Mechanisms and functions of p38 MAPK signalling. Biochem J. 2010;429:403-417. [PMID: 20626350 DOI: 10.1042/bj20100323]

Toxicological impacts of excessive lithium on largemouth bass (Micropterus salmoides): Body weight, hepatic lipid accumulation, antioxidant defense and inflammation response

The unreasonably anthropogenic activities make lithium a widespread pollutant in aquatic environment, and this metallic element can enter the food chain to influence humans. Therefore, the study was designed to explore the influence of dietary lithium supplementation on body weight, lipid deposition, antioxidant capacity and inflammation response of largemouth bass. Multivariate statistical analysis confirmed the toxicological impacts of excessive lithium on largemouth bass. Specifically, excessive dietary lithium (≥87.08 mg/kg) significantly elevated weight gain and feed intake of largemouth bass. Meanwhile, overload lithium inclusion aggravated the accumulation of hepatic lipid and serum lithium. Gene expression results showed that lithium inclusion, especially overload lithium, promoted the transcription of lipogenesis related genes, PPARγ, ACC and FAS, inhibited the expression of fatty acid oxidation related genes, PPARα and ACO, and lipolysis related genes, HSL and MGL. Meanwhile, high lithium inclusion caused the oxidative stress, which was partly through the inhibition of Nrf2/Keap1 pathway. Moreover, dietary lithium inclusion significantly depressed the activity of hepatic lysozyme, and promoted the transcription of proinflammation factors, TNF-α, 5-LOX, IL-1β and IL-8, which was suggested to be regulated by the p38 MAPK pathway. Our findings suggested that overload lithium resulted in increased body weight, hepatic lipid deposition, oxidative stress and inflammation response. The results obtained here provided novel insights on the toxicological impacts of excessive lithium on aquatic animals.

Recent clinical findings on the role of kinase inhibitors in COVID-19 management

The highly pathogenic, novel coronavirus disease (COVID-19) outbreak has emerged as a once-in-a-century pandemic with poor consequences, urgently calling for new therapeutics, cures, and supportive interventions. It has already affected over 250 million people worldwide; thereby, there is a need for novel therapies to alleviate the related complications. There is a paradigm shift in developing drugs and clinical practices to combat COVID-19. Several clinical trials have been performed or are testing diverse pharmacological interventions to alleviate viral load and complications such as cytokine release storm (CRS). Kinase-inhibitors have appeared as potential antiviral agents for COVID-19 patients due to their efficacy against CRS. Combination of kinase inhibitors with other therapies can achieve more efficacy against COVID-19. Based on the pre-clinical trials, kinase inhibitors such as Janus kinase-signal transducer and activator of transcription (JAK/STAT) inhibitors, Brutton's tyrosin kinase (BTK) inhibitors, p38 mitogen-activated protein kinases (p38 MAPK) inhibitors, Glycogen synthase kinase 3 (GSK-3) inhibitors can be a promising strategy against COVID-19. Kinase inhibitors possess crucial pharmacological properties for a successful re-purposing in terms of dual anti-inflammatory and anti-viral effects. This review will address the current clinical evidence and the newest discovery regarding the application of kinase inhibitors in COVID-19. An outlook on ongoing clinical trials (clinicaltrials.gov) and unpublished data is also presented here. Besides, Kinase inhibitors' function on COVID-19-mediated CRS is discussed.

HSF2BP protects against acute liver injury by regulating HSF2/HSP70/MAPK signaling in mice

Heat shock proteins (HSPs) depletion and protein misfolding are important causes of hepatocyte death and liver regeneration disorder in liver injury. HSF2BP, as its name implies, is a binding protein of HSF2, but the specific role of HSF2BP in heat shock response (HSR) remains unknown. The aim of this study is to identify the role of HSF2BP in HSR and acute liver injury. In this study, we found that HSF2BP expression increased significantly within 24 h after APAP administration, and the trend was highly consistent with that of HSP70. hsf2bp-KO and hsf2bp-TG mouse models demonstrated HSF2BP reduced hepatocyte death, ameliorated inflammation, and improved liver function in APAP- or D-GalN/LPS- induced liver injury. Meanwhile, a significant increase of the survival rate was observed in hsf2bp-TG mice after APAP administration. Further studies showed that HSF2BP upregulated the expression of HSF2 and HSP70 and inhibited the activation of Jnk1/2 and P38 MAPK. Additionally, HSP70 siRNA pretreatment abolished the effect of HSF2BP on the MAPK pathway in APAP-treated hepatocytes. The results reveal that HSF2BP is a protective factor in acute liver injury, and the HSF2BP/HSP70/MAPK regulatory axis is crucial for the pathogenesis of liver injury. HSF2BP is a potential therapeutic target for liver injury.

Effectiveness and Mechanisms of Low-Intensity Pulsed Ultrasound on Osseointegration of Dental Implants and Biological Functions of Bone Marrow Mesenchymal Stem Cells

Dental implant restoration is the preferred choice for patients with dentition defects or edentulous patients, and obtaining stable osseointegration is the determining factor for successful implant healing. The risk of implant failure during the healing stage is still an urgent problem in clinical practice due to differences in bone quality at different implant sites and the impact of some systemic diseases on bone tissue metabolism. Low-intensity pulsed ultrasound (LIPUS) is a noninvasive physical intervention method widely recognized in the treatment of bone fracture and joint damage repair. Moreover, many studies indicated that LIPUS could effectively promote the osseointegration of dental implants and improve the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). This review is aimed at investigating the research progress on the use of LIPUS in dental implant medicine from three aspects: (1) discuss the promoting effects of LIPUS on osseointegration and peri-implant bone regeneration, (2) summarize the effects and associated mechanisms of LIPUS on the biological functions of BMSCs, and (3) introduce the application and prospects of LIPUS in the clinical work of dental implantation. Although many challenges need to be overcome in the future, LIPUS is bound to be an efficient and convenient therapeutic method to improve the dental implantation success rate and expand clinical implant indications.

Regulation of Claspin by the p38 stress-activated protein kinase protects cells from DNA damage

Stress-activated protein kinases (SAPKs) enhance survival in response to environmental changes. In yeast, the Hog1 SAPK and Mrc1, a protein required for DNA replication, define a safeguard mechanism that allows eukaryotic cells to prevent genomic instability upon stress during S-phase. Here we show that, in mammals, the p38 SAPK and Claspin-the functional homolog of Mrc1-protect cells from DNA damage upon osmostress during S-phase. We demonstrate that p38 phosphorylates Claspin and either the mutation of the p38-phosphorylation sites in Claspin or p38 inhibition suppresses the protective role of Claspin on DNA damage. In addition, wild-type Claspin but not the p38-unphosphorylatable mutant has a protective effect on cell survival in response to cisplatin treatment. These findings reveal a role of Claspin in response to chemotherapeutic drugs. Thus, this pathway protects S-phase integrity from different insults and it is conserved from yeast to mammals.

Myricetin inhibits pseudorabies virus infection through direct inactivation and activating host antiviral defense

Myricetin, a polyhydroxyflavone compound, is one of the main ingredients of various human foods and therefore also known as dietary flavonoids. Due to the continuous emergence of resistant strains of herpesviruses, novel control measures are required. In the present study, myricetin exhibited potent antiviral activity against pseudorabies virus (PRV), a model organism of herpesvirus. The suppression rate could reach up to 96.4% at a concentration of 500 μM in cells, and the 50% inhibitory concentration (IC₅₀) was 42.69 μM. Moreover, the inhibitory activity was not attenuated by the increased amount of infective dose, and a significant reduction of intracellular PRV virions was observed by indirect immunofluorescence. A mode of action study indicated that myricetin could directly inactivate the virus in vitro, leading to inhibition of viral adsorption, penetration and replication in cells. In addition to direct killing effect, myricetin could also activate host antiviral defense through regulation of apoptosis-related gene expressions (Bcl-2, Bcl-xl, Bax), NF-κB and MAPK signaling pathways and cytokine gene expressions (IL-1α, IL-1β, IL-6, c-Jun, STAT1, c-Fos, and c-Myc). In PRV-infected mouse model, myricetin could enhance the survival rate by 40% at 5 days post infection, and viral loads in kidney, liver, lung, spleen, and brain were significantly decreased. The pathological changes caused by PRV infection were improved by myricetin treatment. The gene expressions of inflammatory factors (MCP-1, G-CSF, IL-1α, IL-1β, and IL-6) and apoptotic factors (Bcl-xl, Bcl-2, and Bax) were regulated by myricetin in PRV-infected mice. The present findings suggest that myricetin can effectively inhibit PRV infection and become a candidate for development of new anti-herpesvirus drugs.

