Search Results (108)

Urokinase plasminogen activation system regulates the activation of plasminogen to produce the ubiquitous extracellular protease plasmin. It is involved in different physiological and pathophysiological processes, which involve tissue reorganization, wound healing, cell migration and invasion, etc. The system comprises urokinase plasminogen activator, an extracellular protease, its inhibitor plasminogen activator inhibitor PAI1 and urokinase receptor, uPAR. The system is regulated at the level of transcription and posttranscriptionally, and the net urokinase activity depends on the balance between urokinase and PAI1. Promoters of urokinase, PAI1 and uPAR are regulated through different signaling pathways, mostly MAP kinases and TGFβ signaling. Urokinase promoter is complex and mostly depends on strong enhancers containing AP1/ETS binding sites for different combinations of AP1 dimers, whose members are phosphorylated through ERK, JNK and p38 kinases. The PAI1 promoter is mainly regulated through TGFβ signaling, which can use both Smad and AP1-dependent transcription. The uPAR promoter also depends on AP1 signaling, in addition to other transcription factors activated through other pathways. Although activated through common pathways, each of the promoters has specific regulation as a consequence of a signaling network, which enables fine-tuning of the system and urokinase activity according to the physiological needs. Full article

Background/Objectives: Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the clonal proliferation of Langerhans-like dendritic cells and constitutive activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK-ERK) signaling pathway. Nearly 80% of ERK pathway activation can be attributed to B-Raf proto-oncogene, serine/threonine kinase (BRAF V600E), and mitogen-activated protein kinase kinase 1 (MAP2K1) variants, with BRAF V600E specifically detected in approximately 50% of pediatric LCH cases and associated with a higher risk of severe disease and treatment failure. The use of the HistioTrak clinical assay to detect the presence of BRAF V600E mutations in peripheral blood mononuclear cells (PBMCs) has emerged as a useful diagnostic tool and biomarker. Methods: This study is a single-center retrospective study that explores the favorable outcomes of treatment with trametinib on a small number of patients with LCH. We retrospectively analyzed the records of 11 children with LCH treated with trametinib at diagnosis as front-line therapy (n = 6), due to progressive disease (n = 3) or intolerance (n = 1) to chemotherapy, or at relapse (n = 1). Results: HistioTrak identified the presence of BRAF V600E PBMCs in five patients. In this small single-center retrospective cohort, trametinib was associated with favorable short-term outcomes in all patients, and serial HistioTrak testing appeared feasible in selected patients. Conclusions: Prospective studies are needed before routine diagnostic or monitoring use can be recommended. Full article

Mitogen-activated protein kinase kinase kinase 1 (MAP3K1) possesses dual enzymatic functions, i.e., kinase and E3 ubiquitin ligase activities, orchestrating proliferation, survival, apoptosis, DNA damage response, and immune modulation. Recent genomic and mechanistic studies have revealed MAP3K1’s paradoxical, context-dependent roles as both an oncogene and a tumor suppressor. We discuss MAP3K1’s multidomain architecture, featuring an N-terminal RING and PHD domain (E3 ligase activity), a TOG domain (microtubule dynamics), and a C-terminal kinase domain, enabling the integration of c-jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK), and nuclear factor kappa B (NF-κB) signaling pathways. MAP3K1 functions as a molecular switch balancing survival and apoptosis, with caspase-3 cleavage at Asp878 activating pro-apoptotic JNK/p38 signaling. Genomic analyses across >35 cancer types reveal MAP3K1 alterations at frequencies of <1–14%, highest in breast and endometrial cancers. These alterations show tissue specificity: loss-of-function mutations predominate in hormone receptor-positive breast cancer with a favorable prognosis, whereas gain-of-function mutations in melanoma activate oncogenic ERK signaling. MAP3K1 mutations predict response to mitogen-activated protein kinase kinase (MEK) and phosphoinositide 3-kinase (PI3K) inhibitors, with mutant cancers showing higher MEK inhibitor response than wild-type tumors. Despite substantial progress, critical gaps remain regarding MAP3K1’s E3 ligase substrates, context-dependent activity determinants, and therapeutic strategies. Addressing these through inhibitor development, biomarker validation, and mechanistic studies will accelerate potential clinical translation of MAP3K1 biology. Full article

