p38α mitogen-activated protein kinase depletion and repression of signal transduction to translation machinery by miR-124 and -128 in neurons

Tolerized Microglia Protect Neurons Against Endotoxin-Induced TNF-α Production via an LBP-Dependent Intracellular p38 MAPK Signaling Pathway

The development of microglial endotoxin tolerance (ET) is a critical event in protecting neurons against excessive immune responses when microglia are administered two consecutive lipopolysaccharide (LPS) challenges. However, the intrinsic mechanisms of microglia shape ET programs and protect neurons remain unclear. This study aimed to determine whether extracellular autocrine cascades or intracellular signaling pathways are involved in ET microglia-mediated tumor necrosis factor-alpha (TNF-α) reduction and neuroprotection. Neuron-glia cultures composed of astroglia, neurons, and microglia were performed in different conditions: with or without serum or LPS-binding proteins (LBP), along with an induction approach of ET. Enzyme-linked immunosorbent assay results revealed that LPS induced TNF-α tolerance of microglia in an LBP-dependent manner. Furthermore, we determined whether the early pro-inflammatory cytokines induced by LPS might contribute to the development of microglial ET. Our data showed that the neutralization of TNF-α using an anti-TNF-α antibody had no change in the TNF-α tolerance of microglia during the ET challenge. Furthermore, pre-incubation of TNF-α, interleukin-1 beta, and prostaglandin E2 failed to induce any TNF-α tolerance in microglia after LPS treatment. Moreover, using three specific chemical inhibitors that respectively blocked the activities of the mitogen-activated protein kinases (MAPKs) namely p38, c-Jun N-terminal kinase and extracellular signal-related kinases revealed that inhibition of p38 MAPK by SB203580 disrupted the tolerated microglia-mediated TNF-α reduction and neuroprotection. In summary, our findings demonstrated that the LPS pre-treatment immediately programmed the microglial ET to prevent endotoxin-induced TNF-α production and neuronal damage through the intracellular p38 MAPK signaling pathway.

The microRNA-7322-5p/p38/Hsp19 axis modulates Chilo suppressalis cell-defences against Cry1Ca: an effective target for a stacked transgenic rice approach

Bacillus thuringiensis (Bt)-secreted crystal (Cry) toxins form oligomeric pores in host cell membranes and are a common element in generating insect-resistant transgenic crops. Although Cry toxin function has been well documented, cellular defences against pore-formation have not been as well developed. Elucidation of the processes underlying this defence, however, could contribute to the development of enhanced Bt crops. Here, we demonstrate that Cry1Ca-mediated downregulation of microRNA-7322-5p (miR-7322-5p), which binds to the 3' untranslated region of p38, negatively regulates the susceptibility of Chilo suppressalis to Cry1Ca. Moreover, Cry1Ca exposure enhanced phosphorylation of Hsp19, and hsp19 downregulation increased susceptibility to Cry1Ca. Further, Hsp19 phosphorylation occurs downstream of p38, and pull-down assays confirmed the interactions between Hsp19 and Cry1Ca, suggesting that activation of Hsp19 by the miR-7322-5p/p38/Hsp19 pathway promotes Cry1Ca sequestration. To assess the efficacy of targeting this pathway in planta, double-stranded RNA (dsRNA) targeting C. suppressalis p38 (dsp38) was introduced into a previously generated cry1Ca-expressing rice line (1CH1-2) to yield a single-copy cry1Ca/dsp38 rice line (p38-rice). Feeding on this rice line triggered a significant reduction in C. suppressalis p38 expression and the line was more resistant to C. suppressalis than 1CH1-2 in both short term (7-day) and continuous feeding bioassays as well as field trials. These findings provide new insights into invertebrate epithelium cellular defences and demonstrate a potential new pyramiding strategy for Bt crops.

Exploring the impact of miR-128 in inflammatory diseases: A comprehensive study on autoimmune diseases

microRNAs (miRNAs) play a crucial role in various biological processes, including immune system regulation, such as cell proliferation, tolerance (central and peripheral), and T helper cell development. Dysregulation of miRNA expression and activity can disrupt immune responses and increase susceptibility to neuroimmune disorders. Conversely, miRNAs have been shown to have a protective role in modulating immune responses and preventing autoimmunity. Specifically, reducing the expression of miRNA-128 (miR-128) in an Alzheimer's disease (AD) mouse model has been found to improve cognitive deficits and reduce neuropathology. This comprehensive review focuses on the significance of miR-128 in the pathogenesis of neuroautoimmune disorders, including multiple sclerosis (MS), AD, Parkinson's disease (PD), Huntington's disease (HD), epilepsy, as well as other immune-mediated diseases such as inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). Additionally, we present compelling evidence supporting the potential use of miR-128 as a diagnostic or therapeutic biomarker for neuroimmune disorders. Collectively, the available literature suggests that targeting miR-128 could be a promising strategy to alleviate the behavioral symptoms associated with neuroimmune diseases. Furthermore, further research in this area may uncover new insights into the molecular mechanisms underlying these disorders and potentially lead to the development of novel therapeutic approaches.

Preclinical and randomized clinical evaluation of the p38α kinase inhibitor neflamapimod for basal forebrain cholinergic degeneration

The endosome-associated GTPase Rab5 is a central player in the molecular mechanisms leading to degeneration of basal forebrain cholinergic neurons (BFCN), a long-standing target for drug development. As p38α is a Rab5 activator, we hypothesized that inhibition of this kinase holds potential as an approach to treat diseases associated with BFCN loss. Herein, we report that neflamapimod (oral small molecule p38α inhibitor) reduces Rab5 activity, reverses endosomal pathology, and restores the numbers and morphology of BFCNs in a mouse model that develops BFCN degeneration. We also report on the results of an exploratory (hypothesis-generating) phase 2a randomized double-blind 16-week placebo-controlled clinical trial (Clinical trial registration: NCT04001517/EudraCT #2019-001566-15) of neflamapimod in mild-to-moderate dementia with Lewy bodies (DLB), a disease in which BFCN degeneration is an important driver of disease expression. A total of 91 participants, all receiving background cholinesterase inhibitor therapy, were randomized 1:1 between neflamapimod 40 mg or matching placebo capsules (taken orally twice-daily if weight <80 kg or thrice-daily if weight >80 kg). Neflamapimod does not show an effect in the clinical study on the primary endpoint, a cognitive-test battery. On two secondary endpoints, a measure of functional mobility and a dementia rating-scale, improvements were seen that are consistent with an effect on BFCN function. Neflamapimod treatment is well-tolerated with no study drug associated treatment discontinuations. The combined preclinical and clinical observations inform on the validity of the Rab5-based pathogenic model of cholinergic degeneration and provide a foundation for confirmatory (hypothesis-testing) clinical evaluation of neflamapimod in DLB.