Recent Advances in PROTACs for Drug Targeted Protein Research

Proteolysis-targeting chimera (PROTAC) is a heterobifunctional molecule. Typically, PROTAC consists of two terminals which are the ligand of the protein of interest (POI) and the specific ligand of E3 ubiquitin ligase, respectively, via a suitable linker. PROTAC degradation of the target protein is performed through the ubiquitin–proteasome system (UPS). The general process is that PROTAC binds to the target protein and E3 ligase to form a ternary complex and label the target protein with ubiquitination. The ubiquitinated protein is recognized and degraded by the proteasome in the cell. At present, PROTAC, as a new type of drug, has been developed to degrade a variety of cancer target proteins and other disease target proteins, and has shown good curative effects on a variety of diseases. For example, PROTACs targeting AR, BR, BTK, Tau, IRAK4, and other proteins have shown unprecedented clinical efficacy in cancers, neurodegenerative diseases, inflammations, and other fields. Recently, PROTAC has entered a phase of rapid development, opening a new field for biomedical research and development. This paper reviews the various fields of targeted protein degradation by PROTAC in recent years and summarizes and prospects the hot targets and indications of PROTAC.

A perspective on molecular signalling dysfunction, its clinical relevance and therapeutics in autism spectrum disorder

Intellectual disability (ID) and autism spectrum disorder (ASD) are neurodevelopmental disorders that have become a primary clinical and social concern, with a prevalence of 2-3% in the population. Neuronal function and behaviour undergo significant malleability during the critical period of development that is found to be impaired in ID/ASD. Human genome sequencing studies have revealed many genetic variations associated with ASD/ID that are further verified by many approaches, including many mouse and other models. These models have facilitated the identification of fundamental mechanisms underlying the pathogenesis of ASD/ID, and several studies have proposed converging molecular pathways in ASD/ID. However, linking the mechanisms of the pathogenic genes and their molecular characteristics that lead to ID/ASD has progressed slowly, hampering the development of potential therapeutic strategies. This review discusses the possibility of recognising the common molecular causes for most ASD/ID based on studies from the available models that may enable a better therapeutic strategy to treat ID/ASD. We also reviewed the potential biomarkers to detect ASD/ID at early stages that may aid in diagnosis and initiating medical treatment, the concerns with drug failure in clinical trials, and developing therapeutic strategies that can be applied beyond a particular mutation associated with ASD/ID.

The impact of Nrf2/HO-1, caspase-3/Bax/Bcl2 and ATF6/IRE1/PERK/GRP78 signaling pathways in the ameliorative effects of morin against methotrexate-induced testicular toxicity in rats

BACKGROUND

Methotrexate (MT) is a broadly used chemotherapeutic drug however its clinical use is confronted with several forms of toxicities containing testicular damage. The current study assessed the ameliorative effects of morin on MT-induced testicular damage with the investigation of its mechanism and the potential involvement of oxidative stress, inflammation, apoptosis and endoplasmic reticulum stress in such protection.

METHODS

The animals were divided into 5 distinct groups (7 rats in each group). Group 1 was control group, group 2 received MT-only (20 mg/kg bw), group 3 received orally morin-only (100 mg/kg bw), group 4 received MT (20 mg/kg bw) + morin (50 mg/kg bw) and group 5 received MT (20 mg/kg bw) + morin (100 mg/kg). In this study, morin was administered orally for 10 days, while MT was administered intraperitoneally on the 5th day.

RESULTS

MT intoxication was linked with augmented MDA while decreased GSH levels, the enzyme activities of glutathione peroxidase, superoxide dismutase, and catalase and mRNA levels of HO-1 and Nrf2 in the testis tissues. MT injection caused inflammation in the testicular tissue via up-regulation of MAPK14, NFκB, TNF-α and IL-1β. MT application also caused apoptosis and endoplasmic reticulum stress in the testis tissue via increasing mRNA transcript levels of Bax, caspase-3, PERK, IRE1, ATF-6, GRP78 and down-regulation of Bcl-2.

CONCLUSION

Treatment with morin at a dose of 50 and 100 mg/kg considerably mitigated oxidative stress, inflammation, apoptosis and endoplasmic reticulum stress in the testicular tissue indicating that testicular damage related to MT toxicity could be modulated by morin administration.

Inflammatory pathways in COVID‐19: Mechanism and therapeutic interventions

The 2019 coronavirus disease (COVID‐19) pandemic has become a global crisis. In the immunopathogenesis of COVID‐19, SARS‐CoV‐2 infection induces an excessive inflammatory response in patients, causing an inflammatory cytokine storm in severe cases. Cytokine storm leads to acute respiratory distress syndrome, pulmonary and other multiorgan failure, which is an important cause of COVID‐19 progression and even death. Among them, activation of inflammatory pathways is a major factor in generating cytokine storms and causing dysregulated immune responses, which is closely related to the severity of viral infection. Therefore, elucidation of the inflammatory signaling pathway of SARS‐CoV‐2 is important in providing otential therapeutic targets and treatment strategies against COVID‐19. Here, we discuss the major inflammatory pathways in the pathogenesis of COVID‐19, including induction, function, and downstream signaling, as well as existing and potential interventions targeting these cytokines or related signaling pathways. We believe that a comprehensive understanding of the regulatory pathways of COVID‐19 immune dysregulation and inflammation will help develop better clinical therapy strategies to effectively control inflammatory diseases, such as COVID‐19.

Multi-stage virtual screening of natural products against p38α mitogen-activated protein kinase: predictive modeling by machine learning, docking study and molecular dynamics simulation

p38α is a mitogen-activated protein kinase (MAPK), and the signaling pathways involved are closely related to the inflammation, apoptosis and differentiation of cells, which also makes it an attractive target for drug discovery. With the high efficiency and low cost, virtual screening technology is becoming an indispensable part of drug development. In this study, a novel multi-stage virtual screening method based on machine learning, molecular docking and molecular dynamics simulation was developed to identify p38α MAPK inhibitors from natural products in ZINC database, which improves the prediction accuracy by considering and utilizing both ligand and receptor information compared to any individual approach. Ultimately, we screened out two candidate inhibitors with acceptable ADMET properties (ZINC4260400 and ZINC8300300). Among the generated machine learning models, Random Forest (RF) and Support Vector Machine (SVM) performed better, with the area under the receiver operating characteristic curve (AUC) values of 0.932 and 0.931 on the test set, as well as 0.834 and 0.850 on the external validation set. In addition, the results of molecular docking and ADMET prediction showed that two compounds with appropriate pharmacokinetic properties had binding free energies less than −8.0 kcal/mol for the target protein, and the results of molecular dynamics simulations further confirmed that they were stable during the process of inhibition.

Antinociceptive properties of losmapimod in two acute pain models in rats: behavioural analysis, immunohistochemistry, dose response, and comparison with usual analgesic drugs

Background

The p38 protein is a ubiquitous mitogen-activated protein kinase involved in the proinflammatory signalling pathway and in the pain response after various noxious stimuli. Many p38 inhibitors have been developed and shown to provide effective analgesia in animal models. They are, however, mainly administered intrathecally or intravenously. Our study aimed to evaluate losmapimod, a novel oral p38 inhibitor, in two murine acute pain models.

Methods

Losmapimod (12 mg kg-1) was compared with paracetamol, ketamine, and morphine using thermal and mechanical stimulation after carrageenan injection. A dose-effect study was also performed with this model. Behavioural testing was also performed in a plantar incision model to confirm the analgesic effect of losmapimod. Expression of activated p38 in neurones, microglia, and astrocytes was also investigated at 2, 15, and 24 h after carrageenan injection.

Results

Losmapimod was both antiallodynic and antihyperalgesic in the carrageenan pain model and provided an antinociceptive effect similar to that of morphine. The dose of 12 mg kg-1 was shown to be the ED78 and ED64 after thermal and mechanical stimulation, respectively. After plantar incision, losmapimod provided a significant antinociceptive effect. No life-threatening side-effect was observed in the behavioural study. Losmapimod prevented neurone and microglial activation at 2 and 15 h after carrageenan injection, respectively, but no effect was found on astrocytic activation.