Background/Objectives: Salidroside, a bioactive phenylethanol glycoside primarily derived from Rhodiola rosea, and its major in vivo metabolite tyrosol exhibit diverse pharmacological activities. However, their direct molecular targets remain poorly defined. Methods: In the present study, an integrated strategy combining transcriptomic profiling, Connectivity Map (CMap) analysis, and multi-level experimental validation was employed. Transcriptomic signatures derived from A549 cells treated with salidroside or tyrosol were queried against the CMap database. Molecular docking, surface plasmon resonance (SPR), and cellular thermal shift assays (CETSA) were performed to predict and validate binding interactions. Functional validation was performed in SH-SY5Y cells. The phosphorylation level of extracellular signal-regulated kinase (ERK), a downstream signaling event of dopamine D2 receptor (DRD2), was detected after salidroside and tyrosol treatment. DRD2 antagonist sulpiride pre-intervention and small interfering RNA (siRNA)-mediated DRD2 knockdown were conducted to verify the receptor dependence of the compounds’ effects. Results: CMap analysis revealed that the transcriptomic signatures of salidroside and tyrosol showed significant similarity to known DRD2 modulators. Molecular docking predicted potential binding interactions between the two compounds and DRD2, which was confirmed by SPR and CETSA to be direct physical binding. Functional studies showed that both compounds rapidly induced DRD2 downstream ERK phosphorylation in SH-SY5Y cells; this effect was abrogated by sulpiride or DRD2 knockdown, indicating DRD2-dependent signaling activation. Conclusions: These findings identify DRD2 as a direct molecular target of salidroside and tyrosol and provide mechanistic insight into their dopaminergic regulatory effects. This study highlights the utility of CMap-guided target discovery combined with rigorous experimental validation for elucidating the molecular mechanisms of natural products. Full article

This study sought to evaluate the neuroprotective effects of YGD in an oxidative stress-induced Alzheimer’s disease (AD)-like cellular model and to elucidate the underlying molecular pathways, with a focus on tau phosphorylation, Aβ accumulation, and antioxidant defense mechanisms. Rat primary hippocampal neurons were exposed to hydrogen peroxide to induce oxidative stress. The effects of YGD on neuronal viability, neurite outgrowth, and synaptic integrity were assessed using the immunodetection of microtubule-associated protein 2 (MAP2), postsynaptic density protein 95 (PSD-95), and synapsin-1. Levels of phosphorylated tau and Aβ were quantified, and the involvement of extracellular signal-regulated kinase (ERK), glycogen synthase kinase 3β (GSK3β), and nuclear factor-erythroid 2-related factor-2 (Nrf2) pathways was examined. Additionally, in silico molecular docking studies targeting the ATP-binding site of GSK3β were conducted to screen major phytochemicals from the ten medicinal herbs constituting YGD. YGD markedly enhanced neuronal viability under oxidative stress, promoted neurite extension, and increased synaptic marker expression (MAP2, PSD-95, and synapsin-1). Treatment reduced phosphorylated tau by suppressing ERK and GSK3β activation and significantly decreased Aβ accumulation. YGD also upregulated antioxidant defenses via the activation of the Nrf2 pathway. Docking simulations identified oleanolic acid (from Cornus officinalis) as the most potent GSK3β binder (−9.86 ± 0.40 kcal/mol), forming stable interactions with ARG96, ASN95, and GLU97. Additional compounds, including alisol C, drypemolundein B, and friedelin, demonstrated favorable binding energies and engaged key ATP-binding site residues. YGD confers neuroprotection through the integrated modulation of tau phosphorylation, Aβ pathology, and oxidative stress, partly via the multi-target engagement of GSK3β by its constituent phytochemicals. These findings support that YGD attenuates oxidative stress-induced AD-like cellular alterations. Full article

