A novel kinase cascade triggered by stress and heat shock that stimulates MAPKAP kinase-2 and phosphorylation of the small heat shock proteins

An insight into crosstalk among multiple signalling pathways contributing to the pathophysiology of PTSD and depressive disorders

Post-traumatic stress disorder (PTSD) and depressive disorders represent two significant mental health challenges with substantial global prevalence. These are debilitating conditions characterized by persistent, often comorbid, symptoms that severely impact an individual's quality of life. Both PTSD and depressive disorders are often precipitated by exposure to traumatic events or chronic stress. The profound impact of PTSD and depressive disorders on individuals and society necessitates a comprehensive exploration of their shared and distinct pathophysiological features. Although the activation of the stress system is essential for maintaining homeostasis, the ability to recover from it after diminishing the threat stimulus is also equally important. However, little is known about the main reasons for individuals' differential susceptibility to external stressful stimuli. The solution to this question can be found by delving into the interplay of stress with the cognitive and emotional processing of traumatic incidents at the molecular level. Evidence suggests that dysregulation in these signalling cascades may contribute to the persistence and severity of PTSD and depressive symptoms. The treatment strategies available for this disorder are antidepressants, which have shown good efficiency in normalizing symptom severity; however, their efficacy is limited in most individuals. This calls for the exploration and development of innovative medications to address the treatment of PTSD. This review delves into the intricate crosstalk among multiple signalling pathways implicated in the development and manifestation of these mental health conditions. By unravelling the complexities of crosstalk among multiple signalling pathways, this review aims to contribute to the broader knowledge base, providing insights that could inform the development of targeted interventions for individuals grappling with the challenges of PTSD and depressive disorders.

Regulation of Epithelial and Endothelial Barriers by Molecular Chaperones

The integrity and permeability of epithelial and endothelial barriers depend on the formation of tight junctions, adherens junctions, and a junction-associated cytoskeleton. The establishment of this junction-cytoskeletal module relies on the correct folding and oligomerization of its protein components. Molecular chaperones are known regulators of protein folding and complex formation in different cellular compartments. Mammalian cells possess an elaborate chaperone network consisting of several hundred chaperones and co-chaperones. Only a small part of this network has been linked, however, to the regulation of intercellular adhesions, and the systematic analysis of chaperone functions at epithelial and endothelial barriers is lacking. This review describes the functions and mechanisms of the chaperone-assisted regulation of intercellular junctions. The major focus of this review is on heat shock protein chaperones, their co-chaperones, and chaperonins since these molecules are the focus of the majority of the articles published on the chaperone-mediated control of tissue barriers. This review discusses the roles of chaperones in the regulation of the steady-state integrity of epithelial and vascular barriers as well as the disruption of these barriers by pathogenic factors and extracellular stressors. Since cytoskeletal coupling is essential for junctional integrity and remodeling, chaperone-assisted assembly of the actomyosin cytoskeleton is also discussed.

Discovery of N-Benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine as a Potential Antifungal Agent against Sporidia Growth and Teliospore Germination of Sporisorium scitamineum

The cultivation of sugar cane using perennial roots is the primary planting method, which is one of the reasons for the serious occurrence of sugar cane smut disease caused by the basidiomycetous fungus Sporisorium scitamineum in the sugar cane perennial root planting area. Consequently, it is crucial to eliminate pathogens from perennial sugar cane buds. In this study, we found that MAP kinase Hog1 is necessary for heat stress resistance. Subsequent investigations revealed a significant reduction in the expression of the heat shock protein 104-encoding gene, SsHSP104, in the ss1hog1Δ mutant. Additionally, the overexpression of SsHSP104 partially restored colony growth in the ss1hog1Δ strain following heat stress treatment, demonstrating the crucial role of SsHsp104 in SsHog1-mediated heat stress tolerance. Hence, we constructed the ss1hsp104:eGFP fusion strain in the wild type of S. scitamineum to identify small-molecule compounds that could inhibit the heat stress response, leading to the discovery of N-benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine as a potential compound that targets the SsHog1 mediation SsHsp104 pathway during heat treatment. Furthermore, the combination of N-benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine and warm water treatment (45 °C for 15 min) inhibits the growth of S. scitamineum and teliospore germination, thereby reducing the occurrence of sugar cane smut diseases and indicating its potential for eliminating pathogens from perennial sugar cane buds. In conclusion, these findings suggest that N-benzyl-4-(1-bromonaphthalen-2-yl)oxybutan-1-amine is promising as a targeted compound for the SsHog1-mediated SsHsp104 pathway and may enable the reduction of hot water treatment duration and/or temperature, thereby limiting the occurrence of sugar cane smut diseases caused by S. scitamineum.

The Multifaceted Functions of Prion Protein (PrPC) in Cancer

The cellular prion protein (PrPC) is a glycoprotein anchored to the cell surface by glycosylphosphatidylinositol (GPI). PrPC is expressed both in the brain and in peripheral tissues. Investigations on PrPC's functions revealed its direct involvement in neurodegenerative and prion diseases, as well as in various physiological processes such as anti-oxidative functions, copper homeostasis, trans-membrane signaling, and cell adhesion. Recent findings have revealed the ectopic expression of PrPC in various cancers including gastric, melanoma, breast, colorectal, pancreatic, as well as rare cancers, where PrPC promotes cellular migration and invasion, tumor growth, and metastasis. Through its downstream signaling, PrPC has also been reported to be involved in resistance to chemotherapy and tumor cell apoptosis. This review summarizes the variance of expression of PrPC in different types of cancers and discusses its roles in their development and progression, as well as its use as a potential target to treat such cancers.

The heat shock protein Hsp27 controls mitochondrial function by modulating ceramide generation

Sphingolipids have key functions in membrane structure and cellular signaling. Ceramide is the central molecule of the sphingolipid metabolism and is generated by ceramide synthases (CerS) in the de novo pathway. Despite their critical function, mechanisms regulating CerS remain largely unknown. Using an unbiased proteomics approach, we find that the small heat shock protein 27 (Hsp27) interacts specifically with CerS1 but not other CerS. Functionally, our data show that Hsp27 acts as an endogenous inhibitor of CerS1. Wild-type Hsp27, but not a mutant deficient in CerS1 binding, inhibits CerS1 activity. Additionally, silencing of Hsp27 enhances CerS1-generated ceramide accumulation in cells. Moreover, phosphorylation of Hsp27 modulates Hsp27-CerS1 interaction and CerS1 activity in acute stress-response conditions. Biologically, we show that Hsp27 knockdown impedes mitochondrial function and induces lethal mitophagy in a CerS1-dependent manner. Overall, we identify an important mode of CerS1 regulation and CerS1-mediated mitophagy through protein-protein interaction with Hsp27.

Differential Modulation of the Phosphoproteome by the MAP Kinases Isoforms p38α and p38β

The p38 members of the mitogen-activated protein kinases (MAPKs) family mediate various cellular responses to stress conditions, inflammatory signals, and differentiation factors. They are constitutively active in chronic inflammatory diseases and some cancers. The differences between their transient effects in response to signals and the chronic effect in diseases are not known. The family is composed of four isoforms, of which p38α seems to be abnormally activated in diseases. p38α and p38β are almost identical in sequence, structure, and biochemical and pharmacological properties, and the specific unique effects of each of them, if any, have not yet been revealed. This study aimed to reveal the specific effects induced by p38α and p38β, both when transiently activated in response to stress and when chronically active. This was achieved via large-scale proteomics and phosphoproteomics analyses using stable isotope labeling of two experimental systems: one, mouse embryonic fibroblasts (MEFs) deficient in each of these p38 kinases and harboring either an empty vector or vectors expressing p38αWT, p38βWT, or intrinsically active variants of these MAPKs; second, induction of transient stress by exposure of MEFs, p38α-/-, and p38β-/- MEFs to anisomycin. Significant differences in the repertoire of the proteome and phosphoproteome between cells expressing active p38α and p38β suggest distinct roles for each kinase. Interestingly, in both cases, the constitutive activation induced adaptations of the cells to the chronic activity so that known substrates of p38 were downregulated. Within the dramatic effect of p38s on the proteome and phosphoproteome, some interesting affected phosphorylation sites were those found in cancer-associated p53 and Hspb1 (HSP27) proteins and in cytoskeleton-associated proteins. Among these, was the stronger direct phosphorylation by p38α of p53-Ser309, which was validated on the Ser315 in human p53. In summary, this study sheds new light on the differences between chronic and transient p38α and p38β signaling and on the specific targets of these two kinases.