Conclusion

Losmapimod appears to be a promising drug in severe acute pain conditions. Losmapimod could also be helpful for postoperative pain control, as suggested by its effect after plantar incision.

Deciphering the combination mechanisms of Gualou–Xiebai herb pair against atherosclerosis by network pharmacology and HPLC-Q-TOF-MS technology

Introduction: Gualou (Trichosanthes kirilowii Maxim)–Xiebai (Allium macrostemon Bunge) (GLXB) is a well-known herb pair against atherosclerosis (AS). However, the combination mechanisms of GLXB herb pair against AS remain unclear.

Objective: To compare the difference in efficacy between GLXB herb pair and the single herbs and to explore the combination mechanisms of GLXB against AS in terms of compounds, targets, and signaling pathways.

Methods: The combined effects of GLXB were evaluated in AS mice. The main compounds of GLXB were identified via quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS) and UNIFI informatics platforms. The united mechanisms of GLXB in terms of nodes, key interactions, and functional clusters were realized by network pharmacology. At last, the anti-atherosclerotic mechanisms of GLXB were validated using enzyme-linked immunosorbent assay (ELISA) and Western blot in AS mice.

Results: The anti-atherosclerotic effects of the GLXB herb pair (6 g/kg) were more significant than those of Gualou (4 g/kg) and Xiebai (2 g/kg) alone. From the GLXB herb pair, 48 main components were identified. In addition, the GLXB herb pair handled more anti-atherosclerotic targets and more signaling pathways than Gualou or Xiebai alone, whereas 10 key targets of GLXB were found using topological analysis. Furthermore, the GLXB herb pair (6 g/kg) could suppress the inflammatory target levels of IL-6, IL-1β, TNF-α, ALOX5, PTGS2, and p-p38 in AS mice. GLXB herb pair (6 g/kg) could also ameliorate endothelial growth and function by regulating the levels of VEGFA, eNOS, p-AKT, VCAM-1, and ICAM-1 and reducing macrophage adhesion to vascular wall in AS mice. GLXB herb pair (6 g/kg) could improve the blood lipid levels in AS mice. In addition, the regulating effects of GLXB herb pair (6 g/kg) on levels of IL-1β, TNF-α, ALOX5, VEGFA, eNOS, VCAM-1, ICAM-1, and blood lipids were more significant than those of Gualou (4 g/kg) or Xiebai alone (2 g/kg).

Conclusion: The combination mechanisms of the GLXB herb pair were elucidated in terms of components, targets, and signaling pathways, which may be related to suppressing inflammation, regulating vascular endothelial growth/function, and improving blood lipid levels.

Role of p38 MAPK Signalling in Testis Development and Male Fertility

The testis is an important male reproductive organ, which ensures reproductive function via the secretion of testosterone and the generation of spermatozoa. Testis development begins in the embryonic period, continues after birth, and generally reaches functional maturation at puberty. The stress-activated kinase, p38 mitogen-activated protein kinase (MAPK), regulates multiple cell processes including proliferation, differentiation, apoptosis, and cellular stress responses. p38 MAPK signalling plays a crucial role in testis development by regulating spermatogenesis, the fate determination of pre-Sertoli, and primordial germ cells during embryogenesis, the proliferation of testicular cells in the postnatal period, and the functions of mature Sertoli and Leydig cells. In addition, p38 MAPK signalling is involved in decreased male fertility when exposed to various harmful stimuli. This review will describe in detail the biological functions of p38 MAPK signalling in testis development and male reproduction, together with its pathological role in male infertility.

Resistance evolution against host-directed antiviral agents: Buffalopox virus switches to use p38-ϒ under long-term selective pressure of an inhibitor targeting p38-α

Host-dependency factors have increasingly been targeted to minimize antiviral drug resistance. In this study, we have demonstrated that inhibition of p38 mitogen-activated protein kinase (a cellular protein) suppresses buffalopox virus (BPXV) protein synthesis by targeting p38-MNK1-eIF4E signaling pathway. In order to provide insights into the evolution of drug resistance, we selected resistant mutants by long-term sequential passages (P; n = 60) in the presence of p38 inhibitor (SB239063). The P60-SB239063 virus exhibited significant resistance to SB239063 as compared to the P60-Control virus. To provide mechanistic insights on the acquisition of resistance by BPXV-P60-SB239063, we generated p38-α and p38-ϒ (isoforms of p38) knockout Vero cells by CRISPR/Cas9-mediated genome editing. It was demonstrated that unlike the wild type (WT) virus which is dependent on p38-α isoform, the resistant virus (BPXV-P60-SB239063) switches over to use p38-ϒ so as to efficiently replicate in the target cells. This is a rare evidence wherein a virus was shown to bypass the dependency on a critical cellular factor under selective pressure of a drug.

GFAT1-linked TAB1 glutamylation sustains p38 MAPK activation and promotes lung cancer cell survival under glucose starvation

Reprogrammed cell metabolism is deemed as one of the hallmarks of cancer. Hexosamine biosynthesis pathway (HBP) acts as an “energy sensor” in cells to regulate metabolic fluxes. Glutamine-fructose-6-phosphate amidotransferase 1 (GFAT1), the rate-limiting enzyme of HBP, is broadly found with elevated expression in human cancers though its exact and concrete role in tumorigenesis still remains unknown and needs further investigation. P38 mitogen-activated protein kinase (MAPK) is an important component of stress-signaling pathway and plays a critical role in cell fate decision, whereas the underlying mechanism of its activation under nutrient stress also remains elusive. In this study, we show that glucose deprivation induces the interaction of GFAT1 with transforming growth factor β-activated kinase 1 binding protein 1 (TAB1) in a TAB1 S438 phosphorylation-dependent manner. Subsequently, the binding of GFAT1 to TAB1 facilitates TTLL5–GFAT1–TAB1 complex formation, and the metabolic activity of GFAT1 for glutamate production further contributes to TTLL5-mediated TAB1 glutamylation. In consequence, TAB1 glutamylation promotes the recruitment of p38α MAPK and thus drives p38 MAPK activation. Physiologically, GFAT1-TAB1-p38 signaling promotes autophagy occurrence and thus protects tumor cell survival under glucose deficiency. Clinical analysis indicates that both GFAT1 and TAB1 S438 phosphorylation levels correlate with the poor prognosis of lung adenocarcinoma patients. These findings altogether uncover an unidentified mechanism underlying p38 MAPK signaling regulation by metabolic enzyme upon nutrient stress and provide theoretical rationality of targeting GFAT1 for cancer treatment.

P38α MAPK is a gatekeeper of uterine progesterone responsiveness at peri-implantation via Ube3c-mediated PGR degradation

Estrogen and progesterone specify the establishment of uterine receptivity mainly through their respective nuclear receptors, ER and PR. PR is transcriptionally induced by estrogen-ER signaling in the endometrium, but how the protein homeostasis of PR in the endometrium is regulated remains elusive. Here, we demonstrated that the uterine-selective depletion of P38α derails normal uterine receptivity ascribed to the dramatic down-regulation of PR protein and disordered progesterone responsiveness in the uterine stromal compartment, leading to defective implantation and female infertility. Specifically, Ube3c, an HECT family E3 ubiquitin ligase, targets PR for polyubiquitination and thus proteasome degradation in the absence of P38α. Moreover, we discovered that P38α restrains the polyubiquitination activity of Ube3c toward PR by phosphorylating the Ube3c at serine741 . In summary, we provided genetic evidence for the regulation of PR protein stability in the endometrium by P38α and identified Ube3c, whose activity was modulated by P38α-mediated phosphorylation, as an E3 ubiquitin ligase for PR in the uterus.

Targeting DUSP Activity as a Treatment for High-Grade Serous Ovarian Carcinoma

Identifying novel, durable treatments for high-grade serous ovarian cancer (HGSOC) is paramount to extend both progression-free survival (PFS) and overall survival (OS) in patients afflicted with this disease. Dual-specificity phosphatase 1 (DUSP1) was identified as one of seven genes that may significantly affect prognosis in patients with HGSOC; however, the role of DUSP inhibition (DUSPi) in the treatment of HGSOC remains largely unknown. In this study, we show that DUSP1 is highly expressed in HGSOC and confers worse PFS and OS. Further, we corroborate data that show DUSP1 expression is directly associated with therapy resistance. Using a tissue microarray of 137 different serous ovarian carcinomas, we demonstrate the high expression of DUSP1 in primary and recurrent serous ovarian cancer. In both acquired and de novo therapy HGSOC-resistant models, DUSPi both inhibited cellular proliferation and promoted cell death. RPPA analysis of HGSOC cells revealed DUSPi led to the differential regulation of several pathways, including AMPK and mTORC. Further, in a patient-derived xenograft HGSOC model, DUSPi significantly inhibited tumor progression.