Microarray meta-analysis reveals IL6 and p38β/MAPK11 as potential targets of hsa-miR-124 in endothelial progenitor cells: Implications for stent re-endothelization in diabetic patients

Circulating endothelial progenitor cells (EPCs) play an important role in the repair processes of damaged vessels, favoring re-endothelization of stented vessels to minimize restenosis. EPCs number and function is diminished in patients with type 2 diabetes, a known risk factor for restenosis. Considering the impact of EPCs in vascular injury repair, we conducted a meta-analysis of microarray to assess the transcriptomic profile and determine target genes during the differentiation process of EPCs into mature ECs. Five microarray datasets, including 13 EPC and 12 EC samples were analyzed, using the online tool ExpressAnalyst. Differentially expressed genes (DEGs) analysis was done by Limma method, with an | log2FC| &gt; 1 and FDR &lt; 0.05. Combined p-value by Fisher exact method was computed for the intersection of datasets. There were 3,267 DEGs, 1,539 up-regulated and 1,728 down-regulated in EPCs, with 407 common DEGs in at least four datasets. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed enrichment for terms related to “AGE-RAGE signaling pathway in diabetic complications.” Intersection of common DEGs, KEGG pathways genes and genes in protein-protein interaction network (PPI) identified four key genes, two up-regulated (IL1B and STAT5A) and two down-regulated (IL6 and MAPK11). MicroRNA enrichment analysis of common DEGs depicted five hub microRNA targeting 175 DEGs, including STAT5A, IL6 and MAPK11, with hsa-miR-124 as common regulator. This group of genes and microRNAs could serve as biomarkers of EPCs differentiation during coronary stenting as well as potential therapeutic targets to improve stent re-endothelization, especially in diabetic patients.

MicroRNA-124 Promotes Singapore Grouper Iridovirus Replication and Negatively Regulates Innate Immune Response

Viral infections seriously affect the health of organisms including humans. Now, more and more researchers believe that microRNAs (miRNAs), one of the members of the non-coding RNA family, play significant roles in cell biological function, disease occurrence, and immunotherapy. However, the roles of miRNAs in virus infection (entry and replication) and cellular immune response remain poorly understood, especially in low vertebrate fish. In this study, based on the established virus-cell infection model, Singapore grouper iridovirus (SGIV)-infected cells were used to explore the roles of miR-124 of Epinephelus coioides, an economically mariculture fish in southern China and Southeast Asia, in viral infection and host immune responses. The expression level of E. coioides miR-124 was significantly upregulated after SGIV infection; miR-124 cannot significantly affect the entry of SGIV, but the upregulated miR-124 could significantly promote the SGIV-induced cytopathic effects (CPEs), the viral titer, and the expressions of viral genes. The target genes of miR-124 were JNK3/p38α mitogen-activated protein kinase (MAPK). Overexpression of miR-124 could dramatically inhibit the activation of NF-κB/activating protein-1 (AP-1), the transcription of proinflammatory factors, caspase-9/3, and the cell apoptosis. And opposite results happen when the expression of miR-124 was inhibited. The results suggest that E. coioides miR-124 could promote viral replication and negatively regulate host immune response by targeting JNK3/p38α MAPK, which furthers our understanding of virus and host immune interactions.

MicroRNA-124 acts as a positive regulator of IFN-β signaling in the lipopolysaccharide-stimulated human microglial cells

miR-124 is ubiquitously expressed in the nervous tissue and acts as a negative regulator of neuroinflammation. In the present study, we analyzed the possible role of miR-124 in response to LPS in the human microglial cell line. Our data revealed that the miR-124 anti-inflammatory effect is based not only on the suppression of MyD88 - NFκB pathway and downregulation of pro-inflammatory cytokines IL-1β and IL-6 but also on the enhancement of TRAM-TRIF signaling and increased IFN-β expression. Furthermore, the NFκB reporter assay demonstrated that specific miR-124 - induced NFκB activity changes could be detected only using NFκB reporter promoters lacking ATF/CREB binding site.

Statistical Analysis for Identifying Differentially MicroRNA in Serum Exosomes of Lead Workers

Exosomes can transmit central nervous system (CNS) information to the peripheral circulatory system through the brain barrier, and exosomes in the blood can also enter the central nervous system likewise. The components of exosomal contents play a pivotal role in cell signal communication, and thus, the transmission of exosomal content components is considered as a newly discovered method of long-distance communication between cells. The current is aimed to explore the changes of the exosomal microRNA group in the serum of lead-exposed workers, which might be involved in the lead-induced neuroinflammation, especially the activation of microglia and the release of inflammatory factors. We proposed a method combining statistical analysis and experiment according to the different expression of exosomal microRNA. Firstly, we divided workers into two groups, lead-exposed group and control group, and then questionnaires were used to obtain their basic information, and medical testing methods were used to obtain their serum exosomes. Secondly, principal component analysis was used to construct a comprehensive index of neurobehavioral function. Furthermore, volcano map and heatmap were used to display the differential gene distribution and correlation analysis of expression levels, respectively. Finally, two software applications, TargetScan and miRanda, were used to predict the target genes of the significantly different microRNAs, respectively, and the target genes predicted by the two software applications are screened according to the scoring standards of each software. Our results showed that 73 microRNAs were changed in the serum exosomes of lead-exposed worker, among which 48 microRNAs are upregulated and 25 microRNAs are downregulated. Moreover, the miR-124 and miR-506 were identified, and they might be involved in the process of lead-induced neuroinflammation.