2-phenylacetamide Separated from the seed of Lepidium apetalum Willd. inhibited renal fibrosis via MAPK pathway mediated RAAS and oxidative stress in SHR Rats

BACKGROUND

Renal fibrosis with Renin-angiotensin-aldosterone system (RAAS) activation and oxidative stress are one of the major complications in hypertension. 2-phenylacetamide (PA), a major active component of Lepidium apetalum Willd. (L.A), has numerous pharmacological effects. Its analogues have the effect of anti-renal fibrosis and alleviating renal injury. This study aims to explore the underlying mechanism of PA for regulating the renal fibrosis in SHR based on the MAPK pathway mediated RAAS and oxidative stress.

METHODS

The SHR rats were used as the hypertension model, and the WKY rats were used as the control group. The blood pressure (BP), urine volume were detected every week. After PA treatment for 4 weeks, the levels of RAAS, inflammation and cytokines were measured by Enzyme-Linked Immunosorbnent Assay (ELISA). Hematoxylin-Eosin staining (HE), Masson and Immunohistochemistry (IHC) were used to observe the renal pathology, collagen deposition and fibrosis. Western blot was used to examine the MAPK pathway in renal. Finally, the SB203580 (p38 MAPK inhibitor) antagonism assay in the high NaCl-induced NRK52e cells was used, together with In-Cell Western (ICW), Flow Cytometry (FCM), High Content Screening (HCS) and ELISA to confirm the potential pharmacological mechanism.

RESULTS

PA reduced the BP, RAAS, inflammation and cytokines, promoted the urine, and relieved renal pathological injury and collagen deposition, repaired renal fibrosis, decreased the expression of NADPH Oxidase 4 (NOX4), transforming growth factor-β (TGF-β), SMAD3 and MAPK signaling pathway in SHR rats. Meanwhile,,the role of PA could be blocked by p38 antagonist SB203580 effectively in the high NaCl-induced NRK52e cells. Moreover, molecular docking indicated that PA occupied the ligand binding sites of p38 MAPK.

CONCLUSION

PA inhibited renal fibrosis via MAPK signalling pathway mediated RAAS and oxidative stress in SHR Rats.

Medicinal chemistry approaches to target the MNK-eIF4E axis in cancer

Aberrant translation of proteins that promote cell proliferation is an essential factor that defines oncogenic processes and cancer. The process for ribosomal translation of proteins from mRNA requires an essential initiation step which is controlled by the protein eIF4E, which binds the RNA 5'-cap and forms the eIF4F complex that subsequently translates protein. Typically, eIF4E is activated by phosphorylation on Ser209 by MNK1 and MNK2 kinases. Substantial work has shown that eIF4E and MNK1/2 are dysregulated in many cancers and this axis has therefore become an active area of interest for developing new cancer therapeutics. This review summarizes and discusses recent work to develop small molecules that target different steps in the MNK-eIF4E axis as potential cancer therapeutics. The aim of this review is to cover the breadth of different molecular approaches being taken and the medicinal chemistry basis for their optimization and testing as new cancer therapeutics.

Drug Design in the Exascale Era: A Perspective from Massively Parallel QM/MM Simulations

The initial phases of drug discovery - in silico drug design - could benefit from first principle Quantum Mechanics/Molecular Mechanics (QM/MM) molecular dynamics (MD) simulations in explicit solvent, yet many applications are currently limited by the short time scales that this approach can cover. Developing scalable first principle QM/MM MD interfaces fully exploiting current exascale machines - so far an unmet and crucial goal - will help overcome this problem, opening the way to the study of the thermodynamics and kinetics of ligand binding to protein with first principle accuracy. Here, taking two relevant case studies involving the interactions of ligands with rather large enzymes, we showcase the use of our recently developed massively scalable Multiscale Modeling in Computational Chemistry (MiMiC) QM/MM framework (currently using DFT to describe the QM region) to investigate reactions and ligand binding in enzymes of pharmacological relevance. We also demonstrate for the first time strong scaling of MiMiC-QM/MM MD simulations with parallel efficiency of ∼70% up to >80,000 cores. Thus, among many others, the MiMiC interface represents a promising candidate toward exascale applications by combining machine learning with statistical mechanics based algorithms tailored for exascale supercomputers.

Iodine-Biofortified Lettuce Can Promote Mitochondrial Dependent Pathway of Apoptosis in Human Gastrointestinal Cancer Cells

Previously, our research provided evidence that exposure of gastric and colon cancer cells to extracts from iodine-biofortified lettuce leads to a reduction of cell viability and proliferation through cell cycle arrest and upregulation of pro-apoptotic genes. The aim of the present study was to determine the potential cellular mechanisms of induction of cell death in human gastrointestinal cancer cell lines after treatment with iodine-biofortified lettuce. We demonstrated that extracts from lettuce enriched with iodine induce apoptosis in gastric AGS and colon HT-29 cancer cells and the mechanism of programmed cell death may be triggered and executed through different signaling pathways, depending on the type of cells. Western blot analysis revealed that iodine-fortified lettuce leads to cell death through the release of cytochrome c to the cytosolic fraction and activation of the primary drivers of apoptosis: caspase-3, caspase-7, and caspase-9. Furthermore, we have reported that apoptotic effects of lettuce extracts may be mediated by poly (ADP-ribose) polymerase (PARP) and activation of pro-apoptotic Bcl-2 family proteins such as Bad, Bax, and BID. We also observed mitochondrial dysfunction with the dissipation of the mitochondrial membrane potential in cells exposed to lettuce extracts. Taken together, these results indicate that the organic form of iodine such as 5-ISA and 3,5-diISA is an important factor in the activation of intrinsic mitochondrial apoptotic pathway in AGS and HT-29 cancer cells in a p53-independent manner.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

Cellular stress induces non-canonical activation of the receptor tyrosine kinase EphA2 through the p38-MK2-RSK signaling pathway

The receptor tyrosine kinase EphA2 is overexpressed in malignant tumors. We previously reported that non-canonical EphA2 phosphorylation at Ser-897 was catalyzed by p90 ribosomal S6 kinase (RSK) via the MEK-ERK pathway in ligand- and tyrosine kinase-independent manners. Non-canonical EphA2 activation plays a key role in tumor progression; however, its activation mechanism remains unclear. In the present study, we focused on cellular stress signaling as a novel inducer of non-canonical EphA2 activation. p38, instead of ERK in the case of epidermal growth factor signaling, activated RSK-EphA2 under cellular stress conditions, including anisomycin, cisplatin and high osmotic stress. Notably, p38 activated the RSK-EphA2 axis via downstream MAPK-activated protein kinase 2 (MK2). Furthermore, MK2 directly phosphorylated both RSK1 Ser-380 and RSK2 Ser-386, critical residues for the activation of their N-terminal kinases, which is consistent with the result showing that the C-terminal kinase domain of RSK1 was dispensable for MK2-mediated EphA2 phosphorylation. Moreover, the p38-MK2-RSK-EphA2 axis promoted glioblastoma cell migration induced by temozolomide, a chemotherapeutic agent for the treatment of glioblastoma patients. Collectively, the present results reveal a novel molecular mechanism for non-canonical EphA2 activation under stress conditions in the tumor microenvironment.