Melanogenesis, the key biological process underlying skin hyperpigmentation, is tightly regulated by complex molecular signaling pathways. Consequently, targeting molecular regulators of this pathway is a crucial strategy for developing effective skin-whitening agents. Cannabinol (CBN), a minor cannabinoid, has been largely unexplored owing to its role in modulating skin pigmentation. This study aimed to elucidate the molecular mechanisms of CBN’s depigmenting effects using an α-MSH-induced B16F10 melanoma cell model. High-purity CBN was obtained via conversion of cannabidiol (CBD) and confirmed by HPLC. CBN significantly inhibited melanin synthesis and tyrosinase activity in a concentration-dependent manner, without any cytotoxicity. Furthermore, we investigated CBN’s impact on the melanogenesis signaling cascade. Our analysis revealed that CBN significantly downregulated the mRNA and protein levels of key melanogenic master regulators, including MITF, TYR, TYRP1, and TYRP2. Importantly, we also observed that CBN treatment selectively suppressed the protein phosphorylation of upstream signaling molecules such as p38 and JNK MAP kinases and NF-κB, while ERK phosphorylation remained unaffected. This finding indicates that its mechanism of action involves the selective modulation of pro-melanogenic signaling components. Collectively, these findings demonstrate that CBN effectively modulates the melanogenesis signaling pathway by targeting both upstream kinases and downstream melanogenic genes. These findings suggest that CBN holds great promise as a bioactive agent for skin-whitening applications and warrants further research to confirm its clinical efficacy and safety. Full article

Background/Objectives: Guibi-tang (GBT) and its variant Kami-guibi-tang (KGBT) are traditional East Asian multi-herb formulas prescribed for memory loss, insomnia, and fatigue. Preclinical data suggest multimodal neuroprotective actions, including cholinergic signaling modulation and activation of the cAMP response element-binding protein (CREB)/extracellular signal-regulated kinase (ERK) pathway; however, clinical evidence for cognitive disorders remains scattered. This scoping review aimed to map the breadth, design characteristics, efficacy signals, and safety profile of GBT and KGBT across the full spectrum of cognitive impairment. Methods: Following the Arksey–O’Malley framework and PRISMA-ScR guidelines, seven databases were searched (MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure, ScienceON, Scopus, Citation Information by the National Institute of Informatics) from inception to 31 January 2025, for human studies evaluating GBT or KGBT in subjective cognitive decline, mild cognitive impairment (MCI), dementia, or post-stroke cognitive impairment (PSCI). Two reviewers independently screened, extracted, and charted data on study design, participants, interventions, outcomes, and adverse events. Results: Fifteen studies met the inclusion criteria—nine randomized controlled trials, one crossover trial, and five observational reports—enrolling 555 participants (age range, 59–87 years). All were conducted in the Republic of Korea, Japan, or China. GBT or KGBT, given as monotherapy or adjunctive therapy for 4 weeks to 9 months, produced modest but consistent improvements in global cognition (Mini-Mental State Examination/Montreal Cognitive Assessment), memory domains, activities of daily living, and neuropsychiatric symptoms across MCI, Alzheimer’s disease, and PSCI cohorts. Reported adverse event rates were comparable to or lower than those of placebo, usual care, or conventional drugs, and no serious treatment-related toxicity was identified. Conclusions: Current evidence—although limited by small sample sizes, heterogeneous formulations, short follow-up durations, and regional concentration—indicates that GBT and KGBT are well tolerated and confer clinically meaningful cognitive and functional benefits. Standardized, multicenter, placebo-controlled trials with biomarker end points are warranted to confirm long-term efficacy, clarify mechanisms, and guide integrative clinical use. Full article

