC apoptosis and apoptosis-dependent delayed barrier dysfunction. In addition, LPS was shown to activate RhoA by inducing transient receptor potential channel 6 (TRPC6) overexpression and calcium influx through the ASMase/ceramide pathway, and activation of RhoA further induced the cytoskeletal rearrangement of PMVECs and destruction of intercellular junctions, ultimately leading to early acute PMVEC barrier dysfunction. However, regarding apoptosis-dependent delayed barrier dysfunction, the ceramide-induced de novo synthesis pathway in paracellular cells induced the apoptosis of PMVECs, in which Txnip overexpression inhibited Trx activity and subsequently activated ASK1 in the context of LPS-induced PMVEC apoptosis, acting upstream of the ceramide-induced activation of p38 MAPK and JNK. At the same time, in rats with LPS- or exogenous C8 ceramide-induced ALI, ceramide was demonstrated to play an important role in lung injury by inducing the Txnip/TRX/ASK1/P38 and JNK pathways. Thus, the Txnip/TRX/ASK1/p38 and JNK pathways might be involved in ceramide-mediated PMVEC apoptosis in LPS-induced ALI.

Downregulation of cathepsin C alleviates endothelial cell dysfunction by suppressing p38 MAPK/NF-κB pathway in preeclampsia

ABSTRACT Endothelial cell dysfunction is an essential pathophysiological feature of preeclampsia (PE). It has been reported that cathepsin C is upregulated in the maternal vascular endothelium of PE patients. The excessive activation of p38 MAPK leads to various diseases, including PE. NF-κB pathway can promote uteroplacental dysfunction, endothelial stress and development of PE. Moreover, it has been verified that cathepsin C can activate p38 MAPK/NF-κB pathway. In the present work, hypoxia/reoxygenation (H/R) injury model of HUVECs was established to discuss the biological functions of cathepsin C in endothelial cell dysfunction and to elucidate the underlying molecular mechanism. The correlation between cathepsin C and p38 MAPK/NF-κB pathway in H/R-stimulated HUVECs as well as the effects of cathepsin C and p38 MAPK/NF-κB pathway on viability, apoptosis, invasion, in vitro angiogenesis of HUVECs and oxidative stress were assessed. The results revealed that H/R injury elevated cathepsin C expression and activated p38 MAPK/NF-κB pathway in HUVECs and cathepsin C knockdown inhibited the activity of p38 MAPK/NF-κB pathway in H/R-stimulated HUVECs. Downregulation of cathepsin C improved viability, inhibited apoptosis and enhanced invasion of H/R-stimulated HUVECs. In addition, downregulation of cathepsin C alleviated oxidative stress and induced stronger HUVEC angiogenesis in vitro. Furthermore, the protective effects of cathepsin C knockdown against endothelial cell dysfunction were reversed by p38 MAPK activator anisomycin. In other words, downregulation of cathepsin C could improve HUVEC viability and enhance anti-apoptotic capacity, anti-oxidative capability, invasive ability, as well as angiogenic potential of H/R-stimulated HUVECs by repressing p38 MAPK/NF-κB pathway.

Inhibitory Effects of 6,8-Diprenylorobol on Endometriosis Progression in Humans by Disrupting Calcium Homeostasis and Mitochondrial Function.