Pan-Cancer Analysis Reveals SH3TC2 as an Oncogene for Colorectal Cancer and Promotes Tumorigenesis via the MAPK Pathway

Simple Summary

SH3 domain and tetrapeptide repeat 2 (SH3TC2) is a protein-encoding gene and has previously been described as a critical signaling hub for neurological disorders, but no systematic analysis of SH3TC2 is available in cancer research. We analyzed SH3TC2 in various kinds of cancer to find its tumorigenic role in one or more specific cancers and further explored the mechanism of SH3TC2 in colorectal cancer (CRC). Our research revealed that higher expression of SH3TC2 indicated poor disease-free survival and promoted CRC progression and invasion via the MAPK signaling pathway.

Abstract

SH3 domain and tetrapeptide repeat 2 (SH3TC2) is a protein-encoding gene and has previously been described as a critical signaling hub for neurological disorders. Although increasing evidence supports a vital role of SH3TC2 in the tumorigenesis of various kinds of cancer, no systematic analysis of SH3TC2 is available. The function and mechanism of SH3TC2 in other cancers remain unknown. Thus, this study aimed to analyze SH3TC2 in various kinds of cancer to find its tumorigenic role in one or more specific cancers. In the current study, we analyzed the expression level and prognostic value of SH3TC2 in different tumors in the TCGA-GTEx pan-cancer dataset. Subsequently, the prognostic role and mechanism of SH3TC2 in colorectal cancer (CRC) were further explored via clinical samples and in vitro and in vivo experiments. We observed differential expression of SH3TC2 in colon adenocarcinoma (COAD), acute myeloid leukemia (LAML), READ (rectum adenocarcinoma), SKCM (skin cutaneous melanoma), and TGCT (testicular germ cell tumors). Subsequently, SH3TC2 showed a significant effect on the clinical stage and prognostic value in CRC, LAML, and SKCM. Moreover, we found in the TCGA database and seven GEO datasets that SH3TC2 was significantly highly expressed in tumor tissue. Through enrichment analysis of SH3TC2 and its co-expressed genes, we found that SH3TC2 may play a role in the MAPK signaling pathway. Correlation analysis indicated that SH3TC2 was significantly associated with multiple key factors in the MAPK signaling pathway. Additionally, higher expression of SH3TC2 was found in tumor tissue in our cohort including 40 CRC patients. Overexpression of SH3TC2 may imply poor prognosis. Knockdown of SH3TC2 significantly inhibited tumor invasion, migration, and proliferation. More importantly, knockdown of SH3TC2 inhibited tumor growth in a CRC mouse model. The study preliminarily conducted a pan-cancer study of SH3TC2 and further explored the mechanism of SH3TC2 in CRC. Our research revealed that higher expression of SH3TC2 may promote CRC progression and invasion via the MAPK signaling pathway.

N-Acetylcysteine or Sodium Selenite Prevent the p38-Mediated Production of Proinflammatory Cytokines by Microglia during Exposure to Mercury (II)

Mercury (Hg) is known for its neurotoxicity and is reported to activate microglia cells at low exposure levels. Since mercury decreases the activity of the glutathione and thioredoxin systems, we hypothesize that Hg would, in turn, disrupt microglia homeostasis by interfering with redox regulation of signaling pathways. Thus, in this work, we analyzed the effect of exposure to Hg²⁺ on nuclear translocation and activation of NF-kB (p50) and p38 and pro-inflammatory gene transcription (IL-1ß; iNOS, TNF-alpha) considering the interaction of Hg with the glutathione system and thioredoxin systems in microglial cells. N9 (mouse) microglia cells were exposed to different concentrations of Hg²⁺ and the 24 h EC₅₀ for a reduction in viability was 42.1 ± 3.7 μM. Subsequent experiments showed that at sub-cytotoxic levels of Hg²⁺, there was a general increase in ROS (≈40%) accompanied by a significant depletion (60-90%) of glutathione (GSH) and thioredoxin reductase (TrxR) activity. Upon 6 h of exposure to Hg²⁺, p38 (but not p50) accumulated in the nucleus (50% higher than in control), which was accompanied by an increase in its phosphorylation. Transcript levels of both IL1-ß and iNOS were increased over two-fold relative to the control. Furthermore, pre-exposure of cells to the p38 inhibitor SB 239063 hindered the activation of cytokine transcription by Hg²⁺. These results show that disruption of redox systems by Hg²⁺ prompts the activation of p38 leading to transcription of pro-inflammatory genes in microglia cells. Treatment of N9 cells with NAC or sodium selenite-which caused an increase in basal GSH and TrxR levels, respectively, prevented the activation of p38 and the transcription of pro-inflammatory cytokines. This result demonstrates the importance of an adequate nutritional status to minimize the toxicity resulting from Hg exposure in human populations at risk.

Carnosine Synthase 1 Contributes to Interferon Gamma-Induced Arginine Depletion via Mitogen-activated Protein Kinase 11 Signaling in Bovine Mammary Epithelial Cells

Arginine is one of the host semiessential amino acids with diverse biological activities, and arginine depletion is associated with the incidence of many diseases. Arginine depletion induced by diet-derived interferon gamma (IFN-γ) leads to malignant transformation and impaired milk quality in healthy lactating bovine mammary epithelial cells (BMECs). However, the molecular mechanism of IFN-γ-induced arginine depletion is unclear. In this study, the BMEC cell line, mammary alveolar cells-large T antigen cells (MAC-T), was stimulated with IFN-γ (10 ng/mL) for 24 h, and cellular arginine and ornithine quantified by liquid chromatography-tandem mass spectrometry. Carnosine synthase 1 (CARNS1) was identified from RNA-seq data, CARNS1 knockdown was achieved using an shRNA interfering plasmid. The expression levels of CARNS1, argininosuccinate synthetase 1 (ASS1), mitogen-activated protein kinase 11 (p38 MAPK), and phosphorylated (p)-p38, and their cognate genes, were analyzed by Western blotting and real-time quantitative polymerase chain reaction. The results showed that IFN-γ inhibited the biosynthesis of arginine, but enhanced its catalysis via disruption of key enzymes involved in arginine metabolism. IFN-γ also inhibited the expression of CARNS1, ASS1, and cationic amino acid transporter 1, while activating the expression and phosphorylation of p38. However, knockdown of CARNS1 reduced arginine level and ASS1 expression and block of either the IFN-γ receptor IFN-γ receptor 2 or p38 relieved both the expression of Carnosine synthase 1 (CARNS1) and ASS1. In summary, these results indicate that IFN-γ induced arginine depletion through inhibition of CARNS1 signaling via activation of p38 in BMECs. These findings provide a novel insight for IFN-γ-related disease control strategies in dairy cows.

Structural characterization and expression analysis of novel MAPK1 transcript variants with the development of a multiplexed targeted nanopore sequencing approach

Mitogen-activated protein kinases (MAPKs) represent a protein family firmly involved in many signaling cascades, regulating a vast spectrum of stimulated cellular processes. Studies have shown that alternatively spliced isoforms of MAPKs play a crucial role in determining the desired cell fate in response to specific stimulations. Although the implication of most MAPKs transcript variants in the MAPK signaling cascades has been clarified, the transcriptional profile of a pivotal member, MAPK1, has not been investigated for the existence of additional isoforms. In the current study we developed and implemented targeted long-read and short-read sequencing approaches to identify novel MAPK1 splice variants. The combination of nanopore sequencing and NGS enabled the implementation of a long-read polishing pipeline using error-rate correction algorithms, which empowered the high accuracy of the results and increased the sequencing efficiency. The utilized multiplexing option in the nanopore sequencing approach allowed not only the identification of novel MAPK1 mRNAs, but also elucidated their expression profile in multiple human malignancies and non-cancerous cell lines. Our study highlights for the first time the existence of ten previously undescribed MAPK1 mRNAs (MAPK1 v.3 - v.12) and evaluates their relative expression levels in comparison to the main MAPK1 v.1. The optimization and employment of qPCR assays revealed that MAPK1 v.3 - v.12 can be quantified in a wide spectrum of human cell lines with notable specificity. Finally, our findings suggest that the novel protein-coding mRNAs are highly expected to participate in the regulation of MAPK pathways, demonstrating differential localizations and functionalities.

