Identification of atypical mitogen-activated protein kinase MAPK4 as a novel regulator in acute lung injury

A review of non-classical MAPK family member, MAPK4: A pivotal player in cancer development and therapeutic intervention

Mitogen-Activated Protein Kinases (MAPKs) are serine/threonine protein kinases that play a crucial role in transmitting extracellular signals to the intracellular environment, influencing a wide range of cellular processes including proliferation, differentiation, apoptosis, metabolic activities, immune function and stress response. MAPK4, a non-classical MAPK, is frequently overexpressed in various malignancies, including prostate, breast, cervix, thyroid, and gliomas. It orchestrates cell proliferation, migration, and apoptosis via the AKT/mTOR and/or PDK1 signaling pathways, thus facilitating tumor cell growth. Furthermore, MAPK4 expression is closely associated with the effectiveness of specific inhibitors like PI3K and PARP1, and also correlate with the survival rates of cancer patients. Increasing evidence highlights MAPK4's involvement in the tumor microenvironment, modulating immune response and inflammation-related diseases. This review comprehensively explores the structure, function, and oncogenic role of MAPK4, providing a deeper understanding of its activation and mechanisms of action in tumorigenesis, which might be helpful for the development of innovative therapeutic strategies for cancer management.

MAPK4 facilitates angiogenesis by inhibiting the ERK pathway in non-small cell lung cancer

Background

Angiogenesis plays an important role in the occurrence and development of non-small cell lung cancer (NSCLC). The atypical mitogen-activated protein kinase 4 (MAPK4) has been shown to be involved in the pathogenesis of various diseases. However, the potential role of MAPK4 in the tumor angiogenesis of NSCLC remains unclear.

Methods

Adult male C57BL/6 wild-type mice were randomly divided into the control group and p-siMAPK4 intervention group, respectively. The cell proliferation was analyzed with flow cytometry and immunofluorescence staining. The vascular density in tumor mass was analyzed by immunofluorescence staining. The expressions of MAPK4 and related signaling molecules were detected by western blot analysis and immunofluorescence staining, and so on.

Results

We found that the expression of MAPK4, which was dominantly expressed in local endothelial cells (ECs), was correlated with tumor angiogenesis of NSCLC. Furthermore, MAPK4 silencing inhibited the proliferation and migration abilities of human umbilical vein ECs (HUVECs). Global gene analysis showed that MAPK4 silencing altered the expression of multiple genes related to cell cycle and angiogenesis pathways, and that MAPK4 silencing increased transduction of the extracellular regulated protein kinases 1/2 (ERK1/2) pathway but not Akt and c-Jun n-terminal kinase pathways. Further analysis showed that MAPK4 silencing inhibited the proliferation and migration abilities of HUVECs cultured in tumor cell supernatant, which was accompanied with increased transduction of the ERK1/2 pathway. Clinical data analysis suggested that the higher expression of MAPK4 and CD34 were associated with poor prognosis of patients with NSCLC. Targeted silencing of MAPK4 in ECs using small interfering RNA driven by the CD34 promoter effectively inhibited tumor angiogenesis and growth of NSCLC in vivo.

Conclusion

Our results reveal that MAPK4 plays an important role in the angiogenesis and development of NSCLC. MAPK4 may thus represent a new target for NSCLC.

Potential role of LPAR5 gene in prognosis and immunity of thyroid papillary carcinoma and pan-cancer

Papillary carcinomas account for the largest proportion of thyroid cancers, with papillary thyroid carcinoma (PTC) being prone to early lymph node metastasis. Some studies have confirmed that LPAR5 can promote the progression of PTC, but immune-related analyses of LPAR5 and PTC have not been widely discussed. This study aimed to determine the role of LPAR5 in PTC prognosis and immunity. We will further explore the role of LPAR5 in 33 different tumor types. Regarding PTC, we analyzed the effect of LPAR5 expression on overall survival (OS). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. Immune-related analyses of immune checkpoints (ICPs) and immune cell infiltration were also performed. For pan-cancer, R packages were used to analyze prognosis, tumor mutational burden (TMB), microsatellite instability (MSI), and immune cell infiltration. Analysis of tumor microenvironment (TME) and ICPs was performed using Sangerbox ( http://vip.sangerbox.com/home.html ). The TISIDB database ( http://cis.hku.hk/TISIDB/index.php ) was used to identify immune and molecular subtypes. LPAR5 expression is associated with PTC prognosis and immunity as well as various human tumors. LPAR5 may be a potential biomarker for multiple malignancies and may provide a new target for cancer immunotherapy.