6,8-Diprenylorobol is a flavonoid compound extracted from Cudrania tricuspidata. It has various biological functions, such as inhibiting melanin synthesis and inducting cell death in cancerous cells. In addition, Cudrania tricuspidata is known to be effective in female diseases, and previous studies have shown anticancer effects in cervical cancer, a female reproductive disease. Outside of that, Cudrania tricuspidata has various physiological effects. However, the effect of 6,8-diprenylorobol is not well known in other benign and chronic diseases, even in endometriosis, which commonly arises in the female reproductive tract. In the present study, we determined the inhibitory effects of 6,8-diprenylorobol on the growth of endometriosis VK2/E6E7 and End1/E6E7 cells. Results indicated that 6,8-diprenylorobol suppressed cellular proliferation and increased the disruption of the cell cycle, mitochondrial membrane potential (MMP), generation of reactive oxygen species, and Ca2+ homeostasis in both endometriosis cells. However, the proliferation of normal stromal cells isolated from endometrial tissue was not altered by 6,8-diprenylorobol. The change in Ca2+ levels was estimated in fluo-4- or rhod-2-stained VK2/E6E7 and End1/E6E7 cells after the treatment of the intracellular calcium regulators 2-aminoethoxydiphenyl borate (2-APB) and ruthenium red (RUR) with 6,8-diprenylorobol. A combination of 6,8-diprenylorobol with each regulator decreased the calcium accumulation in endometriosis cells. Furthermore, Western blot analysis indicated that 6,8-diprenylorobol inactivated AKT pathways, whereas it activated P38 MAPK pathways. In addition, 6,8-diprenylorobol decreased mitochondrial respiration, leading to the reduction in ATP production in VK2/E6E7 and End1/E6E7 cells. Collectively, our results suggested that 6,8-diprenylorobol might be a potential therapeutic agent or adjuvant therapy for the management of endometriosis.

P38 Inhibition Decreases Tau Toxicity in Microglia and Improves Their Phagocytic Function

Alzheimer’s disease (AD) and other tauopathies are histopathologically characterized by tau aggregation, along with a chronic inflammatory response driven by microglia. Over the past few years, the role of microglia in AD has been studied mainly in relation to amyloid-β (Aβ) pathology. Consequently, there is a substantial knowledge gap concerning the molecular mechanisms involved in tau-mediated toxicity and neuroinflammation, thus hindering the development of therapeutic strategies. We previously demonstrated that extracellular soluble tau triggers p38 MAPK activation in microglia. Given the activation of this signaling pathway in AD and its involvement in neuroinflammation processes, here we evaluated the effect of p38 inhibition on primary microglia cultures subjected to tau treatment. Our data showed that the toxic effect driven by tau in microglia was diminished through p38 inhibition. Furthermore, p38 blockade enhanced microglia-mediated tau phagocytosis, as reflected by an increase in the number of lysosomes. In conclusion, these results contribute to our understanding of the functions of p38 in the central nervous system (CNS) beyond tau phosphorylation in neurons and provide further insights into the potential of p38 inhibition as a therapeutic strategy to halt neuroinflammation in tauopathies.

Effect of long-chain inorganic polyphosphate treated with wheat phytase on interleukin 8 signaling in HT-29 cells.

ObjectiveThis study was performed to investigate the potential effect of wheat phytase on long-chain inorganic polyphosphate (polyP)-mediated interleukin 8 (IL-8) signaling in an intestinal epithelial cell line, HT-29 cells.MethodsCell viability and the release of the pro-inflammatory cytokine IL-8 in HT-29 cells exposed to polyP1150 (average of 1,150 phosphate residues) treated with or without wheat phytase were measured by the EZ-CYTOX kit and the IL-8 ELISA kit, respectively. Also, the activation of cellular inflammatory factors NF-κB and MAPK (p38 and ERK 1/2) in HT-29 cells was investigated using ELISA kits.ResultsPolyP1150 negatively affected the viability of HT-29 cells in a dose-dependent manner. However, 100 mM polyP1150 dephosphorylated by wheat phytase increased cell viability by 1.4-fold over that of the intact substrate. Moreover, the 24 h exposure of cells to enzyme-treated 50 mM polyP1150 reduced the secretion of IL-8 and the activation of NF-κB by 9% and 19%, respectively, compared to the intact substrate. PolyP1150 (25 and 50 mM) dephosphorylated by the enzyme induced the activation of p38 MAPK via phosphorylation to 2.3 and 1.4-fold, respectively, compared to intact substrate, even though it had little effect on the expression of ERK 1/2 via phosphorylation.ConclusionWheat phytase could attenuate polyP1150-induced IL-8 release in HT-29 cells through NF-κB, independent of MAP kinases p38 and ERK. Thus, wheat phytase may alleviate inflammatory responses including hypercytokinemia caused by bacterial polyP infection in animals. Therefore, wheat phytase has the potential as an anti-inflammatory therapeutic supplement in animal husbandry.