p38 MAPK and MKP-1 control the glycolytic program via the bifunctional glycolysis regulator PFKFB3 during sepsis

Hyperlactatemia often occurs in critically ill patients during severe sepsis/septic shock and is a powerful predictor of mortality. Lactate is the end product of glycolysis. While hypoxia due to inadequate oxygen delivery may result in anaerobic glycolysis, sepsis also enhances glycolysis under hyperdynamic circulation with adequate oxygen delivery. However, the molecular mechanisms involved are not fully understood. Mitogen-activated protein kinase (MAPK) families regulate many aspects of the immune response during microbial infections. MAPK phosphatase (MKP)-1 serves as a feedback control mechanism for p38 and JNK MAPK activities via dephosphorylation. Here, we found that mice deficient in Mkp-1 exhibited substantially enhanced expression and phosphorylation of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase (PFKFB) 3, a key enzyme that regulates glycolysis following systemic Escherichia coli infection. Enhanced PFKFB3 expression was observed in a variety of tissues and cell types, including hepatocytes, macrophages, and epithelial cells. In bone marrow-derived macrophages, Pfkfb3 was robustly induced by both E. coli and lipopolysaccharide, and Mkp-1 deficiency enhanced PFKFB3 expression with no effect on Pfkfb3 mRNA stability. PFKFB3 induction was correlated with lactate production in both WT and Mkp-1-/- bone marrow-derived macrophage following lipopolysaccharide stimulation. Furthermore, we determined that a PFKFB3 inhibitor markedly attenuated lactate production, highlighting the critical role of PFKFB3 in the glycolysis program. Finally, pharmacological inhibition of p38 MAPK, but not JNK, substantially attenuated PFKFB3 expression and lactate production. Taken together, our studies suggest a critical role of p38 MAPK and MKP-1 in the regulation of glycolysis during sepsis.

VEGF Stimulates Activation of ERK5 in the Absence of C-Terminal Phosphorylation Preventing Nuclear Localization and Facilitating AKT Activation in Endothelial Cells

Extracellular-signal-regulated kinase 5 (ERK5) is critical for normal cardiovascular development. Previous studies have defined a canonical pathway for ERK5 activation, showing that ligand stimulation leads to MEK5 activation resulting in dual phosphorylation of ERK5 on Thr218/Tyr220 residues within the activation loop. ERK5 then undergoes a conformational change, facilitating phosphorylation on residues in the C-terminal domain and translocation to the nucleus where it regulates MEF2 transcriptional activity. Our previous research into the importance of ERK5 in endothelial cells highlighted its role in VEGF-mediated tubular morphogenesis and cell survival, suggesting that ERK5 played a unique role in endothelial cells. Our current data show that in contrast to EGF-stimulated HeLa cells, VEGF-mediated ERK5 activation in human dermal microvascular endothelial cells (HDMECs) does not result in C-terminal phosphorylation of ERK5 and translocation to the nucleus, but instead to a more plasma membrane/cytoplasmic localisation. Furthermore, the use of small-molecule inhibitors to MEK5 and ERK5 shows that instead of regulating MEF2 activity, VEGF-mediated ERK5 is important for regulating AKT activity. Our data define a novel pathway for ERK5 activation in endothelial cells leading to cell survival.

Characterization of p38α signaling networks in cancer cells using quantitative proteomics and phosphoproteomics

p38α (encoded by MAPK14) is a protein kinase that regulates cellular responses to almost all types of environmental and intracellular stresses. Upon activation, p38α phosphorylates many substrates both in the cytoplasm and nucleus, allowing this pathway to regulate a wide variety of cellular processes. While the role of p38α in the stress response has been widely investigated, its implication in cell homeostasis is less understood. To investigate the signaling networks regulated by p38α in proliferating cancer cells, we performed quantitative proteomic and phosphoproteomic analyses in breast cancer cells in which this pathway had been either genetically targeted or chemically inhibited. Our study identified with high confidence 35 proteins and 82 phosphoproteins (114 phosphosites) that are modulated by p38α, and highlighted the implication of various protein kinases, including MK2 and mTOR, in the p38α-regulated signaling networks. Moreover, functional analyses revealed an important contribution of p38α to the regulation of cell adhesion, DNA replication and RNA metabolism. Indeed, we provide experimental evidence supporting that p38α facilitates cancer cell adhesion, and showed that this p38α function is likely mediated by the modulation of the adaptor protein ArgBP2. Collectively, our results illustrate the complexity of the p38α regulated signaling networks, provide valuable information on p38α-dependent phosphorylation events in cancer cells, and document a mechanism by which p38α can regulate cell adhesion.

Selenium ameliorates inflammation by decreasing autophagic flux and mitogen-activated protein kinase signalling on experimentally induced rat periapical lesions

AIM

To reveal the molecular mechanisms that targets mitogen-activated protein kinase (MAPK) signalling and the autophagic flux and to investigate the possible effects of the systemic administration of selenium (Se) on experimentally induced rat periapical lesions.

METHODOLOGY

Thirty adult Sprague-Dawley rats were divided equally into negative control, positive control and Se groups. In the positive control and Se groups, the pulp chambers of their mandibular first molars were exposed to the oral environment to induce periapical lesions The Se group received daily intraperitoneal injections of Se at a dose of 0.1 mg kg^-1 . After 28 days, the amount of bone destruction; severity of inflammation; penetration of microorganisms along the root canal; collagen degradation in periodontal ligament; interleukin (IL)-6, hypoxia-inducible factor-1 (HIF-1), cyclooxygenase-2 (COX-2) and caspase-3 expression; autophagic flux; and p38 MAPK signalling were evaluated using radiographic, histopathological, Gram staining, picrosirius red stain, immunohistochemical, quantitative real-time polymerase chain (qRT-PCR) and Western blot methods, respectively. These data were analysed through the Kruskal-Wallis and Dunnett's tests (p < .05).

RESULTS

The area of radiographic periapical bone loss, histopathological scores, the area of periapical bone loss and the scores for the bacteria localisation, the intensity of immunohistochemical staining for IL-6, HIF-1, COX-2 and caspase-3 in the Se group was significantly less than those of the positive control group (p < .01). The mRNA expression levels of Beclin-1, Atg3, Atg5, Atg7 and Atg16L1 were lower in the Se group than in the positive control group (p < .01). The protein expressions of Beclin-1, Atg5 and LC3-II, the phosphorylation ratio of the p38 MAPK and the ratios of LC3II/LC3I were significantly higher (p < .05) in the positive control and Se groups. On the contrary, the expression of the p62/SQSTM1 protein was significantly lower (p < .05) in the positive control and Se groups than in the negative control group.

CONCLUSION

The induction of periapical lesions in rats increased autophagic flux and activated p38 MAPK signal transduction processes. Se suppressed the inflammatory process, reduced bone destruction and both the autophagic flux and p38 MAPK activation.

P38 MAPK and Radiotherapy: Foes or Friends?

Over the last 30 years, the study of the cellular response to ionizing radiation (IR) has increased exponentially. Among the various signaling pathways affected by IR, p38 MAPK has been shown to be activated both in vitro and in vivo, with involvement in key processes triggered by IR-mediated genotoxic insult, such as the cell cycle, apoptosis or senescence. However, we do not yet have a definitive clue about the role of p38 MAPK in terms of radioresistance/sensitivity and its potential use to improve current radiotherapy. In this review, we summarize the current knowledge on this family of MAPKs in response to IR as well as in different aspects related to radiotherapy, such as their role in the control of REDOX, fibrosis, and in the radiosensitizing effect of several compounds.