ERK5, a member of the MAP kinase family, has been implicated in several cancer types due to its role in regulating cell proliferation, survival, and migration. In this study, structure-based virtual screening was employed, followed by cell assays, and molecular dynamics simulations to identify novel ERK5 inhibitors. A commercially available library of 1.6 million compounds was subjected to a three-stage docking process (HTVS, SP, and XP), using the docking module in Schrodinger Maestro, yielding 40 candidates with superior docking scores compared to the co-crystallized ligand. These compounds were then tested for antiproliferative activity using an MTT assay in A549 and H292 lung cancer cell lines. Among the hits, STK038175, STK300222, and GR04 showed significant activity with IC₅₀ values of ranging from 10 to 25 µM. Western blot analysis revealed that STK300222 at 50 µM reduced the phosphorylation of ERK5 downstream targets similarly to a known inhibitor, while wound healing assays confirmed a dose-dependent decrease in cell migration. Molecular dynamics simulations of 200 ns further demonstrated that all three compounds form stable complexes with ERK5 that are comparable to the co-crystallized ligand in 5BYZ. The MD simulations also revealed strong electrostatic and solvation interactions observed for STK300222 and GR04 particularly. Furthermore, by calculating the MM-GB/SA scores from the MD trajectories, the binding affinities of the three hits, along with the co-crystallized ligand in 5BYZ, were re-scored. Although the co-crystallized ligand had the highest MM-GB/SA score at −38.96 Kcal mol⁻¹, STK300222 had a comparable score of −35.45 Kcal mol⁻¹. These results highlight STK300222 and GR04 as promising candidates for further optimization and in vivo validation as ERK5 inhibitors. Full article

Janus kinase 2 (JAK2) inhibitors have gained regulatory approval for treating various human diseases. While the JAK2/signal tranducer and activator of transcription 3 (STAT3) pathway plays a role in tumorigenesis, JAK2/STAT3 inhibitors have shown limited therapeutic efficacy in triple-negative breast cancer (TNBC). In this study, we assessed the antiproliferative effects of clinically approved JAK2 inhibitors in TNBC cell lines (MDA-MB-231 and HS578T) using the MTT assay. Among the four JAK2 inhibitors evaluated (fedratinib, cerdulatinib, peficitinib, and filgotinib), fedratinib significantly inhibited the proliferation of TNBC cells with IC₅₀ values below 2 μM. Fedratinib also demonstrated superior efficacy in inhibiting long-term colony formation compared to other JAK2 inhibitors. Western blot analyses showed that fedratinib uniquely inhibits the phosphoinositide 3-kinase (PI3K)/AKT pathway and moderately affects the MAP kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway, in addition to targeting JAK2/STAT3 signaling. Moreover, fedratinib distinctly decreased MYC and cyclin D1 protein levels while inducing poly (ADP-ribose) polymerase (PARP) cleavage and apoptotic cell death more effectively than other JAK2 inhibitors. We next investigated the effects of simultaneously inhibiting JAK2/STAT3 together with the MEK/ERK or PI3K/AKT pathways, as well as the impact of triple pathway inhibition. Notably, combining ceduratinib with either cobimetinib (MEK inhibitor) and ipatasertib (AKT inhibitor) or trametinib (MEK inhibitor) and alpelisib (PI3K inhibitor) mimicked the effects of fedratinib on the cell proliferation, MYC and cyclin D1 suppression, and pro-apoptotic protein induction. These finding suggest that JAK2 inhibition enhances the anticancer effects of concurrent MEK/ERK and PI3K/AKT pathway inhibition, while JAK2 inhibition alone shows minimal efficacy in TNBC cells. Full article