Functions of p38 MAP Kinases in the Central Nervous System

Mitogen-activated protein (MAP) kinases are a central component in signaling networks in a multitude of mammalian cell types. This review covers recent advances on specific functions of p38 MAP kinases in cells of the central nervous system. Unique and specific functions of the four mammalian p38 kinases are found in all major cell types in the brain. Mechanisms of p38 activation and downstream phosphorylation substrates in these different contexts are outlined and how they contribute to functions of p38 in physiological and under disease conditions. Results in different model organisms demonstrated that p38 kinases are involved in cognitive functions, including functions related to anxiety, addiction behavior, neurotoxicity, neurodegeneration, and decision making. Finally, the role of p38 kinases in psychiatric and neurological conditions and the current progress on therapeutic inhibitors targeting p38 kinases are covered and implicate p38 kinases in a multitude of CNS-related physiological and disease states.

Exosomal miRNAs in central nervous system diseases: biomarkers, pathological mediators, protective factors and therapeutic agents

Exosomes are small bilipid layer-enclosed extracellular vesicles that can be found in tissues and biological fluids. As a key cell-to-cell and distant communication mediator, exosomes are involved in various central nervous system (CNS) diseases, potentially through transferring their contents such as proteins, lipids and nucleic acids to the target cells. Exosomal miRNAs, which are small non-coding RNAs in the exosomes, are known to be more stable than free miRNAs and therefore have lasting effects on disease-related gene expressions. There are distinct profiles of exosomal miRNAs in different types of CNS diseases even before the onset of irreversible neurological damages, indicating that exosomal miRNAs within tissues and biological fluids could serve as promising biomarkers. Emerging evidence has also demonstrated the pathological effects of several exosomal miRNAs in CNS diseases via specific modulation of disease-related factors. Moreover, exosomes carry therapeutically beneficial miRNAs across the blood-brain-barrier, which can be exploited as a powerful drug delivery tool to help alleviating multiple CNS diseases. In this review, we summarize the recent progress made in understanding the biological roles of exosomal miRNAs as potential diagnostic biomarkers, pathological regulators, and therapeutic targets/drugs for CNS diseases. A comprehensive discussion of the main concerns and challenges for the applications of exosomal miRNAs in the clinical setting is also provided.

MicroRNA-124 regulates the expression of p62/p38 and promotes autophagy in the inflammatory pathogenesis of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and nonmotor symptoms due to the selective loss of midbrain dopaminergic neurons. The evidence for a chronic inflammatory reaction mediated by microglial cells in the brain is particularly strong in PD. In our previous study, we have shown that brain-specific microRNA-124 (miR-124) is significantly down-regulated in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD and that it can also inhibit neuroinflammation during the development of PD. However, further investigation is required to understand whether the abnormal expression of miR-124 regulates microglial activation. In this study, we found that the expression of sequestosome 1 (p62) and phospho-p38 mitogen-activated protein kinases (p-p38) showed a significant increase in LPS-treated immortalized murine microglial cell line BV2 cells in an MPTP-induced mouse model of PD. Knockdown of p62 could suppress the secretion of proinflammatory cytokines and p-p38 of microglia. Besides, inhibition of p38 suppressed the secretion of proinflammatory cytokines and promoted autophagy in BV2 cells. Moreover, our study is the first to identify a unique role of miR-124 in mediating the microglial inflammatory response by targeting p62 and p38 in PD. In the microglial culture supernatant transfer model, the knockdown of p62 in BV2 cells prevented apoptosis and death of human neuroblastoma cell lines SH-SY5Y (SH-SY5Y) cells following microglia activation. In addition, the exogenous delivery of miR-124 could suppress p62 and p-p38 expression and could also attenuate the activation of microglia in the substantia nigra par compacta of MPTP-treated mice. Taken together, our data suggest that miR-124 could inhibit neuroinflammation during the development of PD by targeting p62, p38, and autophagy, indicating that miR-124 could be a potential therapeutic target for regulating the inflammatory response in PD.-Yao, L., Zhu, Z., Wu, J., Zhang, Y., Zhang, H., Sun, X., Qian, C., Wang, B., Xie, L., Zhang, S., Lu, G. MicroRNA-124 regulates the expression of p62/p38 and promotes autophagy in the inflammatory pathogenesis of Parkinson's disease.

Vascular smooth muscle-MAPK14 is required for neointimal hyperplasia by suppressing VSMC differentiation and inducing proliferation and inflammation

Injury-induced stenosis is a serious vascular complication. We previously reported that p38α (MAPK14), a redox-regulated p38MAPK family member was a negative regulator of the VSMC contractile phenotype in vitro. Here we evaluated the function of VSMC-MAPK14 in vivo in injury-induced neointima hyperplasia and the underlying mechanism using an inducible SMC-MAPK14 knockout mouse line (iSMC-MAPK14^-/-). We show that MAPK14 expression and activity were induced in VSMCs after carotid artery ligation injury in mice and ex vivo cultured human saphenous veins. While the vasculature from iSMC-MAPK14^-/- mice was indistinguishable from wildtype littermate controls at baseline, these mice exhibited reduced neointima formation following carotid artery ligation injury. Concomitantly, there was an increased VSMC contractile protein expression in the injured vessels and a decrease in proliferating cells. Blockade of MAPK14 through a selective inhibitor suppressed, while activation of MAPK14 by forced expression of an upstream MAPK14 kinase promoted VSMC proliferation in cultured VSMCs. Genome wide RNA array combined with VSMC lineage tracing studies uncovered that vascular injury evoked robust inflammatory responses including the activation of proinflammatory gene expression and accumulation of CD45 positive inflammatory cells, which were attenuated in iSMC-MAPK14^-/- mice. Using multiple pharmacological and molecular approaches to manipulate MAPK14 pathway, we further confirmed the critical role of MAPK14 in activating proinflammatory gene expression in cultured VSMCs, which occurs in a p65/NFkB-dependent pathway. Finally, we found that NOX4 contributes to MAPK14 suppression of the VSMC contractile phenotype. Our results revealed that VSMC-MAPK14 is required for injury-induced neointima formation, likely through suppressing VSMC differentiation and promoting VSMC proliferation and inflammation. Our study will provide mechanistic insights into therapeutic strategies for mitigation of vascular stenosis.

