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Identification of CD55 as a downstream factor of EP4 receptor signaling in colorectal cancer cells.

Prostaglandin E2 (PGE2) signaling through the E-type prostanoid 4 (EP4) receptor has been implicated in the pathophysiology of colorectal cancer (CRC). We herein identified decay-accelerating factor, also known as CD55, as a novel CRC-associated downstream factor of the EP4 receptor. The integration of transcriptomic profiling of PGE2-stimulated HCA-7 human colon cancer cells with analyses of cancer genomic databases predicted CD55 as a potential EP4 receptor-regulated target. Inhibitor-based experiments showed the induction of CD55 after a PGE2 stimulation required the EP4 receptor and Gi protein in HCA-7 cells, whereas protein kinase A signaling was dispensable. In combination with a toxicogenomic database analysis, p38 mitogen-activated protein kinase (MAPK) was identified as the predominant effector connecting the EP4 receptor to CD55 upregulation. A single-cell RNA-seq re-analysis of human CRC tissues revealed CD55 upregulation and p38 MAPK-related gene set enrichment in epithelial cells expressing the EP4 receptor, suggesting that this induction mechanism may operate in a subset of epithelial cells in clinical specimens. Collectively, these results delineate a PGE2/EP4 receptor/Gi protein/p38 MAPK signaling axis that induces CD55 expression in HCA-7 cells and epithelial tumor cells, provide new mechanistic clues for understanding the regulation of complement regulatory molecule CD55 expression by prostaglandin signaling.

Humans

Context-dependent effects of MIR100HG on tumorigenic phenotypes and p38/MAPK-AKT signaling in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide and is characterized by a hypoxic tumor microenvironment that promotes tumor progression, cellular adaptation, and therapeutic resistance. Increasing evidence indicates that long non-coding RNAs (lncRNAs) play critical roles in regulating tumor-associated signaling networks; however, the contribution of MIR100HG to hepatocellular carcinoma progression, particularly under hypoxic conditions, remains insufficiently understood. In this study, we investigated the expression pattern and functional significance of MIR100HG in hepatocellular carcinoma using epithelial-like Hep3B and mesenchymal-like SNU-398 cells, together with non-tumor hepatocytes (Clone-9). Gain- and loss-of-function approaches were employed to evaluate the impact of MIR100HG on tumor-associated cellular phenotypes under both normoxic and hypoxic conditions. Functional assays demonstrated that MIR100HG overexpression significantly enhanced cell proliferation, clonogenic potential, migration, and invasion, whereas MIR100HG silencing markedly suppressed these tumorigenic properties and increased apoptotic cell death. Mechanistic analyses revealed that MIR100HG promotes oncogenic signaling through the p38/MAPK and AKT pathways under normoxic conditions, whereas MIR100HG depletion reduced the phosphorylation of these key signaling proteins. Notably, additional pathway analyses under hypoxia-mimicking conditions revealed a distinct signaling response, in which the MIR100HG-associated activation of p38/MAPK and AKT observed under normoxia was not maintained. Moreover, the expression patterns of AKT-associated regulatory genes, including GAS6 and PTEN, were reversed under hypoxia-mimicking conditions. These findings suggest that the effects of MIR100HG on oncogenic signaling are highly dependent on the cellular oxygenation context and that hypoxia reshapes the downstream signaling consequences of MIR100HG expression in HCC cells. Collectively, our findings identify MIR100HG as a hypoxia-associated oncogenic regulator that enhances tumorigenic phenotypes and promotes survival signaling in hepatocellular carcinoma. These results highlight MIR100HG as a potential biomarker and therapeutic target in liver cancer and provide new insights into the molecular mechanisms underlying hypoxia-driven tumor progression.

Humans

Eucalyptol mitigates isoproterenol-induced myocardial injury in rats via activation of p38 MAPK/JNK signaling, suppression of ER stress, and modulation of apoptotic pathway.

BACKGROUND: Myocardial injury (MI), a subset of cardiovascular diseases, remains a leading cause of deaths globally, driven by pathological inflammation, oxidative stress, and apoptosis. Despite advances in interventional cardiology, high relapse rates and therapeutic limitations underscore the urgent need for novel pharmacological agents. Phytochemicals, with their multi-target approach and favorable safety profiles, offer promising alternatives for mitigating ischemic injury. METHODS: The cardioprotective effects of 1,8-cineole, a monoterpene derived from Eucalyptus species, was investigated in a rat model of isoproterenol-induced myocardial injury. Serum levels of cardiac enzymes (creatine kinase (CK), lactate dehydrogenase (LDH)) and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) were quantified. Preliminary histopathological analysis was performed to assess the extent of myocardial damage. Key molecular mechanisms were evaluated via western blotting and immunohistochemistry, examining pathways related to inflammation (NF-κB), apoptosis (Bcl-2/Bax, caspase-3), endoplasmic reticulum (ER) stress (GRP78, CHOP, PERK-eIF2α), and antioxidant defense (GSH, SOD, CAT). RESULTS: Our results demonstrate that 1,8-cineole significantly reduced the levels of serum cardiac enzymes (CK-MB, LDH), and histopathological damage. Mechanistically, 1,8-cineole also suppressed pro-inflammatory cytokine release (TNF-α, IL-6, and IL-1β) via inhibition of the NF-κB pathway. Furthermore, it attenuated cardiomyocyte apoptosis by modulating Bcl-2/Bax expression and inhibiting caspase-3 activation. Additionally, 1,8-cineole alleviated ER stress by downregulating GRP78, CHOP, and PERK-eIF2α signaling. Importantly, we identified enhanced Nrf2 nuclear translocation and subsequent upregulation of antioxidant enzymes (GSH, SOD, CAT) as key contributors to its cytoprotective effects. CONCLUSIONS: 1,8-Cineole exhibits potent cardio-protection in experimental myocardial injury by targetinginflammation, apoptosis, ER stress, and oxidative stress through modulation of p38 MAPK/JNK, suppression of inflammatory markers (TNF-α, IL-6, IL-1β) and apoptotic markers (Bax, p53). Its natural origin, bioavailability, and multi-mechanistic effectiveness make it a promising candidate for translational development as an adjunct therapy for myocardial injury.