Inflammatory Bowel Disease (IBD) is a group of chronic and recurrent inflammatory diseases characterized by prolonged inflammation of the intestinal tract. Although it has been proven that the immune system plays a crucial role in the pathogenesis of IBD, a defective intestinal epithelium is also responsible for chronic inflammation, hence causing an over-activation of the immune response. For this reason, a therapeutic approach that acts by improving impaired intestinal homeostasis could ensure a greater therapeutic efficacy in IBD. Mitogen-activated protein kinases (MAPKs) signaling pathways may be involved in the pathogenesis of IBD. It has been demonstrated that the inhibition of mitogen-activated protein kinase kinase 1 (MEK1) may be a potential treatment against IBD since it may restore the normal epithelial function and reduce apoptosis of intestinal epithelial cells (IECs). New therapeutic strategies are emerging including small molecules such as microRNAs (miRNAs). In this study, we aimed to demonstrate that miR-369-3p was able to modulate the MEK/ERK signaling pathway. As reported by in silico analysis, miR-369-3p was capable of pairing the 3’UTR of the MAP2K1 gene. In vitro analysis demonstrated that mimic transfection with miR-369-3p in epithelial cells downregulated the expression of MEK1, reduced the activation of ERK signaling, and modulated apoptosis of epithelial cells in response to TNF-α. Moreover, miR-369-3p significantly decreased the release of pro-inflammatory cytokine IL-8. These results support the potential of miR-369-3p to prevent apoptosis of IECs, responsible for a persistent inflammatory condition in IBD, highlighting its application value in the treatment of inflammatory disorders. Full article

In the present study, we investigated the anti-inflammatory and anti-melanogenic effects of Leuconostoc mesenteroides subsp. DB-21-derived exosomes (DB-21 exosomes), isolated from Camellia japonica flower in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells and melanocyte-stimulating hormone (α-MSH)-induced B16F10 melanoma cells. We confirmed that DB-21 exosomes were not toxic to LPS-induced RAW 264.7 macrophage cells and α-MSH-induced B16F10 melanoma cells. Moreover, we confirmed that DB-21 exosomes inhibit the pro-inflammatory cytokines IL-6, IL-1β, TNF-α, PGE₂, and the expression of inflammatory factors iNOS and COX-2. We also found that DB-21 exosomes have a concentration-dependent ability to inhibit melanin, TRP-1, TRP-2, tyrosinase, and MITF, which are factors involved in melanogenesis. Additionally, it inhibits the phosphorylation of Akt and GSK-3β, and MAP kinase pathway proteins such as ERK, JNK, and p38. We confirmed that DB-21 exosomes inhibit melanin synthesis in B16F10 cells through various pathways, and based on previous results, they may be used as a functional cosmetic material with anti-inflammatory and anti-melanogenic activities. Full article

Several lines of evidence have linked the intestinal bacterium Helicobacter cinaedi with the pathogenesis of atherosclerosis, identifying the Cinaedi Antigen Inflammatory Protein (CAIP) as a key virulence factor. Oxidative stress and inflammation are crucial in sustaining the atherosclerotic process and oxidized LDL (oxLDL) uptake. Primary human macrophages and endothelial cells were pre-incubated with 10 µM diphenyl iodonium salt (DPI) and stimulated with 20 µg/mL CAIP. Lectin-like oxLDL receptor (LOX-1) expression was evaluated by FACS analysis, reactive oxygen species (ROS) production was measured using the fluorescent probe H2DCF-DA, and cytokine release was quantified by ELISA assay. Foam cells formation was assessed by Oil Red-O staining, and phosphorylation of p38 and ERK1/2 MAP kinases and NF-κB pathway activation were determined by Western blot. This study demonstrated that CAIP triggered LOX-1 over-expression and increased ROS production in both macrophages and endothelial cells. Blocking ROS abrogated LOX-1 expression and reduced LDL uptake and foam cells formation. Additionally, CAIP-mediated pro-inflammatory cytokine release was significantly affected by ROS inhibition. The signaling pathway induced by CAIP-induced oxidative stress led to p38 MAP kinase phosphorylation and NF-κB activation. These findings elucidate the mechanism of action of CAIP, which heightens oxidative stress and contributes to the atherosclerotic process in H. cinaedi-infected patients. Full article