MicroRNA-128 knockout inhibits the development of Alzheimer's disease by targeting PPARγ in mouse models

Alzheimer's disease (AD) is a great threat for the health and life of elderly people. MicroRNA-128 (miR-128) has been reported to be abnormally expressed in the brain of AD patients and associated with the pathogenesis of AD. Our study aimed to have a deep insight into the roles and molecular basis of miR-128 in the development and progression of AD. The cognitive ability and exploratory behaviors were assessed by morris water maze and open-field tests, respectively. The concentrations of amyloid-β (Aβ) 40, Aβ 42, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-10 and activity of β-secretase and α-secretase were determined by corresponding ELISA commercial kits. RT-qPCR assay was performed to detect miR-128 level and the mRNA expression of peroxisome proliferator-activated receptor gamma (PPARγ), ionized calcium-binding adaptor molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP). Western blot assay was conducted to determine protein expression of PPARγ, amyloid precursor protein (APP), β-APP cleaving enzyme (BACE1), sAPPα and sAPPβ. The effect of miR-128 and PPARγ on amyloid plaque formation was assessed by immunohistochemistry assay. PPARγ mean optical density was determined by immunofluorescence assay. The interaction between miR-128 and PPARγ were validated by bioinformatics analysis and luciferase reporter assay. We found AD mice showed AD-like performance and an increased cerebral cortex Aβ production. MiR-128 expression was upregulated and PPARγ expression was downregulated in cerebral cortex of AD mice. Moreover, PPARγ was a target of miR-128. Additionally, miR-128 knockout or PPARγ upregulation inhibited AD-like performances, amyloid plaque formation, Aβ generation, APP amyloidogenic processing and inflammatory responses in AD mice, while these effects of miR-128 knockout were abrogated by PPARγ inhibitor. The results indicated MiR-128 knockout weakened AD-like performances, and reduced Aβ production and inflammatory responses by targeting PPARγ in AD mice.

How to reprogram microglia toward beneficial functions

Microglia, brain cells of nonneural origin, orchestrate the inflammatory response to diverse insults, including hypoxia/ischemia or maternal/fetal infection in the perinatal brain. Experimental studies have demonstrated the capacity of microglia to recognize pathogens or damaged cells activating a cytotoxic response that can exacerbate brain damage. However, microglia display an enormous plasticity in their responses to injury and may also promote resolution stages of inflammation and tissue regeneration. Despite the critical role of microglia in brain pathologies, the cellular mechanisms that govern the diverse phenotypes of microglia are just beginning to be defined. Here we review emerging strategies to drive microglia toward beneficial functions, selectively reporting the studies which provide insights into molecular mechanisms underlying the phenotypic switch. A variety of approaches have been proposed which rely on microglia treatment with pharmacological agents, cytokines, lipid messengers, or microRNAs, as well on nutritional approaches or therapies with immunomodulatory cells. Analysis of the molecular mechanisms relevant for microglia reprogramming toward pro‐regenerative functions points to a central role of energy metabolism in shaping microglial functions. Manipulation of metabolic pathways may thus provide new therapeutic opportunities to prevent the deleterious effects of inflammatory microglia and to control excessive inflammation in brain disorders.

Stress-Activated Protein Kinases in Spinal Cord Injury: Focus on Roles of p38

Spinal cord injury (SCI) consists of three phases-acute, secondary, and chronic damages-and limiting the development of secondary damage possibly improves functional recovery after SCI. A major component of the secondary phase of SCI is regarded as inflammation-triggered events: induction of cytokines, edema, microglial activation, apoptosis of cells including oligodendrocytes and neurons, demyelination, formation of the astrocytic scar, and so on. Two major stress-activated protein kinases (SAPKs)-c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK)-are activated in various types of cells in response to cellular stresses such as apoptotic stimuli and inflammatory waves. In animal models of SCI, inhibition of either JNK or p38 has been shown to promote neuroprotection-associated functional recovery. Here, we provide an overview on the roles of SAPKs in SCI and, in particular, the pathological role of p38 will be discussed as a promising target for therapeutic intervention in SCI.

An exploratory clinical study of p38α kinase inhibition in Alzheimer's disease

Objective

The aim of this study was to preliminarily evaluate an oral small molecule p38α kinase inhibitor in patients with early Alzheimer's disease (AD) for the effects on brain amyloid plaque load and episodic memory function, and to establish pharmacokinetic-pharmacodynamics correlations if any effects identified on these parameters.

Methods

Sixteen patients with early AD received a highly selective p38α inhibitor (neflamapimod) for 84 days (12 weeks). To obtain a broad range of plasma drug exposures, subjects randomized to receive either 40 mg (n = 9) or 125 mg (n = 7) twice daily. Dynamic, ¹¹C-PiB positron emission scans were performed at baseline and at Day 84 and quantitatively analyzed by reference parametric mapping. Episodic memory assessed as Wechsler Memory Scale (WMS) immediate and delayed recall composites.

Result

In the ¹¹C-PiB analyses there were no main group level effects, though in the prespecified responder analysis (>7% reduction in ¹¹C-PiB signal) there were three responders in the 40 mg, and one in the 125 mg group. There were statistically significant increases from baseline in mean WMS immediate recall score and WMS delayed recall at both day 28 (P = 0.03 and P = 0.001) and day 84 (P = 0.001 and P < 0.001). Individual subject plasma drug concentration profiles were significantly positively correlated with the change in combined WMS immediate and delayed recall (P < 0.0001, r² = 0.70). Within-subject effect size was 0.59 for immediate recall and 0.67 for delayed recall.