Novel p38 Mitogen-Activated Protein Kinase Inhibitor Reverses Hypoxia-Induced Pulmonary Arterial Hypertension in Rats

Mitogen-activated protein kinase (MAPK) signaling is strongly implicated in cardiovascular remodeling in pulmonary hypertension (PH) and right ventricle (RV) failure. The effects of a newly designed p38 inhibitor, LASSBio-1824, were investigated in experimentally induced PH. Male Wistar rats were exposed to hypoxia and SU5416 (SuHx), and normoxic rats were used as controls. Oral treatment was performed for 14 days with either vehicle or LASSBio-1824 (50 mg/kg). Pulmonary vascular resistance and RV structure and function were assessed by echocardiography and catheterization. Histological, immunohistochemical and Western blot analysis of lung and RV were performed to investigate cardiovascular remodeling and inflammation. Treatment with LASSBio-1824 normalized vascular resistance by attenuating vessel muscularization and endothelial dysfunction. In the heart, treatment decreased RV systolic pressure, hypertrophy and collagen content, improving cardiac function. Protein content of TNF-α, iNOS, phosphorylated p38 and caspase-3 were reduced both in lung vessels and RV tissues after treatment and a reduced activation of transcription factor c-fos was found in cardiomyocytes of treated SuHx rats. Therefore, LASSBio-1824 represents a potential candidate for remodeling-targeted treatment of PH.

Molecular signaling pathways, pathophysiological features in various organs, and treatment strategies in SARS-CoV2 infection

Cytokine storms and extra-activated cytokine signaling pathways can lead to severe tissue damage and patient death. Activation of inflammatory signaling pathways during Cytokine storms are an important factor in the development of acute respiratory syndrome (SARS-CoV-2), which is the major health problem today, causing systemic and local inflammation. Cytokine storms attract many inflammatory cells that attack the lungs and other organs and cause tissue damage. Angiotensin-converting enzyme 2 (ACE2) are expressed in a different type of tissues. inhibition of ACE2 activity impairs renin-angiotensin (RAS) function, which is related to the severity of symptoms and mortality rate in COVID-19 patients. Different signaling cascades are activated, affecting various organs during SARS-CoV-2 infection. Nowadays, there is no specific treatment for COVID-19, but scientists have recognized and proposed several treatment alternatives, including applying cytokine inhibitors, immunomodulators, and plasma therapy. Herein, we have provided the detailed mechanism of SARS-CoV-2 induced cytokine signaling and its connection with pathophysiological features in different organs. Possible treatment options to cope with the severe clinical manifestations of COVID-19 are also discussed.

A potent tumor-selective ERK pathway inactivator with high therapeutic index

FDA-approved BRAF and MEK small molecule inhibitors have demonstrated some level of efficacy in patients with metastatic melanomas. However, these "targeted" therapeutics have a very low therapeutic index, since these agents affect normal cells, causing undesirable, even fatal, side effects. To address these significant drawbacks, here, we have reengineered the anthrax toxin-based protein delivery system to develop a potent, tumor-selective MEK inactivator. This toxin-based MEK inactivator exhibits potent activity against a wide range of solid tumors, with the highest activity seen when directed toward tumors containing the BRAF^V600E mutation. We demonstrate that this reengineered MEK inactivator also exhibits an extremely high therapeutic index (>15), due to its in vitro and in vivo activity being strictly dependent on the expression of multiple tumor-associated factors including tumor-associated proteases matrix metalloproteinase, urokinase plasminogen activator, and anthrax toxin receptor capillary morphogenesis protein-2. Furthermore, we have improved the specificity of this MEK inactivator, restricting its enzymatic activity to only target the ERK pathway, thereby greatly diminishing off-target toxicity. Together, these data suggest that engineered bacterial toxins can be modified to have significant in vitro and in vivo therapeutic effects with high therapeutic index.

Endothelial shear stress signal transduction and atherogenesis: From mechanisms to therapeutics

Atherosclerotic vascular disease and its complications are among the top causes of mortality worldwide. In the vascular lumen, atherosclerotic plaques are not randomly distributed. Instead, they are preferentially localized at the curvature and bifurcations along the arterial tree, where shear stress is low or disturbed. Numerous studies demonstrate that endothelial cell phenotypic change (e.g., inflammation, oxidative stress, endoplasmic reticulum stress, apoptosis, autophagy, endothelial-mesenchymal transition, endothelial permeability, epigenetic regulation, and endothelial metabolic adaptation) induced by oscillatory shear force play a fundamental role in the initiation and progression of atherosclerosis. Mechano-sensors, adaptor proteins, kinases, and transcriptional factors work closely at different layers to transduce the shear stress force from the plasma membrane to the nucleus in endothelial cells, thereby controlling the expression of genes that determine cell fate and phenotype. An in-depth understanding of these mechano-sensitive signaling cascades shall provide new translational strategies for therapeutic intervention of atherosclerotic vascular disease. This review updates the recent advances in endothelial mechano-transduction and its role in the pathogenesis of atherosclerosis, and highlights the perspective of new anti-atherosclerosis therapies through targeting these mechano-regulated signaling molecules.

Protective Effects of High-Fat Diet against Murine Colitis in Association with Leptin Signaling and Gut Microbiome

Inflammatory bowel disease (IBD) is characterized by chronic intestinal-tract inflammation with dysregulated immune responses, which are partly attributable to dysbiosis. Given that diet plays a critical role in IBD pathogenesis and progression, we elucidated the effects of a high-fat diet (HFD) feeding on IBD development in relation to immune dysfunction and the gut microbiota. Five-week-old male C57BL/6J mice were fed either a normal diet (ND) or HFD for 14 weeks. The animals were further divided into ND, ND+ dextran sulfate sodium (DSS), HFD, and HFD+DSS treatment groups. The HFD+DSS mice exhibited lower body weight loss, lower disease activity index, longer colon length, and increased tight-junction protein expression and goblet-cell proportions compared with the ND+DSS mice. The T helper (h)1 and Th17 cell populations and pro-inflammatory cytokines involved in colitis pathogenesis were significantly more reduced in the HFD+DSS mice than in the ND+DSS mice. The HFD+DSS mice showed significantly increased serum leptin concentrations, colonic leptin receptor expression, enhanced anti-apoptotic AKT expression, and reduced pro-apoptotic MAPK and Bax expression compared with the ND+DSS mice, suggesting the involvement of the leptin-mediated pathway in intestinal epithelial cell apoptosis. The alterations in the gut-microbiota composition in the HFD+DSS group were the opposite of those in the ND+DSS group and rather similar to those of the ND group, indicating that the protective effects of HFD feeding against DSS-induced colitis are associated with changes in gut-microbiota composition. Overall, HFD feeding ameliorates DSS-induced colitis and colonic mucosal damage by reinforcing colonic barrier function and regulating immune responses in association with changes in gut-microbiota composition.

Identification and verification of the role of crucial genes through which methionine restriction inhibits the progression of colon cancer cells

Studies have shown that methionine restriction (MR) can inhibit tumor progression, but its mechanism in colon cancer is unknown. Through DESeq2 and Edge analysis of the GSE72131 and GSE103602 datasets, 649 co-upregulated and 532 co-downregulated genes affected by MR were identified, respectively. Enrichment analysis showed that these genes were closely associated with tumor progression. Combined with the differentially expressed genes of colon cancer in The Cancer Genome Atlas database, MR affected 330 dysregulated genes in colon cancer. On this basis, a transcriptional regulatory and competing endogenous RNA network was established and F transcription factor 1 and microRNA 17-92a-1 Cluster Host Gene were identified as a key transcription factor and long non-coding RNA, respectively. In addition, four genes (FA Complementation Group I, Holliday Junction Recognition Protein, Karyopherin Subunit Alpha 2 and Kinesin Family Member 15) were identified by analyzing the relationship between dysregulated genes and overall survival. Finally, western blotting, reverse transcription-quantitative PCR, Transwell and other in vitro experiments verified that MR inhibits HCT116 colon cancer cell proliferation, metastasis and invasion, induces apoptosis and downregulates 6 hub genes. Collectively, the present study identified potential targets for MR to inhibit colon cancer progression and contributed to the clinical application of MR.