Revisiting the multisite phosphorylation that produces the M-phase supershift of key mitotic regulators

The term M-phase supershift denotes the phosphorylation-dependent substantial increase in the apparent molecular weight of numerous proteins of varied biological functions during M-phase induction. Although the M-phase supershift of multiple key mitotic regulators has been attributed to the multisite phosphorylation catalyzed by the Cdk1/cyclin B/Cks complex, this view is challenged by multiple lines of paradoxical observations. To solve this problem, we reconstituted the M-phase supershift of Xenopus Cdc25C, Myt1, Wee1A, APC3 and Greatwall in Xenopus egg extracts and characterized the supershift-producing phosphorylations. Our results demonstrate that their M-phase supershifts are each due to simultaneous phosphorylation of a considerable portion of S/T/Y residues in a long intrinsically disordered region that is enriched in both S/T residues and S/TP motifs. Although the major mitotic kinases in Xenopus egg extracts, Cdk1, MAPK, Plx1 and RSK2, are able to phosphorylate the five mitotic regulators, they are neither sufficient nor required to produce the M-phase supershift. Accordingly, inhibition of the four major mitotic kinase activities in Xenopus oocytes did not inhibit the M-phase supershift in okadaic acid-induced oocyte maturation. These findings indicate that the M-phase supershift is produced by a previously unrecognized category of mitotic phosphorylation that likely plays important roles in M-phase induction.

The Developmental Transcription Factor p63 Is Redeployed to Drive Allergic Skin Inflammation through Phosphorylation by p38α

Keratinocytes, the epithelial cells of the skin, reprogram their gene expression and produce immune effector molecules when exposed to environmental and endogenous triggers of inflammation. It remains unclear how keratinocytes process physiological signals generated during skin irritation and switch from a homeostatic to an inflammatory state. In this article, we show that the stress-activated protein kinase p38α is crucial for keratinocytes to prompt changes in their transcriptome upon cytokine stimulation and drive inflammation in allergen-exposed skin. p38α serves this function by phosphorylating p63, a transcription factor essential for the lineage identity and stemness of the skin epithelium. Phosphorylation by p38α alters the activity of p63 and redeploys this developmental transcription factor to a gene expression program linked to inflammation. Genetic ablation and pharmacological inhibition of p38α or the p38α-p63 target gene product MMP13 attenuate atopic dermatitis-like disease in mice. Our study reveals an epithelial molecular pathway promoting skin inflammation and actionable through treatment with topical small-molecule therapeutics.

Small Molecule Arranged Thermal Proximity Coaggregation (smarTPCA)-A Novel Approach to Characterize Protein-Protein Interactions in Living Cells by Similar Isothermal Dose-Responses

Chemical biology and the application of small molecules has proven to be a potent perturbation strategy, especially for the functional elucidation of proteins, their networks, and regulators. In recent years, the cellular thermal shift assay (CETSA) and its proteome-wide extension, thermal proteome profiling (TPP), have proven to be effective tools for identifying interactions of small molecules with their target proteins, as well as off-targets in living cells. Here, we asked the question whether isothermal dose-response (ITDR) CETSA can be exploited to characterize secondary effects downstream of the primary binding event, such as changes in post-translational modifications or protein-protein interactions (PPI). By applying ITDR-CETSA to MAPK14 kinase inhibitor treatment of living HL-60 cells, we found similar dose-responses for the direct inhibitor target and its known interaction partners MAPKAPK2 and MAPKAPK3. Extension of the dose-response similarity comparison to the proteome wide level using TPP with compound concentration range (TPP-CCR) revealed not only the known MAPK14 interaction partners MAPKAPK2 and MAPKAPK3, but also the potentially new intracellular interaction partner MYLK. We are confident that dose-dependent small molecule treatment in combination with ITDR-CETSA or TPP-CCR similarity assessment will not only allow discrimination between primary and secondary effects, but will also provide a novel method to study PPI in living cells without perturbation by protein modification, which we named "small molecule arranged thermal proximity coaggregation" (smarTPCA).

Palmitoylation couples the kinases DLK and JNK3 to facilitate prodegenerative axon-to-soma signaling

Dual leucine-zipper kinase (DLK; a MAP3K) mediates neuronal responses to diverse injuries and insults through the c-Jun N-terminal kinase (JNK) family of mitogen-activated protein kinases (MAPKs). Here, we identified two ways through which DLK is coupled to the neural-specific isoform JNK3 to control prodegenerative signaling. JNK3 catalyzed positive feedback phosphorylation of DLK that further activated DLK and locked the DLK-JNK3 module in a highly active state. Neither homologous MAP3Ks nor a homologous MAPK could support this positive feedback loop. Unlike the related JNK1 isoform JNK2 and JNK3 promote prodegenerative axon-to-soma signaling and were endogenously palmitoylated. Moreover, palmitoylation targeted both DLK and JNK3 to the same axonal vesicles, and JNK3 palmitoylation was essential for axonal retrograde signaling in response to optic nerve crush injury in vivo. These findings provide previously unappreciated insights into DLK-JNK signaling relevant to neuropathological conditions and answer long-standing questions regarding the selective prodegenerative roles of JNK2 and JNK3.

Weighted correlation network analysis revealed novel long non-coding RNAs for colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide, which after breast, lung and, prostate cancers, is the fourth prevalent cancer in the United States. Long non-coding RNAs (lncRNAs) have an essential role in the pathogenesis of CRC. Therefore, bioinformatics studies on lncRNAs and their target genes have potential importance as novel biomarkers. In the current study, publicly available microarray gene expression data of colorectal cancer (GSE106582) was analyzed with the Limma, Geoquery, Biobase package. Afterward, identified differentially expressed lncRNAs and their target genes were inserted into Weighted correlation network analysis (WGCNA) to obtain modules and hub genes. A total of nine differentially expressed lncRNAs (LINC01018, ITCH-IT, ITPK1-AS1, FOXP1-IT1, FAM238B, PAXIP1-AS1, ATP2B1-AS1, MIR29B2CHG, and SNHG32) were identified using microarray data analysis. The WGCNA has identified several hub genes for black (LMOD3, CDKN2AIPNL, EXO5, ZNF69, BMS1P5, METTL21A, IL17RD, MIGA1, CEP19, FKBP14), blue (CLCA1, GUCA2A, UGT2B17, DSC2, CA1, AQP8, ITLN1, BEST4, KLF4, IQCF6) and turquoise (PAFAH1B1, LMNB1, CACYBP, GLO1, PUM3, POC1A, ASF1B, SDCCAG3, ASNS, PDCD2L) modules. The findings of the current study will help to improve our understanding of CRC. Moreover, the hub genes that we have identified could be considered as possible prognostic/diagnostic biomarkers. This study led to the determination of nine lncRNAs with no previous association with CRC development.

MAPK-Activated Protein Kinases: Servant or Partner?