Chronic inflammation contributes to a number of diseases. Therefore, control of the inflammatory response is an important therapeutic goal. To identify novel anti-inflammatory compounds, we synthesized and screened a library of 80 pyrazolo[1,5-a]quinazoline compounds and related derivatives. Screening of these compounds for their ability to inhibit lipopolysaccharide (LPS)-induced nuclear factor κB (NF-κB) transcriptional activity in human THP-1Blue monocytic cells identified 13 compounds with anti-inflammatory activity (IC₅₀ < 50 µM) in a cell-based test system, with two of the most potent being compounds 13i (5-[(4-sulfamoylbenzyl)oxy]pyrazolo[1,5-a]quinazoline-3-carboxamide) and 16 (5-[(4-(methylsulfinyl)benzyloxy]pyrazolo[1,5-a]quinazoline-3-carboxamide). Pharmacophore mapping of potential targets predicted that 13i and 16 may be ligands for three mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase 2 (ERK2), p38α, and c-Jun N-terminal kinase 3 (JNK3). Indeed, molecular modeling supported that these compounds could effectively bind to ERK2, p38α, and JNK3, with the highest complementarity to JNK3. The key residues of JNK3 important for this binding were identified. Moreover, compounds 13i and 16 exhibited micromolar binding affinities for JNK1, JNK2, and JNK3. Thus, our results demonstrate the potential for developing lead anti-inflammatory drugs based on the pyrazolo[1,5-a]quinazoline and related scaffolds that are targeted toward MAPKs. Full article

Arrestins are known to be involved not only in the desensitization and internalization of G protein-coupled receptors but also in the G protein-independent activation of mitogen-activated protein (MAP) kinases, such as extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), to regulate cell proliferation and inflammation. Our previous study revealed that the histamine H₁ receptor-mediated activation of ERK is dually regulated by G_q proteins and arrestins. In this study, we investigated the roles of G_q proteins and arrestins in the H₁ receptor-mediated activation of JNK in Chinese hamster ovary (CHO) cells expressing wild-type (WT) human H₁ receptors, the G_q protein-biased mutant S487TR, and the arrestin-biased mutant S487A. In these mutants, the Ser487 residue in the C-terminus region of the WT was truncated (S487TR) or mutated to alanine (S487A). Histamine significantly stimulated JNK phosphorylation in CHO cells expressing WT and S487TR but not S487A. Histamine-induced JNK phosphorylation in CHO cells expressing WT and S487TR was suppressed by inhibitors against H₁ receptors (ketotifen and diphenhydramine), G_q proteins (YM-254890), and protein kinase C (PKC) (GF109203X) as well as an intracellular Ca²⁺ chelator (BAPTA-AM) but not by inhibitors against G protein-coupled receptor kinases (GRK2/3) (cmpd101), β-arrestin2 (β-arrestin2 siRNA), and clathrin (hypertonic sucrose). These results suggest that the H₁ receptor-mediated phosphorylation of JNK is regulated by G_q-protein/Ca²⁺/PKC-dependent but GRK/arrestin/clathrin-independent pathways. Full article

Hypertension is a global civilization disease and one of the most common causes of death in the world. Organ dysfunction is a serious health consequence of hypertension, which involves damage to the heart, kidneys and adrenals. The interaction of recently discovered multifunctional protein-CacyBP/SIP with ERK1/2 and p38 kinases by regulating the activity and intracellular localization of these kinases may play an important role in the signaling pathways involved in the pathogenesis of hypertension. Due to the lack of data on this subject, we decided to investigate the localization, expression and possible relationship between the studied parameters in the adrenals under arterial hypertension. The study was conducted on the adrenals of rats with spontaneous and DOCA-salt hypertension. The expression of CacyBP/SIP, p-ERK1/2 and p-p38 was detected by immunohistochemistry and qRT-PCR. The results show a statistically significant decrease in CacyBP/SIP expression in the adrenal glands of hypertensive rats. With ERK1/2, there was a decrease in cortical immunoreactivity and an increase in the adrenal medulla of primary hypertensive rats. In contrast, in the adrenals of DOCA-salt rats, ERK1/2 immunoreactivity increased in the cortex and decreased in the medulla. In turn, p38 expression was higher in the adrenal glands of rats with primary and secondary hypertension. The obtained results may suggest the involvement of CacyBP/SIP in the regulation of signaling pathways in which MAP kinases play an important role and provide new insight into molecular events in hypertension. Moreover, they show the participation of CacyBP/SIP in response to oxidative stress. Full article