Animals

Impaired stem cell migration and divisions in Duchenne muscular dystrophy revealed by live imaging.

Dysregulation of stem cell properties is a hallmark of many pathologies, but the dynamic behaviour of stem cells in their microenvironment during disease progression remains poorly understood. Using the mdx mouse model of Duchenne Muscular Dystrophy, we developed innovative live imaging of muscle stem cells (MuSCs) in vivo, and ex vivo on isolated myofibres. We show that mdx MuSCs have impaired migration and precocious differentiation through unbalanced symmetric divisions, driven by p38 and PI3K signalling pathways, in contrast to the p38-only dependence of healthy MuSCs. Cross-grafting shows that MuSC fate decisions are governed by fibre-independent cues, whereas their migration behaviour is determined by the myofibre niche. This study provides the first dynamic analysis of dystrophic MuSC properties in vivo, reconciling conflicting reports on their function. Our findings establish DMD as a MuSC disease with niche dysfunctions, offering strategies to restore stem cell functions for improved muscle regeneration.

Stem Cells

Desmoplakin Mutations in Cardiac Fibroblasts Cause TGFβ1-Mediated Pathological Fibrogenesis in Desmoplakin Cardiomyopathy Via Beclin-1 Regulation.

BACKGROUND: Pathological fibrosis is a major finding in cardiovascular diseases and can result in arrhythmia and heart failure. Desmosome gene mutations can lead to arrhythmogenic cardiomyopathy. Among arrhythmogenic cardiomyopathies, pathogenic DSP (desmoplakin) variants cause a distinctive cardiomyopathy with excessive cardiac fibrosis that could precede ventricular dysfunction. DSP variants are also linked to other fibrotic diseases. Whether DSP plays any role in pathological fibrosis remains unknown. METHODS: Mesenchymal stromal cells (MSCs) are resident fibroblast-like cells that are responsible for fibrogenesis in most organs, including the heart. We first used RNA-seq genome-wide analyses to generate cardiac fibroblast-like, induced pluripotent stem cell-derived MSCs from normal donors and patients with arrhythmogenic cardiomyopathy and DSP mutations. We then studied the fibrogenic responses of cardiac MSCs to TGFβ1 (transforming growth factor β1) using Western/Co-IP, autophagy assays, gene knockdowns/over-expressions, genomic analyses, mouse DSP knockdown models, immunostaining, and qPCR. RESULTS: TGFβ1 induced excessive accumulation of VIM (vimentin)/fibrillar collagens and over-activated fibrotic genes in DSP-mutant MSCs when compared with normal MSCs. In normal MSCs, VIMs bind to wild-type DSP during normal fibrogenesis after TGFβ1. DSP-mutant MSCs exhibited a haplo-insufficient phenotype with increased DSP-unbound VIMs that sequestered BECN1 (beclin-1) from activating autophagy and CAV1 (caveolin-1)-mediated endocytosis. Decreased autophagy caused collagen accumulation, and diminished CAV1 endocytosis resulted in abnormal CAV1 plaque formation that over-activated fibrotic genes (COL1A1, COL3A1, and fibronectin [FN]) via heightened p38 activity after TGFβ1. Genome-wide analysis and DSP knockdown in mouse fibroblasts confirmed this novel role of DSP mutations in pathological fibrosis. Overexpression of VIM-binding domains of DSP could suppress pathological fibrosis by increasing collagen autophagic degradation and decreasing fibrotic gene expression. CONCLUSIONS: Our data reveal that DSP deficiency in MSCs/fibroblasts leads to exaggerated fibrogenesis in DSP-cardiomyopathy by decreasing BECN1 availability for autophagy and CAV1-endocytosis. Overexpression of VIM binding domains of DSP could be a new strategy to treat pathological fibrosis.

Animals

Molecular characterization of 16 MAPK genes in silver carp (Hypophthalmichthys molitrix) and the differences of their mRNA expression between Qiandao Lake and Taihu Lake.

Mitogen-activated protein kinase (MAPK), a serine-threonine protein kinase, is involved in a variety of stress-induced responses and also plays an important regulatory role in cell metabolism. In the study the open reading frames (ORFs) of 16 MAPK genes in silver carp (Hypophthalmichthys molitrix) were obtained and verified, with the evaluations of their taxonomy, structures, conserved motifs, and evolutionary linkages. And the expression patterns of these genes in the silver carp from Qiandao Lake and Taihu Lake were explored for better understanding the response of MAPK genes to different water environment. MAPK genes of silver carp were divided into three subfamilies, including extracellular signal-regulated kinase (ERK) subfamily, p38 subfamily and C-Jun N-terminal kinase (JNK) subfamily. All these genes possessed similar structures and conserved motifs of MAPK family. Realtime qPCR revealed that the expression patterns of 10 MAPK genes (ScMAPK1, ScMAPK3, ScMAPK4, ScMAPK7, ScMAPK15, ScMAPK8a, ScMAPK8b, ScMAPK9, ScMAPK10 and ScMAPK11) in head kidney, spleen and gill of silver carp in Taihu Lake and Qiandao Lake were different. These findings provide a basis for further research on the function of MAPK in silver carp.

Animals