Mitogen-activated protein kinase (MAPK)-activated protein kinases (MAPKAPKs) are defined by their exclusive activation by MAPKs. They can be activated by classical and atypical MAPKs that have been stimulated by mitogens and various stresses. Genetic deletions of MAPKAPKs and availability of highly specific small-molecule inhibitors have continuously increased our functional understanding of these kinases. MAPKAPKs cooperate in the regulation of gene expression at the level of transcription; RNA processing, export, and stability; and protein synthesis. The diversity of stimuli for MAPK activation, the cross talk between the different MAPKs and MAPKAPKs, and the specific substrate pattern of MAPKAPKs orchestrate immediate-early and inflammatory responses in space and time and ensure proper control of cell growth, differentiation, and cell behavior. Hence, MAPKAPKs are promising targets for cancer therapy and treatments for conditions of acute and chronic inflammation, such as cytokine storms and rheumatoid arthritis. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A Potential Probiotic Lactobacillus plantarum JBC5 Improves Longevity and Healthy Aging by Modulating Antioxidative, Innate Immunity and Serotonin-Signaling Pathways in Caenorhabditis elegans

Since the hypothesis of Dr. Elie Metchnikoff on lactobacilli-mediated healthy aging, several microbes have been reported to extend the lifespan with different features of healthy aging. However, a microbe affecting diverse features of healthy aging is of choice for broader acceptance and marketability as a next-generation probiotic. We employed Caenorhabditis elegans as a model to understand the potential of Lactobacillus plantarum JBC5 (LPJBC5), isolated from fermented food sample on longevity and healthy aging as well as their underlying mechanisms. Firstly, LPJBC5 enhanced the mean lifespan of C. elegans by 27.81% compared with control (untreated). LPBC5-induced longevity was accompanied with better aging-associated biomarkers, such as physical functions, fat, and lipofuscin accumulation. Lifespan assay on mutant worms and gene expression studies indicated that LPJBC5-mediated longevity was due to upregulation of the skinhead-1 (skn-1) gene activated through p38 MAPK signaling cascade. Secondly, the activated transcription factor SKN-1 upregulated the expression of antioxidative, thermo-tolerant, and anti-pathogenic genes. In support, LPJBC5 conferred resistance against abiotic and biotic stresses such as oxidative, heat, and pathogen. LPJBC5 upregulated the expression of intestinal tight junction protein ZOO-1 and improved gut integrity. Thirdly, LPJBC5 improved the learning and memory of worms trained on LPJBC5 compared with naive worms. The results showed upregulation of genes involved in serotonin signaling (ser-1, mod-1, and tph-1) in LPJBC5-fed worms compared with control, suggesting that serotonin-signaling was essential for LPJBC5-mediated improved cognitive function. Fourthly, LPJBC5 decreased the fat accumulation in worms by reducing the expression of genes encoding key substrates and enzymes of fat metabolism (i.e., fat-5 and fat-7). Lastly, LPJBC5 reduced the production of reactive oxygen species and improved mitochondrial function, thereby reducing apoptosis in worms. The capability of a single bacterium on pro-longevity and the features of healthy aging, including enhancement of gut integrity and cognitive functions, makes it an ideal candidate for promotion as a next-generation probiotic.

Mitogen-activated protein kinase kinase 7 in inflammatory, cancer, and neurological diseases

Stress-activated mitogen-activated protein kinase kinase 7 (MKK7) is a member of the dual-specificity mitogen-activated protein kinase family. In the human body, MKK7 controls essential physiological processes, including but not limited to proliferation and differentiation in multiple tissues and organs. MKK7, along with the MKK4 pathway, has been implicated in stress-activated activities and biological events that are mediated by c-Jun N-terminal kinase (JNK) signaling. Although numerous studies have been performed to identify the role of JNK in multiple biological processes, there are limited publications that focus on dissecting the independent role of MKK7. Recent research findings have spurred testing via in vivo genetically deficient models, uncovering previously undocumented JNK-independent functions of MKK7. Here we discuss both JNK-dependent and-independent functions of MKK7 in vivo. This review summarizes the role of MKK7 in inflammation, cytokine production, cancer, and neurological diseases.

Role of Particulate Matter from Afghanistan and Iraq in Deployment-Related Lung Disease

Approximately 3 million United States military personnel and contractors were deployed to Southwest Asia and Afghanistan over the past two decades. After returning to the United States, many developed persistent respiratory symptoms, including those due to asthma, rhinosinusitis, bronchiolitis, and others, which we collectively refer to as deployment-related lung diseases (DRLD). The mechanisms of different DRLD have not been well defined. Limited studies from us and others suggest that multiple factors and biological signaling pathways contribute to the onset of DRLD. These include, but are not limited to, exposures to high levels of particulate matter (PM) from sandstorms, burn pit combustion products, improvised explosive devices, and diesel exhaust particles. Once inhaled, these hazardous substances can activate lung immune and structural cells to initiate numerous cell-signaling pathways such as oxidative stress, Toll-like receptors, and cytokine-driven cell injury (e.g., interleukin-33). These biological events may lead to a pro-inflammatory response and airway hyperresponsiveness. Additionally, exposures to PM and other environmental hazards may predispose military personnel and contractors to more severe disease due to the interactions of those hazardous materials with subsequent exposures to allergens and cigarette smoke. Understanding how airborne exposures during deployment contribute to DRLD may identify effective targets to alleviate respiratory diseases and improve quality of life in veterans and active duty military personnel.

The Combination of AHCC and ETAS Decreases Migration of Colorectal Cancer Cells, and Reduces the Expression of LGR5 and Notch1 Genes in Cancer Stem Cells: A Novel Potential Approach for Integrative Medicine

The AHCC standardized extract of cultured Lentinula edodes mycelia, and the standardized extract of Asparagus officinalis stem, trademarked as ETAS, are well known supplements with immunomodulatory and anticancer potential. Several reports have described their therapeutic effects, including antioxidant and anticancer activity and improvement of immune response. In this study we aimed at investigating the effects of a combination of AHCC and ETAS on colorectal cancer cells and biopsies from healthy donors to assess the possible use in patients with colorectal cancer. Our results showed that the combination of AHCC and ETAS was synergistic in inducing a significant decrease in cancer cell growth, compared with single agents. Moreover, the combined treatment induced a significant increase in apoptosis, sparing colonocytes from healthy donors, and was able to induce a strong reduction in migration potential, accompanied by a significant modulation of proteins involved in invasiveness. Finally, combined treatment was able to significantly downregulate LGR5 and Notch1 in SW620 cancer stem cell (CSC) colonospheres. Overall, these findings support the potential therapeutic benefits of the AHCC and ETAS combinatorial treatment for patients with colorectal cancer.

Kinase Inhibition as Treatment for Acute and Chronic Graft-Versus-Host Disease

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is a potentially curative therapy for patients suffering from hematological malignancies via the donor immune system driven graft-versus-leukemia effect. However, the therapy is mainly limited by severe acute and chronic graft-versus-host disease (GvHD), both being life-threatening complications after allo-HCT. GvHD develops when donor T cells do not only recognize remaining tumor cells as foreign, but also the recipient’s tissue, leading to a severe inflammatory disease. Typical GvHD target organs include the skin, liver and intestinal tract. Currently all approved strategies for GvHD treatment are immunosuppressive therapies, with the first-line therapy being glucocorticoids. However, therapeutic options for glucocorticoid-refractory patients are still limited. Novel therapeutic approaches, which reduce GvHD severity while preserving GvL activity, are urgently needed. Targeting kinase activity with small molecule inhibitors has shown promising results in preclinical animal models and clinical trials. Well-studied kinase targets in GvHD include Rho-associated coiled-coil-containing kinase 2 (ROCK2), spleen tyrosine kinase (SYK), Bruton’s tyrosine kinase (BTK) and interleukin-2-inducible T-cell kinase (ITK) to control B- and T-cell activation in acute and chronic GvHD. Janus Kinase 1 (JAK1) and 2 (JAK2) are among the most intensively studied kinases in GvHD due to their importance in cytokine production and inflammatory cell activation and migration. Here, we discuss the role of kinase inhibition as novel treatment strategies for acute and chronic GvHD after allo-HCT.