Interpretation

Selective p38α inhibition in patients with early AD may improve episodic memory and potentially impact β-amyloid production. These preliminary clinical findings support conduct of a longer duration placebo-controlled study, particularly to confirm the effects on episodic memory function.

miR-128 Regulates Genes Associated with Inflammation and Fibrosis of Rat Kidney Cells In Vitro

microRNAs (miRNAs) regulate diverse cellular functions and signaling pathways via inhibiting the expression of their target genes. Given that miR-128 mediates mitogen-activated protein kinase signaling and production of reactive oxygen species and pro-inflammatory chemokines in various types of cells and tissues, and that miR-128 is differentially expressed in aged and diseased kidneys, we hypothesized that miR-128 may play key roles in kidney inflammation. Hence, in this study, we evaluated the biological effects of miR-128 in normal rat kidney (NRK) cells in vitro. Our results revealed that overexpression of miR-128 enhanced expression of genes associated with inflammation, pro-inflammatory cytokines and fibrosis in NRK cells. The recent reports showing that expression of miR-128 is increased in liver and lung fibrosis, together with the findings in this study, suggest that miR-128 may be a pro-fibrotic miRNA that regulates fibrosis in various tissues. Anat Rec, 301:913-921, 2018. © 2017 Wiley Periodicals, Inc.

p38α regulates cytokine-induced IFNγ secretion via the Mnk1/eIF4E pathway in Th1 cells

The p38 mitogen-activated protein kinase (MAPK) pathway is involved in the regulation of immune and inflammatory processes. We used p38α-conditional, p38β-deficient and p38α/β double-null mouse models to address the role of these two p38 MAPK in CD4⁺ T cells, and found that p38α deficiency causes these cells to hyperproliferate. Our studies indicate that both p38α and p38β are dispensable for T helper cell type 1 (Th1) differentiation but, by controlling interferon (IFN)γ and tumor necrosis factor (TNF)α production, are critical for normal Th1 effector function. We found that both p38α and p38β modulate T-cell receptor-induced IFNγ and TNFα production, whereas only p38α regulates cytokine-induced IFNγ production. The lack of p38α and p38β did not affect transcription and mRNA stability of Ifng. However, the absence of p38α in Th1 cells resulted in a decreased MNK1 phosphorylation after cytokine activation, and MNK1 inhibition blocked IFNγ production. Our results indicate that p38α regulates IFNγ secretion through the activation of the MNK1/eIF4E pathway of translation initiation and identify specific functions for p38α and p38β in T-cell proliferation.

miR-128 enhances dendritic cell-mediated anti-tumor immunity via targeting of p38

MiRNA (miR)-128, which is a well‑recognized inhibitor of tumor growth, is involved in the anti-tumor function of dendritic cells (DCs). However, the association between miR‑128 and the DC‑mediated anti‑tumor immunity remains to be elucidated. Murine B16 melanoma cells and C57BL/6 male mice were used to obtain marrow‑derived DCs. DCs were treated with B16 cell suspension. miR‑128 mimic, miR‑128 inhibitor, p38 inhibitor or negative control oligonucleotides were transfected into DCs. After transfection, mRNA and protein expression of p38 in DCs was detected via reverse transcription‑quantitative polymerase chain reaction and western blotting. The present study demonstrated that the miR‑128 abundance in DCs was significantly attenuated by B16 (a melanoma cell line) stimulation and the protein expression level of p38 was increased. Additionally, miR‑128 inhibited the protein expression of p38 in DCs in a dose‑dependent manner, however no significant effect on the p38 mRNA level was observed. Furthermore, miR‑128 mimic or p38 inhibitor decreased the mRNA expression and secretion of interleukin (IL)‑6 and IL‑10 cytokines and increased the level of IL‑12 in DCs, whereas an miR‑128 inhibitor exhibited the opposite effects. These findings suggested that miR‑128 regulated the immune response of DCs via p38‑downstream cytokines. Furthermore, the tumor growth rate, size and weight were markedly decreased and the survival time prolonged, following injection of DCs harboring miR‑128 mimic or p38 inhibitor in C57BL/6 mice bearing B16 melanoma. The results therefore suggest that miR‑128 enhances the anti‑tumor immunity response of DCs via targeting of the p38 mitogen activated protein kinase signaling pathway.

The p38 pathway, a major pleiotropic cascade that transduces stress and metastatic signals in endothelial cells

By gating the traffic of molecules and cells across the vessel wall, endothelial cells play a central role in regulating cardiovascular functions and systemic homeostasis and in modulating pathophysiological processes such as inflammation and immunity. Accordingly, the loss of endothelial cell integrity is associated with pathological disorders that include atherosclerosis and cancer. The p38 mitogen-activated protein kinase (MAPK) cascades are major signaling pathways that regulate several functions of endothelial cells in response to exogenous and endogenous stimuli including growth factors, stress and cytokines. The p38 MAPK family contains four isoforms p38α, p38β, p38γ and p38δ that are encoded by four different genes. They are all widely expressed although to different levels in almost all human tissues. p38α/MAPK14, that is ubiquitously expressed is the prototype member of the family and is referred here as p38. It regulates the production of inflammatory mediators, and controls cell proliferation, differentiation, migration and survival. Its activation in endothelial cells leads to actin remodeling, angiogenesis, DNA damage response and thereby has major impact on cardiovascular homeostasis, and on cancer progression. In this manuscript, we review the biology of p38 in regulating endothelial functions especially in response to oxidative stress and during the metastatic process.