MicroRNA-9-5p Is Involved in Lipopolysaccharide-Induced Acute Lung Injury Via the Regulation of Macrophage Polarization

MicroRNA (miR)-9-5 p has been shown to affect lung cancer progression and lung fibrosis, but the efficacy of miR-9-5 p in acute lung injury (ALI) remained indefinite. The study was performed to probe the modulating mechanism of miR-9-5 p in ALI via regulating macrophage polarization. The ALI mouse model was established and blood samples of ALI patients were obtained. MiR-9-5 p levels in ALI mice and ALI patients were detected. Mouse pulmonary macrophages were extracted from bronchoalveolar lavage fluid and polarized into M1 and M2 macrophages. Intervention of miR-9-5 p expression was performed to observe the effects on M1 polarization and M2 polarization in lung macrophages, inflammatory factors in BALF, wet/dry weight ratio (W/D) in lung tissues, myeloperoxidase (MPO) activity in lung tissues, and lung tissue lesion condition. MiR-9-5 p levels were elevated in the lung tissues of ALI mice and ALI patients. MiR-9-5 p silencing could repress lung macrophages in ALI mice polarized toward the M1 phenotype and promoted the polarization toward the M2 phenotype, reduced the lung lesions, the lung water content, and the secretion levels of the pro-inflammatory factors TNF-α, IL-6, and IL-1β in BALF, increased the secretion of the anti-inflammatory factor IL-10, as well as impeded the MPO activity in the lung tissues of ALI mice. MiR-9-5 p deletion ameliorates LPS-induced inflammatory infiltration in lung tissues via inhibiting the polarization of mouse lung macrophages to the M1 phenotype and promoting the polarization to the M2 phenotype.

Epigenetics and stroke: role of DNA methylation and effect of aging on blood-brain barrier recovery

Incomplete recovery of blood-brain barrier (BBB) function contributes to stroke outcomes. How the BBB recovers after stroke remains largely unknown. Emerging evidence suggests that epigenetic factors play a significant role in regulating post-stroke BBB recovery. This study aimed to evaluate the epigenetic and transcriptional profile of cerebral microvessels after thromboembolic (TE) stroke to define potential causes of limited BBB recovery. RNA-sequencing and reduced representation bisulfite sequencing (RRBS) analyses were performed using microvessels isolated from young (6 months) and old (18 months) mice seven days poststroke compared to age-matched sham controls. DNA methylation profiling of poststroke brain microvessels revealed 11,287 differentially methylated regions (DMR) in old and 9818 DMR in young mice, corresponding to annotated genes. These DMR were enriched in genes encoding cell structural proteins (e.g., cell junction, and cell polarity, actin cytoskeleton, extracellular matrix), transporters and channels (e.g., potassium transmembrane transporter, organic anion and inorganic cation transporters, calcium ion transport), and proteins involved in endothelial cell processes (e.g., angiogenesis/vasculogenesis, cell signaling and transcription regulation). Integrated analysis of methylation and RNA sequencing identified changes in cell junctions (occludin), actin remodeling (ezrin) as well as signaling pathways like Rho GTPase (RhoA and Cdc42ep4). Aging as a hub of aberrant methylation affected BBB recovery processes by profound alterations (hypermethylation and repression) in structural protein expression (e.g., claudin-5) as well as activation of a set of genes involved in endothelial to mesenchymal transformation (e.g., Sox9, Snai1), repression of angiogenesis and epigenetic regulation. These findings revealed that DNA methylation plays an important role in regulating BBB repair after stroke, through regulating processes associated with BBB restoration and prevalently with processes enhancing BBB injury.

The Atypical MAP Kinase MAPK15 Is Required for Lung Adenocarcinoma Metastasis via Its Interaction with NF-κB p50 Subunit and Transcriptional Regulation of Prostaglandin E2 Receptor EP3 Subtype