Downregulation of GNA15 Inhibits Cell Proliferation via P38 MAPK Pathway and Correlates with Prognosis of Adult Acute Myeloid Leukemia With Normal Karyotype

Background

The prognosis of acute myeloid leukemia (AML) with a normal karyotype is highly heterogonous, and the current risk stratification is still insufficient to differentiate patients from high-risk to standard-risk. Changes in some genetic profiles may contribute to the poor prognosis of AML. Although the prognostic value of G protein subunit alpha 15 (GNA15) in AML has been reported based on the GEO (Gene Expression Omnibus) database, the prognostic significance of GNA15 has not been verified in clinical samples. The biological functions of GNA15 in AML development remain open to investigation. This study explored the clinical significance, biological effects and molecular mechanism of GNA15 in AML.

Methods

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression level of GNA15 in blasts of bone marrow specimens from 154 newly diagnosed adult AML patients and 26 healthy volunteers. AML cell lines, Kasumi-1 and SKNO-1, were used for lentiviral transfection. Cell Counting Kit-8 (CCK8) and colony formation assays were used to determine cell proliferation. Cell cycle and apoptosis were analyzed by flow cytometry. The relevant signaling pathways were evaluated by Western blot. The Log-Rank test and Kaplan-Meier were used to evaluate survival rate, and the Cox regression model was used to analyze multivariate analysis. Xenograft tumor mouse model was used for in vivo experiments.

Results

The expression of GNA15 in adult AML was significantly higher than that in healthy individuals. Subjects with high GNA15 expression showed lower overall survival and relapse-free survival in adult AML with normal karyotype. High GNA15 expression was independently correlated with a worse prognosis in multivariate analysis. Knockdown of GNA15 inhibited cell proliferation and cell cycle progression, and induced cell apoptosis in AML cells. GNA15-knockdown induced down-regulation of p-P38 MAPK and its downstream p-MAPKAPK2 and p-CREB. Rescue assays confirmed that P38 MAPK signaling pathway was involved in the inhibition of proliferation mediated by GNA15 knockdown.

Conclusions

In summary, GNA15 was highly expressed in adult AML, and high GNA15 expression was independently correlated with a worse prognosis in adult AML with normal karyotype. Knockdown of GNA15 inhibited the proliferation of AML regulated by the P38 MAPK signaling pathway. Therefore, GNA15 may serve as a potential prognostic marker and a therapeutic target for AML in the future.

Mitogen-activated protein kinase-activated protein kinase-2 (MK2) and its role in cell survival, inflammatory signaling, and migration in promoting cancer

Cancer and the immune system share an intimate relationship. Chronic inflammation increases the risk of cancer occurrence and can also drive inflammatory mediators into the tumor microenvironment enhancing tumor growth and survival. The p38 MAPK pathway is activated both acutely and chronically by stress, inflammatory chemokines, chronic inflammatory conditions, and cancer. These properties have led to extensive efforts to find effective drugs targeting p38, which have been unsuccessful. The immediate downstream serine/threonine kinase and substrate of p38 MAPK, mitogen-activated-protein-kinase-activated-protein-kinase-2 (MK2) protects cells against stressors by regulating the DNA damage response, transcription, protein and messenger RNA stability, and motility. The phosphorylation of downstream substrates by MK2 increases inflammatory cytokine production, drives an immune response, and contributes to wound healing. By binding directly to p38 MAPK, MK2 is responsible for the export of p38 MAPK from the nucleus which gives MK2 properties that make it unique among the large number of p38 MAPK substrates. Many of the substrates of both p38 MAPK and MK2 are separated between the cytosol and nucleus and interfering with MK2 and altering this intracellular translocation has implications for the actions of both p38 MAPK and MK2. The inhibition of MK2 has shown promise in combination with both chemotherapy and radiotherapy as a method for controlling cancer growth and metastasis in a variety of cancers. Whereas the current data are encouraging the field requires the development of selective and well tolerated drugs to target MK2 and a better understanding of its effects for effective clinical use.

Current Insights of Inhibitors of p38 Mitogen-Activated Protein Kinase in Inflammation

BACKGROUND

The inflammatory process is one of the mechanisms by which our body upholds us from pathogens such as parasites, bacteria, viruses, and other harmful microorganisms. Inflammatory stimuli activate many intracellular signaling pathways such as the nuclear factor-kB (NF-kB) pathway and three mitogen-activated protein kinase (MAPK) pathways, which are mediated through extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38. The p38 has evolved as an enticing target in treating many persistent inflammatory diseases. Hence, designing novel p38 inhibitors targeting MAPK pathways has acquired significance.

OBJECTIVE

Peruse to identify the lead target to discover novel p38MAPK inhibitors with different scaffolds having improved selectivity over the prototype drugs.

METHODS

Structure and the binding sites of p38MAPK were focused. Various scaffolds designed for inhibition and the molecules which have entered the clinical trials are discussed.

RESULTS

This review aspires to present the available information on the structure and the 3D binding sites of p38MAPK, various scaffolds designed for imidazole, urea, benzamide, azoles, quinoxaline, chromone, ketone as a potent p38MAPK inhibitors and their SAR studies and the molecules which have entered the clinical trials.

CONCLUSION

The development of successful selective p38MAPK inhibitors in inflammatory diseases is in progress despite all challenges. It was speculated that p38MAPK also plays an important role in treating diseases such as neuroinflammation, arterial inflammation, vascular inflammation, cancer and so on, which are posing the world with treatment challenges. In this review, clinical trials of drugs are discussed related to inflammatory and its related diseases. Research is in progress to design and develop novel p38MAPK inhibitors with minimal side effects.

IGF-1 Facilitates Cartilage Reconstruction by Regulating PI3K/AKT, MAPK, and NF-kB Signaling in Rabbit Osteoarthritis

Purpose

The pathogenesis of osteoarthritis (OA) is characterized by joint degeneration. The pro-inflammatory cytokine interleukin (IL)-1β plays a vital role in the pathogenesis of OA by stimulation of specific signaling pathways like NF-κB, PI3K/Akt, and MAPKs pathways. The catabolic role of growth factors in the OA may be inhibited cytokine-activated pathogen. The purpose of this study was to investigate the potential effects of insulin-like growth factor-1 (IGF-1) on IL-1β-induced apoptosis in rabbit chondrocytes in vitro and in an in vivo rabbit knee OA model.

Methods

In the present study, the OA developed in chondrocyte with the treatment of IL-1β and articular cartilage ruptures by removal of cartilage from the rabbit knee femoral condyle. After IGF-1 treatment, immunohistochemistry and qRT-PCR were identified OA expression with changes in MMPs (matrix metalloproteinases). The production of ROS (intracellular reactive oxygen species) in the OA was detected by flow cytometry. Further, the disease progression was microscopically investigated and pathophysiological changes were analyzed using histology. The NF-κB, PI3K/Akt and P38 (MAPK) specific pathways that are associated with disease progression were also checked using the Western blot technique.

Results

The expression of MMPs and various apoptotic markers are down-regulated following administration of IGF-1 in a dose-dependent fashion while significantly up-regulation of TIMP-1. The results showed that higher levels of ROS were observed upon treatment of chondrocytes and chondral OA with IL-1β. Collectively, our results indicated that IGF-1 protected NF-κB pathway by suppression of PI3K/Akt and MAPKs specific pathways. Furthermore, the macroscopic and pathological investigation showed that it has a chondroprotective effect by the formation of hyaline cartilage.

Conclusion

Our results indicate a protective effect of IGF-1 against OA pathogenesis by inhibition of NF-κB signaling via regulation of the MAPK and PI3K/Akt signaling pathways and prevention of apoptosis by suppression of ROS production.