Differential effects of p38 MAP kinase inhibitors SB203580 and SB202190 on growth and migration of human MDA-MB-231 cancer cell line

p38 mitogen-activated protein kinase (MAPK) belongs to the MAPK superfamily, phosphorylating serine and/or threonine residues of the target proteins. The activation of p38 MAPK leads to cell growth, differentiation, inflammation, survival or apoptosis. In this study, we tested the effect of two highly specific and potent inhibitors of p38 MAPK (namely, SB203580 and SB202190) on human breast cancer cell line MDA-MB-231 to elucidate the controversial role of p38 MAPK on cell proliferation and/or cell migration/metastasis further. It was determined that the IC₅₀ value of SB203580 was 85.1 µM, while that of SB202190 was 46.6 µM, suggesting that SB202190 is slightly more effective than SB203580. To verify the effect of each inhibitor on cell proliferation and cytotoxicity, the cells were treated with various doses of SB203580 and SB202190 and examined using iCELLigence system. No significant effect of 1 and 5 µM of both inhibitors were seen on cell proliferation as compared to the DMSO-treated control cells for up to 96 h. On the other hand, both SB203580 and SB202190 significantly prevented cell proliferation at a concentration of 50 µM. SB202190 was again more effective than SB203580. Afterwards, we tested the effect of each inhibitor on cell migration using wound assay. Both SB203580 and SB202190 significantly reduced cell migration in a time-dependent manner at a concentration of 50 µM. However, interestingly it was observed that a low and noncytotoxic dose of 5 µM of SB203580 and SB202190 also did cause significant cell migration inhibition at 48 h of the treatment, corroborating the fact that p38 MAPK pathway has a critical role in cell migration/metastasis. Then, we tested whether each p38 MAPK inhibitor has any effect on cell adhesion during a treatment period of 3 h using iCELLigence system. A concentration of only 50 µM of SB202190 reduced cell adhesion for about 1.5 h (p < 0.001); after that period of time, cell adhesion in 50 µM SB202190-treated cells returned to the level of the control cells. To determine the mechanism of growth and cell migration inhibitory effects of p38 MAPK inhibitors, the activation/inactivation of various proteins and enzymes was subsequently analyzed by PathScan^® Intracellular Signaling Array kit. The ERK1/2 phosphorylation level was not modified by low concentrations (1 or 5 µM) of SB202190 and SB203580; while a high concentration (50 µM) of both inhibitors caused significant reductions in the ERK1/2 phosphorylation. In addition, it was determined that both p38 MAPK inhibitors caused significant increases on the Ser15 phosphorylation of mutant p53 in MDA-MB-231 under these experimental conditions; while SB202190 was more potent than SB203580.

Broad-Spectrum Inhibition of Respiratory Virus Infection by MicroRNA Mimics Targeting p38 MAPK Signaling

The majority of antiviral therapeutics target conserved viral proteins, however, this approach confers selective pressure on the virus and increases the probability of antiviral drug resistance. An alternative therapeutic strategy is to target the host-encoded factors that are required for virus infection, thus minimizing the opportunity for viral mutations that escape drug activity. MicroRNAs (miRNAs) are small noncoding RNAs that play diverse roles in normal and disease biology, and they generally operate through the post-transcriptional regulation of mRNA targets. We have previously identified cellular miRNAs that have antiviral activity against a broad range of herpesvirus infections, and here we extend the antiviral profile of a number of these miRNAs against influenza and respiratory syncytial virus. From these screening experiments, we identified broad-spectrum antiviral miRNAs that caused >75% viral suppression in all strains tested, and we examined their mechanism of action using reverse-phase protein array analysis. Targets of lead candidates, miR-124, miR-24, and miR-744, were identified within the p38 mitogen-activated protein kinase (MAPK) signaling pathway, and this work identified MAPK-activated protein kinase 2 as a broad-spectrum antiviral target required for both influenza and respiratory syncytial virus (RSV) infection.

Targeting neuronal MAPK14/p38α activity to modulate autophagy in the Alzheimer disease brain

Dysregulated autophagic-lysosomal degradation of proteins has been linked to the most common genetic defect in familial Alzheimer disease, and has been correlated with disease progression in both human disease and in animal models. Recently, it was demonstrated that the expression of MAPK14/p38α protein is upregulated in the brain of APP-PS1 transgenic Alzheimer mouse and further that genetic deficiency of Mapk14 in the APP-PS1 mouse stimulates macroautophagy/autophagy, which then leads to reduced amyloid pathology via increasing autophagic-lysosomal degradation of BACE1. The findings resolve at least in the context of the APP-PS1 mouse, prior conflicting in vitro observations that have implicated MAPK14 in autophagic processes, and indicate that inhibition of MAPK14 enzyme activity has potential as a therapeutic approach to mitigate a critical physiological defect within neurons of the Alzheimer disease brain. Moreover, the findings suggest that biomarkers of BACE1 activity could be utilized to evaluate the effects of MAPK14 inhibition and other autophagy-inducing therapeutic approaches in human clinical studies, thereby potentially facilitating the clinical development of such agents.

Downregulated expression of miRNA-149 promotes apoptosis in side population cells sorted from the TSU prostate cancer cell line

The objective of the present study was to identify prostate cancer stem cells and determine the effects of modulating specific miRNAs on prostate CSC proliferation and apoptosis. We applied flow cytometry sorting of side population cells to cultures of prostate cancer cell lines (TSU, DU145, PC-3 and LNCaP). The proportion of SP cells in the TSU line was 1.60±0.40% (mean ± SD), while that of the DU145, PC-3 and LNCaP lines was 0.60±0.05, 0.80±0.05 and 0.60±0.20%, respectively. Because the proportion of SP cells derived from TSU cells is greater, these cells were selected to sort side population cells and non-side population cells. The stem-like properties of SP cells had been identified by in vivo and in vitro experiments, and the related study was published. RNA was extracted from the SP cells and non-SP cells and analyzed using miRNA microarray technology. Fifty-three miRNAs with significant differences in their expression were detected in total. Furthermore, 20 of these miRNAs were validated by qPCR. We found that hsa-miR‑149 expression in SP cells and non-SP cells was significantly different; hsa-miR-149 was significantly upregulated in SP cells. By constructing a vector for lentiviral infection, we found that the downregulation of hsa-miR-149 leads to a reduction in proliferation, an increase in apoptosis, and a significant reduction in the colony formation potential, thus, inhibiting tumor growth in vivo of SP cells from the TSU cell line. The present study will provide new avenues toward understanding the function of prostate cancer stem cells (PCSCs) in tumorigenicity and metastasis.