PROTACs: great opportunities for academia and industry (an update from 2020 to 2021)

PROteolysis TArgeting Chimeras (PROTACs) technology is a new protein-degradation strategy that has emerged in recent years. It uses bifunctional small molecules to induce the ubiquitination and degradation of target proteins through the ubiquitin–proteasome system. PROTACs can not only be used as potential clinical treatments for diseases such as cancer, immune disorders, viral infections, and neurodegenerative diseases, but also provide unique chemical knockdown tools for biological research in a catalytic, reversible, and rapid manner. In 2019, our group published a review article “PROTACs: great opportunities for academia and industry” in the journal, summarizing the representative compounds of PROTACs reported before the end of 2019. In the past 2 years, the entire field of protein degradation has experienced rapid development, including not only a large increase in the number of research papers on protein-degradation technology but also a rapid increase in the number of small-molecule degraders that have entered the clinical and will enter the clinical stage. In addition to PROTAC and molecular glue technology, other new degradation technologies are also developing rapidly. In this article, we mainly summarize and review the representative PROTACs of related targets published in 2020–2021 to present to researchers the exciting developments in the field of protein degradation. The problems that need to be solved in this field will also be briefly introduced.

Neuroinflammation in Vascular Cognitive Impairment and Dementia: Current Evidence, Advances, and Prospects

Vascular cognitive impairment and dementia (VCID) is a major heterogeneous brain disease caused by multiple factors, and it is the second most common type of dementia in the world. It is caused by long-term chronic low perfusion in the whole brain or local brain area, and it eventually develops into severe cognitive dysfunction syndrome. Because of the disease’s ambiguous classification and diagnostic criteria, there is no clear treatment strategy for VCID, and the association between cerebrovascular pathology and cognitive impairment is controversial. Neuroinflammation is an immunological cascade reaction mediated by glial cells in the central nervous system where innate immunity resides. Inflammatory reactions could be triggered by various damaging events, including hypoxia, ischemia, and infection. Long-term chronic hypoperfusion-induced ischemia and hypoxia can overactivate neuroinflammation, causing apoptosis, blood–brain barrier damage and other pathological changes, triggering or aggravating the occurrence and development of VCID. In this review, we will explore the mechanisms of neuroinflammation induced by ischemia and hypoxia caused by chronic hypoperfusion and emphasize the important role of neuroinflammation in the development of VCID from the perspective of immune cells, immune mediators and immune signaling pathways, so as to provide valuable ideas for the prevention and treatment of the disease.

Beneficial effects of genistein in suppression of proliferation, inhibition of metastasis, and induction of apoptosis in PC3 prostate cancer cells

OBJECTIVES

Beneficial effects of genistein have been studied in various cancer types but the underlying molecular mechanisms of its actions have not been well established. This study investigated the effects of genistein on caspase-3 and p38 mitogen-activated protein kinase (p38MAPK) as main cellular signalling targets in PC3 prostate cancer cells.

METHODS

Caspase-3 and p38MAPK gene expression and intracellular protein levels were determined. Matrix metalloproteinase-2 (MMP2) gelatinase activity and caspase-3 enzyme activity were measured and PC3 cell migration and proliferation potencies were assessed.

RESULTS

Genistein induced apoptosis by enhancing the gene expression, intracellular protein level, and enzyme activity of caspase-3. Genistein also inhibited cell proliferation by reducing p38MAPK gene expression and protein level and strongly suppressed metastatic potency of PC3 cells by reducing MMP2 activity.

CONCLUSION

Genistein exhibits its beneficial anticancer properties on PC3 cells by reducing metastatic potency and regulating caspase-3 and p38MAPK pathways at different transcriptional and protein levels.

p38α Deficiency in T Cells Ameliorates Diet-Induced Obesity, Insulin Resistance, and Adipose Tissue Senescence

Adipose tissue-resident T cells play vital roles in regulating inflammation and metabolism in obesity, but the underlying mechanisms remain unclear. Here, we show that high-fat diet (HFD) feeding enhances p38 activity in adipose-resident T cells. T cell-specific deletion of p38α, an essential subunit of p38 expressed in most immune cells, protected mice from HFD-induced obesity, hepatic steatosis, adipose tissue inflammation, and insulin resistance. Mice with p38α deletion in T cells exhibited higher energy expenditure. Mechanistically, p38α promoted T-cell glycolysis through mechanistic target of rapamycin signaling, leading to enhanced Th1 differentiation. Accordingly, genetic deletion of p38α alleviated ongoing diet-induced obesity. Unexpectedly, p38α signaling in T cells promoted adipose tissue senescence during obesity and aging. Taken together, our results identify p38α in T cells as an essential regulator of obesity, insulin resistance, and adipose tissue senescence, and p38α may be a therapeutic target for obese- or aging-associated diseases.

Acute Ethanol Challenge Differentially Regulates Expression of Growth Factors and miRNA Expression Profile of Whole Tissue of the Dorsal Hippocampus

Acute ethanol exposure produces rapid alterations in neuroimmune gene expression that are both time- and cytokine-dependent. Interestingly, adolescent rats, who often consume binge-like quantities of alcohol, displayed reduced neuroimmune responses to acute ethanol challenge. However, it is not known whether growth factors, a related group of signaling factors, respond to ethanol similarly in adults and adolescents. Therefore, Experiment 1 aimed to assess the growth factor response to ethanol in both adolescents and adults. To test this, adolescent (P29-P34) and adult (P70-P80) Sprague Dawley rats of both sexes were injected with either ethanol (3.5 g/kg) or saline, and brains were harvested 3 h post-injection for assessment of growth factor, cytokine, or miRNA expression. As expected, acute ethanol challenge significantly increased IL-6 and IκBα expression in the hippocampus and amygdala, replicating our prior findings. Acute ethanol significantly decreased BDNF and increased FGF2 regardless of age condition. PDGF was unresponsive to ethanol, but showed heightened expression among adolescent males. Because recent work has focused on the PDE4 inhibitor ibudilast for treatment in alcohol use disorder, Experiment 2 tested whether ibudilast would alter ethanol-evoked gene expression changes in cytokines and growth factors in the CNS. Ibudilast (9.0 mg/kg s.c.) administration 1 h prior to ethanol had no effect on ethanol-induced changes in cytokine or growth factor changes in the hippocampus or amygdala. To further explore molecular alterations evoked by acute ethanol challenge in the adult rat hippocampus, Experiment 3 tested whether acute ethanol would change the miRNA expression profile of the dorsal hippocampus using RNASeq, which revealed a rapid suppression of 12 miRNA species 3 h after acute ethanol challenge. Of the miRNA affected by ethanol, the majority were related to inflammation or cell survival and proliferation factors, including FGF2, MAPK, NFκB, and VEGF. Overall, these findings suggest that ethanol-induced, rapid alterations in neuroimmune gene expression were (i) muted among adolescents; (ii) independent of PDE4 signaling; and (iii) accompanied by changes in several growth factors (increased FGF2, decreased BDNF). In addition, ethanol decreased expression of multiple miRNA species, suggesting a dynamic molecular profile of changes in the hippocampus within a few short hours after acute ethanol challenge. Together, these findings may provide important insight into the molecular consequences of heavy drinking in humans.

HSV-1 Infection of Epithelial Dendritic Cells Is a Critical Strategy for Interfering with Antiviral Immunity

Herpes simplex virus type 1 (HSV-1), an α subgroup member of the human herpesvirus family, infects cells via the binding of its various envelope glycoproteins to cellular membrane receptors, one of which is herpes virus entry mediator (HVEM), expressed on dendritic cells. Here, HVEM gene-deficient mice were used to investigate the immunologic effect elicited by the HSV-1 infection of dendritic cells. Dendritic cells expressing the surface marker CD11c showed an abnormal biological phenotype, including the altered transcription of various immune signaling molecules and inflammatory factors associated with innate immunity after viral replication. Furthermore, the viral infection of dendritic cells interfered with dendritic cell function in the lymph nodes, where these cells normally play roles in activating the T-cell response. Additionally, the mild clinicopathological manifestations observed during the acute phase of HSV-1 infection were associated with viral replication in dendritic cells.