Binding mechanism of inhibitors to p38α MAP kinase deciphered by using multiple replica Gaussian accelerated molecular dynamics and calculations of binding free energies

The p38α MAP Kinase has been an important target of drug design for treatment of inflammatory diseases and cancers. This work applies multiple replica Gaussian accelerated molecular dynamics (MR-GaMD) simulations and the molecular mechanics generalized Born surface area (MM-GBSA) method to probe the binding mechanism of inhibitors L51, R24 and 1AU to p38α. Dynamics analyses show that inhibitor bindings exert significant effect on conformational changes of the active helix α2 and the conserved DFG loop. The rank of binding free energies calculated with MM-GBSA not only agrees well with that determined by the experimental IC50 values but also suggests that mutual compensation between the enthalpy and entropy changes can improve binding of inhibitors to p38α. The analyses of free energy landscapes indicate that the L51, R24 and 1AU bound p38α display a DFG-out conformation. The residue-based free energy decomposition method is used to evaluate contributions of separate residues to the inhibitor-p38α binding and the results imply that residues V30, V38, L74, L75, I84, T106, H107, L108, M109, L167, F169 and D168 can be utilized as efficient targets of potent inhibitors toward p38α.

Comprehensive bioinformatics analysis reveals kinase activity profiling associated with heart failure

Heart failure is a complex clinical syndrome originating from cardiac injury, which leads to considerable morbidity and mortality. Among the dynamic molecular adaptations occurring in heart failure development, aggravation of the disease is often attributed to global or local abnormality of the kinase. Therefore, the overall monitoring of kinase activity is indispensable. In this study, a bioinformatics analysis method was developed to conduct deep mining of transcriptome and phosphoproteome in failing heart tissue. A total of 982 differentially expressed genes and 9781 phosphorylation sites on 3252 proteins were identified. Via upstream regulator relations and kinase-substrate relations, a dendrogram of kinases can be constructed to monitor its abnormality. The results show that, on the dendrogram, the distribution of kinases demonstrated complex kinase activity changes and certain rules that occur during heart failure. Finally, we also identified the hub kinases in heart failure and verified the expression of these kinases by reverse-transcription polymerase chain reaction and Western blot analysis. In conclusion, for the first time, we have systematically analyzed the differences in kinases during heart failure and provided an unprecedented breadth of multi-omics data. These results can bring about a sufficient data foundation and novel research perspectives.

The effect of female sex hormones on Hsp27 phosphorylation and histological changes in prefrontal cortex after tMCAO

BACKGROUND

Female sex hormones are protective factors against many neurological disorders such as brain ischemia. Heat shock protein like HSP27 is activated after tissue injury. The main purpose of the present study is to determine the effect of a combined estrogen / progesterone cocktail on the morphology of astrocytes, neurons and Hsp27 phosphorylation after cerebral ischemia.

METHODS

One hour after the MCAO induction, a single dose of estrogen and progesterone was injected. The infarct volume was calculated by TTC staining 24 h after ischemia. Immunohistochemistry was used to show the effects of estrogen and progesterone on astrocyte and neuron morphology, as well as the Western blot technique used for the quantitation of phosphorylated Hsp27.

RESULTS

The combined dose of estrogen and progesterone significantly decreased astrocytosis after ischemia and increased neuron survival. There was a large increase in Hsp27 phosphorylation in the penumbra ischemic region after stroke, which was significantly reduced by hormone therapy.

CONCLUSION

Our results indicate that the neuroprotective effect of neurosteroids in the brain may be due to the modulation of heat shock proteins.

The Anticancer Effects of Flavonoids through miRNAs Modulations in Triple-Negative Breast Cancer

Triple- negative breast cancer (TNBC) incidence rate has regularly risen over the last decades and is expected to increase in the future. Finding novel treatment options with minimum or no toxicity is of great importance in treating or preventing TNBC. Flavonoids are new attractive molecules that might fulfill this promising therapeutic option. Flavonoids have shown many biological activities, including antioxidant, anti-inflammatory, and anticancer effects. In addition to their anticancer effects by arresting the cell cycle, inducing apoptosis, and suppressing cancer cell proliferation, flavonoids can modulate non-coding microRNAs (miRNAs) function. Several preclinical and epidemiological studies indicate the possible therapeutic potential of these compounds. Flavonoids display a unique ability to change miRNAs' levels via different mechanisms, either by suppressing oncogenic miRNAs or activating oncosuppressor miRNAs or affecting transcriptional, epigenetic miRNA processing in TNBC. Flavonoids are not only involved in the regulation of miRNA-mediated cancer initiation, growth, proliferation, differentiation, invasion, metastasis, and epithelial-to-mesenchymal transition (EMT), but also control miRNAs-mediated biological processes that significantly impact TNBC, such as cell cycle, immune system, mitochondrial dysregulation, modulating signaling pathways, inflammation, and angiogenesis. In this review, we highlighted the role of miRNAs in TNBC cancer progression and the effect of flavonoids on miRNA regulation, emphasizing their anticipated role in the prevention and treatment of TNBC.

Downregulation of ZNF395 Drives Progression of Pancreatic Ductal Adenocarcinoma through Enhancement of Growth Potential

BACKGROUND

Progression of pancreatic intraepithelial neoplasia (PanIN) to invasive carcinoma is a critical factor impacting the prognosis of patients with pancreatic tumors. However, the molecular mechanisms involved are not fully understood. We have reported that the process frequently involves loss of chromosome 8p, causing downregulation of DUSP4, thus conferring invasive ability on cancer cells. Here, we focus on ZNF395, whose expression was also found to be decreased by 8p loss and was predicted to be a growth suppressor gene.

METHODS

Pancreatic cancer cell lines inducibly expressing ZNF395 were established to assess the functional significance of ZNF395 in pancreatic carcinogenesis. Immunohistochemistry was also performed to analyze the expression levels of ZNF395 in pancreatic cancer tissues.

RESULTS

Induction of ZNF395 in pancreatic cancer cells resulted in marked activation of JNK and suppression of their proliferation through a delay in cell cycle progression. Immunohistochemistry revealed that ZNF395 was expressed ubiquitously in both normal pancreatic ducts and PanINs but was significantly reduced in invasive cancers, especially those showing poor differentiation.

CONCLUSION

ZNF395 acts as a novel tumor suppressor gene. Its downregulation caused by 8p loss in intraepithelial cells accelerates their proliferation through dysregulation of the cell cycle, leading to progression to invasive cancer.

The p38MAPK-MK2 Signaling Axis as a Critical Link Between Inflammation and Synaptic Transmission

p38 is a mitogen-activated protein kinase (MAPK), that responds primarily to stress stimuli. p38 has a number of targets for phosphorylation, including MAPK-activated protein kinase 2 (MK2). MK2 primarily functions as a master regulator of RNA-binding proteins, indirectly controlling gene expression at the level of translation. The role of MK2 in regulating the synthesis of pro-inflammatory cytokines downstream of inflammation and cellular stress is well-described. A significant amount of evidence, however, now points to a role for the p38^MAPK-MK2 signaling axis in mediating synaptic plasticity through control of AMPA receptor trafficking and the morphology of dendritic spines. These processes are mediated through control of cytoskeletal dynamics via the activation of cofilin-1 and possibly control of the expression of Arc/Arg3.1. There is evidence that MK2 is necessary for group I metabotropic glutamate receptors long-term depression (mGluR-LTD). Disruption of this signaling may play an important role in mediating cognitive dysfunction in neurological disorders such as fragile X syndrome and Alzheimer’s disease. To date, the role of neuronal MK2 mediating synaptic plasticity in response to inflammatory stimuli has not yet been investigated. In immune cells, it is clear that MK2 is phosphorylated following activation of a broad range of cell surface receptors for cytokines and other inflammatory mediators. We propose that neuronal MK2 may be an important player in the link between inflammatory states and dysregulation of synaptic plasticity underlying cognitive functions. Finally, we discuss the potential of the p38^MAPK-MK2 signaling axis as target for therapeutic intervention in a number of neurological disorders.