Inhibition of Mitogen-activated Protein Kinase (MAPK)-interacting Kinase (MNK) Preferentially Affects Translation of mRNAs Containing Both a 5'-Terminal Cap and Hairpin

The MAPK-interacting kinases 1 and 2 (MNK1 and MNK2) are activated by extracellular signal-regulated kinases 1 and 2 (ERK1/2) or p38 in response to cellular stress and extracellular stimuli that include growth factors, cytokines, and hormones. Modulation of MNK activity affects translation of mRNAs involved in the cell cycle, cancer progression, and cell survival. However, the mechanism by which MNK selectively affects translation of these mRNAs is not understood. MNK binds eukaryotic translation initiation factor 4G (eIF4G) and phosphorylates the cap-binding protein eIF4E. Using a cell-free translation system from rabbit reticulocytes programmed with mRNAs containing different 5'-ends, we show that an MNK inhibitor, CGP57380, affects translation of only those mRNAs that contain both a cap and a hairpin in the 5'-UTR. Similarly, a C-terminal fragment of human eIF4G-1, eIF4G(1357-1600), which prevents binding of MNK to intact eIF4G, reduces eIF4E phosphorylation and inhibits translation of only capped and hairpin-containing mRNAs. Analysis of proteins bound to m(7)GTP-Sepharose reveals that both CGP and eIF4G(1357-1600) decrease binding of eIF4E to eIF4G. These data suggest that MNK stimulates translation only of mRNAs containing both a cap and 5'-terminal RNA duplex via eIF4E phosphorylation, thereby enhancing the coupled cap-binding and RNA-unwinding activities of eIF4F.

[Advances of lentiviral vectors]

Lentiviral vectors are currently very effective tools in molecular and cell experiment. Lentiviral vector, a kind of retroviral vectors, has a number of unique advantages in target gene transferation, for example, the ability of transfection to the dividing or nondividing cells, its high efficiency of transfection and a capacity of large target gene fragments. This paper describes the sources of lentiviral vectors, molecular characteristics, research progress, etc.

Osmostress-induced gene expression--a model to understand how stress-activated protein kinases (SAPKs) regulate transcription

Adaptation is essential for maximizing cell survival and for cell fitness in response to sudden changes in the environment. Several aspects of cell physiology change during adaptation. Major changes in gene expression are associated with cell exposure to environmental changes, and several aspects of mRNA biogenesis appear to be targeted by signaling pathways upon stress. Exhaustive reviews have been written regarding adaptation to stress and regulation of gene expression. In this review, using osmostress in yeast as a prototypical case study, we highlight those aspects of regulation of gene induction that are general to various environmental stresses as well as mechanistic aspects that are potentially conserved from yeast to mammals.

An updated role of microRNA-124 in central nervous system disorders: a review

MicroRNA-124 (miR-124) is the most abundant miRNA in the brain. Biogenesis of miR-124 displays specific temporal and spatial profiles in various cell and tissue types and affects a broad spectrum of biological functions in the central nervous system (CNS). Recently, the link between dysregulation of miR-124 and CNS disorders, such as neurodegeneration, CNS stress, neuroimmune disorders, stroke, and brain tumors, has become evident. Here, we provide an overview of the specific molecular function of miR-124 in the CNS and a revealing insight for the therapeutic potential of miR-124 in the treatment of human CNS diseases.

MicroRNA-124 expression counteracts pro-survival stress responses in glioblastoma

Glioblastomas are aggressive adult brain tumors, characterized by inadequately organized vasculature and consequent nutrient and oxygen (O2)-depleted areas. Adaptation to low nutrients and hypoxia supports glioblastoma cell survival, progression and therapeutic resistance. However, specific mechanisms promoting cellular survival under nutrient and O2 deprivation remain incompletely understood. Here, we show that miR-124 expression is negatively correlated with a hypoxic gene signature in glioblastoma patient samples, suggesting that low miR-124 levels contribute to pro-survival adaptive pathways in this disease. As miR-124 expression is repressed in various cancer types (including glioblastoma), we quantified miR-124 abundance in normoxic and hypoxic regions in glioblastoma patient tissue, and investigated whether ectopic miR-124 expression compromises cell survival during tumor ischemia. Our results indicate that miR-124 levels are further diminished in hypoxic/ischemic regions within individual glioblastoma patient samples, compared with regions replete in O2 and nutrients. Importantly, we also show that increased miR-124 expression affects the ability of tumor cells to survive under O2 and/or nutrient deprivation. Moreover, miR-124 re-expression increases cell death in vivo and enhances the survival of mice bearing intracranial xenograft tumors. miR-124 exerts this phenotype in part by directly regulating TEAD1, MAPK14/p38α and SERP1, factors involved in cell proliferation and survival under stress. Simultaneous suppression of these miR-124 targets results in similar levels of cell death as caused by miR-124 restoration. Importantly, we further demonstrate that SERP1 reintroduction reverses the hypoxic cell death elicited by miR-124, indicating the importance of SERP1 in promoting tumor cell survival. In support of our experimental data, we observed a significant correlation between high SERP1 levels and poor patient outcome in glioblastoma patients. Collectively, among the many pro-tumorigeneic properties of miR-124 repression in glioblastoma, we delineated a novel role in promoting tumor cell survival under stressful microenvironments, thereby supporting tumor progression.