Mosloflavone-Resveratrol Hybrid TMS-HDMF-5z Exhibits Potent In Vitro and In Vivo Anti-Inflammatory Effects Through NF-κB, AP-1, and JAK/STAT Inactivation

TMS-HDMF-5z is a hybrid of the natural products mosloflavone and resveratrol. It was discovered to show potent inhibitory effects against lipopolysaccharide (LPS)-induced production of inflammatory mediators in RAW 264.7 macrophages. However, its mechanism of action is unknown. Hence this study aimed to demonstrate and explore in vitro and in vivo anti-inflammatory effects of TMS-HDMF-5z and its mechanism of action employing RAW 264.7 macrophages and carrageenan-induced hind paw edema. This work revealed that TMS-HDMF-5z suppressed the LPS-induced inducible nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein, mRNA, and promoter binding levels and tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6, and interferon-β (IFN-β) at the mRNA expression in RAW 264.7 macrophages. The results showed that TMS-HDMF-5z reduced the transcription and DNA binding activities of nuclear factor-κB (NF-κB) through inhibiting nuclear translocation of p65 and phosphorylation of κB inhibitor α (IκBα), IκB kinase (IKK), and TGF-β activated kinase 1 (TAK1). Additionally, TMS-HDMF-5z attenuated the LPS-induced transcriptional and DNA binding activities of activator protein-1 (AP-1) by suppressing nuclear translocation of phosphorylated c-Fos, c-Jun, and activating transcription factor 2 (ATF2). TMS-HDMF-5z also reduced the LPS-induced phosphorylation of Janus kinase 1/2 (JAK1/2), signal transducers and activators of transcription 1/3 (STAT1/3), p38 mitogen-activated protein kinase (MAPK), and MAPK-activated protein kinase 2 (MK2). In rats, TMS-HDMF-5z alleviated carrageenan-induced hind paw edema through the suppressing iNOS and COX-2 via NF-κB, AP-1, and STAT1/3 inactivation. Collectively, the TMS-HDMF-5z-mediated inhibition of NF-κB, AP-1, and STAT1/3 offer an opportunity for the development of a potential treatment for inflammatory diseases.

Inhibition of PKC-δ reduce rhabdomyolysis-induced acute kidney injury

Despite extensive research, the mechanisms underlying rhabdomyolysis-induced acute kidney injury (AKI) remain largely elusive. In this study, we established both cell and murine models of rhabdomyolysis-induced AKI by using myoglobin and glycerin, respectively, and provided evidence that protein kinase Cδ (PKC-δ) was activated in both models and subsequently promoted cell apoptosis. Moreover, we found that this detrimental effect of PKC-δ activation can be reversed by its pharmaceutical inhibitor rottlerin. Furthermore, we detected and confirmed the existence of PKC-δ-mediated myoglobin-induced cell apoptosis and the expression of TNF-α and IL1-β via regulation of the p38MAPK and ERK1/2 signalling pathways. In summary, our research revealed the role of PKC-δ in renal cell apoptosis and suggests that PKC-δ is a viable therapeutic target for rhabdomyolysis-induced AKI.

Identification and characterization of MKK6 and AP-1 in Anodonta woodiana reveal their potential roles in the host defense response against bacterial challenge

Mitogen-activated protein kinase kinase 6 (MKK6) and activator protein-1 (AP-1) are two of the essential regulatory proteins in the p38 mitogen-activated protein kinase (MAPK) pathway, which participates in the innate immune response to bacterial infections. In this study, molluscan MKK6 (AwMKK6) and AP-1 (AwAP-1) genes were cloned and identified from Anodonta woodiana. The open reading frame (ORF) of AwMKK6 encodes for a putative polypeptide sequence of 345 amino acids containing a conserved serine/threonine protein kinase (S_TKc) domain, a SVAKT motif and a DVD domain. AwAP-1 consists of 294 amino acids including a typical nuclear localization signal (NLS), a Jun domain and a basic region leucine zipper (BRLZ) domain. Quantitative real-time PCR analysis showed that both AwMKK6 and AwAP-1 were widely expressed in all selected tissues of A. woodiana and their transcript levels in hemocytes were significantly upregulated when challenged with Aeromonas hydrophila and lipopolysaccharide (LPS). Additionally, the signaling molecules of the AwMKK6/AwAP-1 pathway including AwTLR4, AwMyD88, AwTRAF6, AwMEKK1, AwMEKK4, AwASK1, AwTAK1 and Awp38 mRNA expression showed a stronger responsiveness to LPS challenge in hemocytes of A. woodiana. RNA interference (RNAi) experiments indicated that the silencing of AwMKK6 or AwAP-1 could decrease the mRNA expression levels of immune effectors (AwTNF, AwLYZ and AwDefense). Subcellular localization studies suggested that AwMKK6 and AwAP-1 were distributed throughout the cells and nucleus, respectively, and their overexpression could significantly enhance the transcriptional activities of AP-1-Luc in HEK293T cells. These findings suggest that MKK6 and AP-1 play a major role in the host defense response to bacterial injection, which may make contributions to a better understanding of the immune function of the p38 MAPK pathway in mollusks.

Advances in indole-containing alkaloids as potential anticancer agents by regulating autophagy

Cancer is a leading cause of death worldwide, and cancer development is often associated with disturbances in the autophagy process. Autophagy is a catabolic process involved in many physiological processes, crucial for cell growth and survival. It is an intracellular lysosomal/vacuolar degradation system. In this system, inner cytoplasmic cell membrane is degraded by lysosomal hydrolases, and the products are released back into the cytoplasm. Indole alkaloids are natural products extensively found in nature and have been proven to possess various pharmacological activities. In recent years, pharmacological studies have demonstrated another potential of indole alkaloids, autophagy regulation. The regulation may contribute to the efficacy of indole alkaloids in preventing and treating cancer. This review summarizes the current understanding of indole alkaloids' effect on tumor cells and autophagy. Then, we focus on mechanisms by which indole alkaloids can target the autophagy process associated with cancer, including the PI3K/Akt/mTOR signaling pathway, MAPK signaling pathway, ROS signaling pathway, Beclin-1, and so on. Literature has been surveyed primarily from 2009 to Nov. 2021, and some semisynthetic or fully synthetic indole derivatives are also discussed.

miR-1908 Dysregulation in Human Cancers

MiR-1908 is a miRNA located in the intron of the fatty acid desaturase 1 (FADS1) gene. The expression level of miR-1908 is abnormal in many diseases such as cancer. miR-1908 can inhibit the expression of at least 27 target genes by binding to the 3’ untranslated region (3’ UTR) of target genes. miR-1908 is involved in the biological processes of cell proliferation, cell differentiation, cell apoptosis, cancer cell invasion, and metastasis. The expression of miR-1908 is regulated by 11 factors, including lncRNA HOTTIP, adipokines (TNF-α, leptin, and resistin), NF-κB, free fatty acid (FFA), cholesterol, stearoyl-CoA desaturase (SCD1), immune-related transcription factors (STAT1, RB1, and IRF1). The expression of miR-1908 is also affected by the anticancer drug OSW-1, growth hormone (GH), and the anticonvulsant drug sodium valproate. In addition, the aberrant expression of miR-1908 is also related to the prognosis of a variety of cancers, including non-small cell lung cancer (NSCLC), ovarian cancer (OC), breast cancer, cervical cancer, glioma, high-grade serous ovarian carcinoma (HGSOC), osteosarcoma, etc. This article summarizes the abnormal expression pattern of miR-1908 in various diseases and its molecular regulation mechanisms. Our work will provide potential hints and direction for future miR-1908-related research.

Inhibition of p38 MAPK decreases hyperglycemia-induced nephrin endocytosis and attenuates albuminuria

Abstract

Chronic hyperglycemia, as in diabetes mellitus, may cause glomerular damage with microalbuminuria as an early sign. Noteworthy, even acute hyperglycemia can increase glomerular permeability before structural damage of the glomerular filter can be detected. Despite intensive research, specific antiproteinuric therapy is not available so far. Thus, a deeper understanding of the molecular mechanisms of albuminuria is desirable. P38 MAPK signaling is involved in the development of hyperglycemia-induced albuminuria. However, the mechanism of increased p38 MAPK activity leading to increased permeability and albuminuria remained unclear. Recently, we demonstrated that acute hyperglycemia triggers endocytosis of nephrin, the key molecule of the slit diaphragm, and induces albuminuria. Here, we identify p38 MAPK as a pivotal regulator of hyperglycemia-induced nephrin endocytosis. Activated p38 MAPK phosphorylates the nephrin c-terminus at serine 1146, facilitating the interaction of PKCα with nephrin. PKCα phosphorylates nephrin at threonine residues 1120 and 1125, mediating the binding of β-arrestin2 to nephrin. β-arrestin2 triggers endocytosis of nephrin by coupling it to the endocytic machinery, leading to increased glomerular permeability. Pharmacological inhibition of p38 MAPK preserves nephrin surface expression and significantly attenuates albuminuria.