Diversity and versatility of p38 kinase signalling in health and disease

The ability of cells to deal with different types of stressful situations in a precise and coordinated manner is key for survival and involves various signalling networks. Over the past 25 years, p38 kinases — in particular, p38α — have been implicated in the cellular response to stress at many levels. These span from environmental and intracellular stresses, such as hyperosmolarity, oxidative stress or DNA damage, to physiological situations that involve important cellular changes such as differentiation. Given that p38α controls a plethora of functions, dysregulation of this pathway has been linked to diseases such as inflammation, immune disorders or cancer, suggesting the possibility that targeting p38α could be of therapeutic interest. In this Review, we discuss the organization of this signalling pathway focusing on the diversity of p38α substrates, their mechanisms and their links to particular cellular functions. We then address how the different cellular responses can be generated depending on the signal received and the cell type, and highlight the roles of this kinase in human physiology and in pathological contexts.

p38α — the best-characterized member of the p38 kinase family — is a key mediator of cellular stress responses. p38α is activated by a plethora of signals and functions through a multitude of substrates to regulate different cellular behaviours. Understanding context-dependent p38α signalling provides important insights into p38α roles in physiology and pathology.

The Two Sides of the Same Coin-Influenza Virus and Intracellular Signal Transduction

Cells respond to extracellular agents by activation of intracellular signaling pathways. Viruses can be regarded as such agents, leading to a firework of signaling inside the cell, primarily induced by pathogen-associated molecular patterns (PAMPs) that provoke safeguard mechanisms to defend from the invader. In the constant arms race between pathogen and cellular defense, viruses not only have evolved mechanisms to suppress or misuse supposedly antiviral signaling processes for their own benefit but also actively induce signaling to promote replication. This creates viral dependencies that may be exploited for novel strategies of antiviral intervention. Here, we will summarize the current knowledge of activation and function of influenza virus-induced signaling pathways with a focus on nuclear factor (NF)-κB signaling, mitogen-activated protein kinase cascades, and the phosphatidylinositol-3-kinase pathway. We will discuss the opportunities and drawbacks of targeting these signaling pathways for antiviral intervention.

Combination of Mesenchymal Stem Cell and Endothelial Progenitor Cell Infusion Accelerates Injured Intestinal Repair by Regulating Gut Microbiota after Hematopoietic Cell Transplantation

Mesenchymal stem cells (MSC) have been widely applied for repairing intestinal barrier function and restoring immune homeostasis for pretransplantation conditioning, yet the repair process is often impaired or delayed owing to a lack of vascularity. How combined therapy with MSC and endothelial progenitor cells (EPC) for the intestinal microenvironment and repair remain unclear. In this study, BALB/c mice received syngeneic bone marrow transplantation with or without MSC or EPC infusion. The findings show that the MSC+EPC mice had greater blood capillary distribution and higher expression of tight junction protein (occludin) in the small intestinal tract. Meanwhile, the MSC+EPC cotreatment increased IL-17A levels and decreased IFN-γ levels at the early stage after transplantation. Furthermore, the MSC+EPC treatment motivated p38 mitogen-activated protein kinase (MAPK) and enhanced heat shock protein 27 (HSP27) activation, which subsequently promoted intestinal epithelial cell proliferation and down-regulated apoptosis-related molecule caspase 3 expression. Finally, the high-throughput sequencing of gut microbiota (16S) showed that the MSC+EPC treatment can inhibit the Enterococcus population (<0.5%) and stabilize the Akkermansia population (~15%), with the Akkermansia population showing significant positive correlations with p38 MAPK/phos-p38, HSP27/phos-HSP27, IL-17A, and occludin. Taken together, our results show that MSC+EPC combined therapy is beneficial for the repair of injured intestine and drives gut microbial community stability by regulating the intestinal microenvironment.

Canonical and noncanonical TGF-β signaling regulate fibrous tissue differentiation in the axial skeleton

Previously, we showed that embryonic deletion of TGF-β type 2 receptor in mouse sclerotome resulted in defects in fibrous connective tissues in the spine. Here we investigated how TGF-β regulates expression of fibrous markers: Scleraxis, Fibromodulin and Adamtsl2. We showed that TGF-β stimulated expression of Scleraxis mRNA by 2 h and Fibromodulin and Adamtsl2 mRNAs by 8 h of treatment. Regulation of Scleraxis by TGF-β did not require new protein synthesis; however, protein synthesis was required for expression of Fibromodulin and Adamtsl2 indicating the necessity of an intermediate. We subsequently showed Scleraxis was a potential intermediate for TGF-β-regulated expression of Fibromodulin and Adamtsl2. The canonical effector Smad3 was not necessary for TGF-β-mediated regulation of Scleraxis. Smad3 was necessary for regulation of Fibromodulin and Adamtsl2, but not sufficient to super-induce expression with TGF-β treatment. Next, the role of several noncanonical TGF-β pathways were tested. We found that ERK1/2 was activated by TGF-β and required to regulate expression of Scleraxis, Fibromodulin, and Adamtsl2. Based on these results, we propose a model in which TGF-β regulates Scleraxis via ERK1/2 and then Scleraxis and Smad3 cooperate to regulate Fibromodulin and Adamtsl2. These results define a novel signaling mechanism for TGFβ-mediated fibrous differentiation in sclerotome.

p38 MAPK Pathway in the Heart: New Insights in Health and Disease

The p38 mitogen-activated kinase (MAPK) family controls cell adaptation to stress stimuli. p38 function has been studied in depth in relation to cardiac development and function. The first isoform demonstrated to play an important role in cardiac development was p38α; however, all p38 family members are now known to collaborate in different aspects of cardiomyocyte differentiation and growth. p38 family members have been proposed to have protective and deleterious actions in the stressed myocardium, with the outcome of their action in part dependent on the model system under study and the identity of the activated p38 family member. Most studies to date have been performed with inhibitors that are not isoform-specific, and, consequently, knowledge remains very limited about how the different p38s control cardiac physiology and respond to cardiac stress. In this review, we summarize the current understanding of the role of the p38 pathway in cardiac physiology and discuss recent advances in the field.

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.

Unpuzzling COVID-19: tissue-related signaling pathways associated with SARS-CoV-2 infection and transmission

The highly infective coronavirus disease 19 (COVID-19) is caused by a novel strain of coronaviruses - the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) - discovered in December 2019 in the city of Wuhan (Hubei Province, China). Remarkably, COVID-19 has rapidly spread across all continents and turned into a public health emergency, which was ultimately declared as a pandemic by the World Health Organization (WHO) in early 2020. SARS-CoV-2 presents similar aspects to other members of the coronavirus family, mainly regarding its genome, protein structure and intracellular mechanisms, that may translate into mild (or even asymptomatic) to severe infectious conditions. Although the mechanistic features underlying the COVID-19 progression have not been fully clarified, current evidence have suggested that SARS-CoV-2 may primarily behave as other β-coronavirus members. To better understand the development and transmission of COVID-19, unveiling the signaling pathways that may be impacted by SARS-CoV-2 infection, at the molecular and cellular levels, is of crucial importance. In this review, we present the main aspects related to the origin, classification, etiology and clinical impact of SARS-CoV-2. Specifically, here we describe the potential mechanisms of cellular interaction and signaling pathways, elicited by functional receptors, in major targeted tissues/organs from the respiratory, gastrointestinal (GI), cardiovascular, renal, and nervous systems. Furthermore, the potential involvement of these signaling pathways in evoking the onset and progression of COVID-19 symptoms in these organ systems are presently discussed. A brief description of future perspectives related to potential COVID-19 treatments is also highlighted.