Interferon receptor signaling in malignancy: a network of cellular pathways defining biological outcomes

IFNs are cytokines with important antiproliferative activity and exhibit key roles in immune surveillance against malignancies. Early work initiated over three decades ago led to the discovery of IFN receptor activated Jak-Stat pathways and provided important insights into mechanisms for transcriptional activation of IFN-stimulated genes (ISG) that mediate IFN biologic responses. Since then, additional evidence has established critical roles for other receptor-activated signaling pathways in the induction of IFN activities. These include MAPK pathways, mTOR cascades, and PKC pathways. In addition, specific miRNAs appear to play a significant role in the regulation of IFN signaling responses. This review focuses on the emerging evidence for a model in which IFNs share signaling elements and pathways with growth factors and tumorigenic signals but engage them in a distinctive manner to mediate antiproliferative and antiviral responses.

Role of p38 MAP Kinase Signal Transduction in Solid Tumors

Mitogen-activated protein kinases (MAPKs) mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the main subgroups, the p38 MAP kinases, has been implicated in a wide range of complex biologic processes, such as cell proliferation, cell differentiation, cell death, cell migration, and invasion. Dysregulation of p38 MAPK levels in patients are associated with advanced stages and short survival in cancer patients (e.g., prostate, breast, bladder, liver, and lung cancer). p38 MAPK plays a dual role as a regulator of cell death, and it can either mediate cell survival or cell death depending not only on the type of stimulus but also in a cell type specific manner. In addition to modulating cell survival, an essential role of p38 MAPK in modulation of cell migration and invasion offers a distinct opportunity to target this pathway with respect to tumor metastasis. The specific function of p38 MAPK appears to depend not only on the cell type but also on the stimuli and/or the isoform that is activated. p38 MAPK signaling pathway is activated in response to diverse stimuli and mediates its function by components downstream of p38. Extrapolation of the knowledge gained from laboratory findings is essential to address the clinical significance of p38 MAPK signaling pathways. The goal of this review is to provide an overview on recent progress made in defining the functions of p38 MAPK pathways with respect to solid tumor biology and generate testable hypothesis with respect to the role of p38 MAPK as an attractive target for intervention of solid tumors.

Oncolytic polio virotherapy of cancer

Recently, the century-old idea of targeting cancer with viruses (oncolytic viruses) has come of age, and promise has been documented in early stage and several late-stage clinical trials in a variety of cancers. Although originally prized for their direct tumor cytotoxicity (oncolytic virotherapy), recently, the proinflammatory and immunogenic effects of viral tumor infection (oncolytic immunotherapy) have come into focus. Indeed, a capacity for eliciting broad, sustained antineoplastic effects stemming from combined direct viral cytotoxicity, innate antiviral activation, stromal proinflammatory stimulation, and recruitment of adaptive immune effector responses is the greatest asset of oncolytic viruses. However, it also is the source for enormous mechanistic complexity that must be considered for successful clinical translation. Because of fundamentally different relationships with their hosts (malignant or not), diverse replication strategies, and distinct modes of tumor cytotoxicity/killing, oncolytic viruses should not be referred to collectively. These agents must be evaluated based on their individual merits. In this review, the authors highlight key mechanistic principles of cancer treatment with the polio:rhinovirus chimera PVSRIPO and their implications for oncolytic immunotherapy in the clinic.

Selective anticancer effects of a synthetic flavagline on human Oct4-expressing cancer stem-like cells via a p38 MAPK-dependent caspase-3-dependent pathway

Cancer stem cells (CSCs) are considered as the initiators of the carcinogenic process and are therefore emerging targets for innovative anticancer therapies. In order to evaluate the anticancer chemopreventive activity of flavagline derivatives, we used the pluripotent teratocarcinomal cell as a model of Oct4-expressing cancer stem-like cell and determined the underlying cellular and molecular mechanisms induced by a synthetic flavagline. We precisely investigated the effects of the flavagline derivative FL3 on the human embryonal carcinoma (EC) cell line NT2/D1 and compared the responses to those of a normal more restrictive pluripotent stem cell line (i.e. BJ fibroblast cell line). FL3 selectively inhibited the proliferation of NT2/D1 cells by inducing G1 phase cell cycle arrest in a dose-dependent manner. Moreover, FL3 treatment specifically triggered apoptosis in association with an induction of the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and caspase-3 activation followed by a drastic downregulation of the master regulator of stemness Oct4. Forced inhibition of p38 MAPK activity by the specific pharmacological inhibitor SB203580 or by p38 MAPK gene knockdown using small-interfering RNA (siRNA) counteracted the effects of FL3, demonstrating that its chemopreventive action is related to growth inhibition and a p38-dependent caspase-3-dependent induction of apoptosis in Oct4-expressing CSCs. This study also shows that FL3 selectively kills poorly differentiated and highly aggressive carcinomal cells, but has little effect on normal stem-like cells. Thus FL3 offers great promise for cancer treatment since it is able to target the carcinogenic process without affecting normal cells.

Brain microRNAs and insights into biological functions and therapeutic potential of brain enriched miRNA-128

MicroRNAs, the non-coding single-stranded RNA of 19–25 nucleotides are emerging as robust players of gene regulation. Plethora of evidences support that the ability of microRNAs to regulate several genes of a pathway or even multiple cross talking pathways have significant impact on a complex regulatory network and ultimately the physiological processes and diseases. Brain being a complex organ with several cell types, expresses more distinct miRNAs than any other tissues. This review aims to discuss about the microRNAs in brain development, function and their dysfunction in brain tumors. We also provide a comprehensive summary of targets of brain specific and brain enriched miRNAs that contribute to the diversity and plasticity of the brain. In particular, we uncover recent findings on miRNA-128, a brain-enriched microRNA that is induced during neuronal differentiation and whose aberrant expression has been reported in several cancers. This review describes the wide spectrum of targets of miRNA-128 that have been identified till date with potential roles in apoptosis, angiogenesis, proliferation, cholesterol metabolism, self renewal, invasion and cancer progression and how this knowledge might be exploited for the development of future miRNA-128 based therapies for the treatment of cancer as well as metabolic diseases.