Studying the relatively underexplored atypical MAP Kinase MAPK15 on cancer progression/patient outcomes and its potential transcriptional regulation of downstream genes would be highly valuable for the diagnosis, prognosis, and potential oncotherapy of malignant tumors such as lung adenocarcinoma (LUAD). Here, the expression of MAPK15 in LUAD was detected by immunohistochemistry and its correlation with clinical parameters such as lymph node metastasis and clinical stage was analyzed. The correlation between the prostaglandin E2 receptor EP3 subtype (EP3) and MAPK15 expression in LUAD tissues was examined, and the transcriptional regulation of EP3 and cell migration by MAPK15 in LUAD cell lines were studied using the luciferase reporter assay, immunoblot analysis, qRT-PCR, and transwell assay. We found that MAPK15 is highly expressed in LUAD with lymph node metastasis. In addition, EP3 is positively correlated with the expression of MAPK15 in LUAD tissues, and we confirmed that MAPK15 transcriptionally regulates the expression of EP3. Upon the knockdown of MAPK15, the expression of EP3 was down-regulated and the cell migration ability was decreased in vitro; similarly, the mesenteric metastasis ability of the MAPK15 knockdown cells was inhibited in in vivo animal experiments. Mechanistically, we demonstrate for the first time that MAPK15 interacts with NF-κB p50 and enters the nucleus, and NF-κB p50 binds to the EP3 promoter and transcriptionally regulates the expression of EP3. Taken together, we show that a novel atypical MAPK and NF-κB subunit interaction promotes LUAD cell migration through transcriptional regulation of EP3, and higher MAPK15 level is associated with lymph node metastasis in patients with LUAD.

Epigenetics and stroke: role of DNA methylation and effect of aging on blood-brain barrier recovery

Incomplete recovery of blood-brain barrier (BBB) function contributes to stroke outcomes. How the BBB recovers after stroke remains largely unknown. Emerging evidence suggests that epigenetic factors play a significant role in regulating post-stroke BBB recovery. This study aimed to evaluate the epigenetic and transcriptional profile of cerebral microvessels after thromboembolic (TE) stroke to define potential causes of limited BBB recovery. RNA-sequencing and reduced representation bisulfite sequencing (RRBS) analyses were performed using microvessels isolated from young (6 months) and old (18 months) mice seven days poststroke compared to age-matched sham controls. DNA methylation profiling of poststroke brain microvessels revealed 11287 differentially methylated regions (DMR) in old and 9818 DMR in young mice, corresponding to annotated genes. These DMR were enriched in genes encoding cell structural proteins (e.g., cell junction, and cell polarity, actin cytoskeleton, extracellular matrix), transporters and channels (e.g., potassium transmembrane transporter, organic anion and inorganic cation transporters, calcium ion transport), and proteins involved in endothelial cell processes (e.g., angiogenesis/vasculogenesis, cell signaling and transcription regulation). Integrated analysis of methylation and RNA sequencing identified changes in cell junctions (occludin), actin remodeling (ezrin) as well as signaling pathways like Rho GTPase (RhoA and Cdc42ep4). Aging as a hub of aberrant methylation affected BBB recovery processes by profound alterations (hypermethylation and repression) in structural protein expression (e.g., claudin-5) as well as activation of a set of genes involved in endothelial to mesenchymal transformation (e.g., Sox17 , Snail1 ), repression of angiogenesis and epigenetic regulation. These findings revealed that DNA methylation plays an important role in regulating BBB repair after stroke, through regulating processes associated with BBB restoration and prevalently with processes enhancing BBB injury.

Epigenome-wide association study and epigenetic age acceleration associated with cigarette smoking among Costa Rican adults

Smoking-associated DNA methylation (DNAm) signatures are reproducible among studies of mostly European descent, with mixed evidence if smoking accelerates epigenetic aging and its relationship to longevity. We evaluated smoking-associated DNAm signatures in the Costa Rican Study on Longevity and Healthy Aging (CRELES), including participants from the high longevity region of Nicoya. We measured genome-wide DNAm in leukocytes, tested Epigenetic Age Acceleration (EAA) from five clocks and estimates of telomere length (DNAmTL), and examined effect modification by the high longevity region. 489 participants had a mean (SD) age of 79.4 (10.8) years, and 18% were from Nicoya. Overall, 7.6% reported currently smoking, 35% were former smokers, and 57.4% never smoked. 46 CpGs and five regions (e.g. AHRR, SCARNA6/SNORD39, SNORA20, and F2RL3) were differentially methylated for current smokers. Former smokers had increased Horvath’s EAA (1.69-years; 95% CI 0.72, 2.67), Hannum’s EAA (0.77-years; 95% CI 0.01, 1.52), GrimAge (2.34-years; 95% CI1.66, 3.02), extrinsic EAA (1.27-years; 95% CI 0.34, 2.21), intrinsic EAA (1.03-years; 95% CI 0.12, 1.94) and shorter DNAmTL (− 0.04-kb; 95% CI − 0.08, − 0.01) relative to non-smokers. There was no evidence of effect modification among residents of Nicoya. Our findings recapitulate previously reported and novel smoking-associated DNAm changes in a Latino cohort.