Key messages

Acute hyperglycemia triggers endocytosis of nephrin.

Activated p38 MAPK phosphorylates the nephrin c-terminus at serine 1146, facilitating the interaction of PKCα with nephrin.

PKCα phosphorylates nephrin at threonine residues 1120 and 1125, mediating the binding of β-arrestin2 to nephrin.

β-arrestin2 triggers endocytosis of nephrin by coupling it to the endocytic machinery, leading to a leaky glomerular filter.

Pharmacological inhibition of p38 MAPK preserves nephrin surface expression and significantly attenuates albuminuria under hyperglycemic conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00109-022-02184-5.

Unresolved stalled ribosome complexes restrict cell-cycle progression after genotoxic stress

During the translation surveillance mechanism known as ribosome-associated quality control, the ASC-1 complex (ASCC) disassembles ribosomes stalled on the mRNA. Here, we show that there are two distinct classes of stalled ribosome. Ribosomes stalled by translation elongation inhibitors or methylated mRNA are short lived in human cells because they are split by the ASCC. In contrast, although ultraviolet light and 4-nitroquinoline 1-oxide induce ribosome stalling by damaging mRNA, and the ASCC is recruited to these stalled ribosomes, we found that they are refractory to the ASCC. Consequently, unresolved UV- and 4NQO-stalled ribosomes persist in human cells. We show that ribosome stalling activates cell-cycle arrest, partly through ZAK-p38MAPK signaling, and that this cell-cycle delay is prolonged when the ASCC cannot resolve stalled ribosomes. Thus, we propose that the sensitivity of stalled ribosomes to the ASCC influences the kinetics of stall resolution, which in turn controls the adaptive stress response.

Regulatory effects of a novel cysteine protease inhibitor in Baylisascaris schroederi migratory larvae on mice immune cells

Background

The giant panda (Ailuropoda melanoleuca) is a well-known, rare and endangered species. Baylisascaris schroederi is a pathogenic ascarid. Infection with B. schroederi may cause death in giant pandas. At present, the immune evasion mechanism of B. schroederi is little known. Cysteine protease inhibitors (CPI) play important roles in the regulation of host immune responses against certain nematodes. In this study, we focused on the analysis of the regulation of B. schroederi migratory larvae CPI (rBsCPI-1) on mice immune cells.

Methods

First, the pattern recognition receptors on the surface of peripheral blood mononuclear cells (PBMCs) and the signal pathways that transduce extracellular signals into the nucleus activated by rBsCPI-1 were identified. Then, the regulatory effects of rBsCPI-1 on PBMCs physiological activities were detected. Finally, the effects of rBsCPI-1 on TLR signaling pathway activation and NF-κB phosphorylation in mice immunized with recombinant protein were analysed.

Results

The results suggested that rBsCPI-1 secreted by B. schroederi migratory larvae is mainly recognized by TLR2 and TLR4 on PBMCs. Extracellular signals are transduced into the nucleus through the MAPK and NF-κB signaling pathways, enhancing the phagocytosis, migration, and apoptosis of PBMCs; meanwhile, rBsCPI-1 induces high expression of NO. Thus, rBsCPI-1 plays a role in immune regulation. In addition, the high expression of negative regulatory factors also ensured that TLR activation is maintained at the optimal level.

Conclusions

rBsCPI-1 can transduce regulatory signals into immune cells by activating the TLR2/4-NF-κB/MAPK signaling pathway, having a certain regulatory effect on the physiological activities. Meanwhile, rBsCPI-1 can maintain the immune response in a balance by limiting the over-activation of the TLRs signaling pathway and thus contributes to B. schroederi immune evasion.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05240-8.

Glutamine deficiency shifts the asthmatic state toward neutrophilic airway inflammation

Background

The administration of L‐glutamine (Gln) suppresses allergic airway inflammation via the rapid upregulation of MAPK phosphatase (MKP)‐1, which functions as a negative regulator of inflammation by deactivating p38 and JNK mitogen‐activated protein kinases (MAPKs). However, the role of endogenous Gln remains to be elucidated. Therefore, we investigated the mechanism by which endogenous Gln regulates MKP‐1 induction and allergic airway inflammation in an ovalbumin‐based murine asthma model.

Methods

We depleted endogenous Gln levels using L‐γ‐glutamyl‐p‐nitroanilide (GPNA), an inhibitor of the Gln transporter ASCT2 and glutamine synthetase small interfering siRNA. Lentivirus expressing MKP‐1 was injected to achieve overexpression of MKP‐1. Asthmatic phenotypes were assessed using our previously developed ovalbumin‐based murine model, which is suitable for examining sequential asthmatic events, including neutrophil infiltration. Gln levels were analyzed using a Gln assay kit.

Results

GPNA or glutamine synthetase siRNA successfully depleted endogenous Gln levels. Importantly, homeostatic MKP‐1 induction did not occur at all, which resulted in prolonged p38 MAPK and cytosolic phospholipase A₂ (cPLA₂) phosphorylation in Gln‐deficient mice. Gln deficiency augmented all examined asthmatic reactions, but it exhibited a strong bias toward increasing the neutrophil count, which was not observed in MKP‐1‐overexpressing lungs. This neutrophilia was inhibited by a cPLA₂ inhibitor and a leukotriene B4 inhibitor but not by dexamethasone.

Conclusion

Gln deficiency leads to the impairment of MKP‐1 induction and activation of p38 MAPK and cPLA₂, resulting in the augmentation of neutrophilic, more so than eosinophilic, airway inflammation.

Yiqi Tongluo Fang could preventive and delayed development and formation of diabetic retinopathy through antioxidant and anti-inflammatory effects

BACKGROUND

Yiqi Tongluo Fang (YQTLF) is an effective prescription for the treatment of diabetic retinopathy (DR), but its mechanism of action remains unclear.

METHOD

The content of YQTLF was determined using liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS, respectively). Twenty-five Sprague Dawley (SD) rats were randomly selected as the normal control group. One hundred SD streptozotocin-induced diabetes (type 1) rats were randomly divided into diabetic control, diabetic+insulin+ calcium dobesilate (CaD), and diabetic+insulin+ YQTLF groups, with 25 rats in each group. Bodyweight level was measured every 2 weeks. After 12 weeks of gavage, the glucose levels, lipids, oxidative stress, inflammation, retinal histopathology, and the blood-retinal barrier were assessed in each group. The p38 MAPK pathway was changed to explore its internal mechanism. The measurement data were expressed as mean ± standard deviation, and different statistical methods were used according to a normal distribution, square error, or not.

RESULTS

A total of 1024 valid peaks were identified in YQTLF using GC-MS. YQTLF significantly lowered the fasting blood glucose levels in diabetic rats. YQTLF early inhibited changes in retinal histology, capillaries, cells, and tight junction proteins (such as ZO-1, occludin, claudin-5, and VE-cadherin) before the formation and development of DR. These findings correlated with the alleviation of glucolipid metabolism, inflammation, and oxidative stress. The lncRNA MALAT1 and the PRC 2/p38 MAPK-related pathway, such as the expression of EZH2, SUZ12, EED, p38 MAPK, MMP-9, and VEGFR, were also correlated.

CONCLUSION

We have demonstrated the molecular and cellular mechanisms underlying the preventive and delayed development and formation of DR. YQTLF prevents changes in dyslipidemia, retinal histology, capillaries, cells, and tight junction proteins. These protective effects appear to be linked to its antioxidant and anti-inflammatory effects, which prevent the activation of intracellular signaling pathways, such as the lncRNA MALAT1 and PRC 2/p38 MAPK-related pathway.

Metastasis and MAPK Pathways

Cancer is a leading cause of death worldwide. In many cases, the treatment of the disease is limited due to the metastasis of cells to distant locations of the body through the blood and lymphatic drainage. Most of the anticancer therapeutic options focus mainly on the inhibition of tumor cell growth or the induction of cell death, and do not consider the molecular basis of metastasis. The aim of this work is to provide a comprehensive review focusing on cancer metastasis and the mitogen-activated protein kinase (MAPK) pathway (ERK/JNK/P38 signaling) as a crucial modulator of this process.