Search Results (3,019)

The aim of this study was to analyze how recombinant rabbit NGF (Nerve Growth Factor) encapsulated in chitosan (rrβNGFch) affects sperm viability, motility, capacitation, acrosome reaction (AR), kinetic traits, and apoptosis after 30 min and 2 h of storage. Specific intracellular signaling pathways associated with either cell survival, such as protein kinase B (AKT) and extracellular signal-regulated kinases 1/2 (ERK1/2), or programmed cell death, such as c-Jun N-terminal kinase (JNK), were also analyzed. The results confirmed the effect of rrβNGFch on capacitation and AR, whereas a longer storage time (2 h) decreased all qualitative sperm traits. AKT and JNK did not show treatment-dependent activation and lacked a correlation with functional traits, as shown by ERK1/2. These findings suggest that rrβNGFch may promote the functional activation of sperm cells, particularly during early incubation. The increase in capacitation and AR was not linked to significant changes in pathways related to cell survival or death, indicating a specific action of the treatment. In contrast, prolonged storage negatively affected all sperm parameters. ERK1/2 activation correlated with capacitation, AR, and apoptosis, supporting its role as an NGF downstream mediator. Further studies should analyze other molecular mechanisms of sperm and the potential applications of NGF in assisted reproduction. Full article

The Sprouty (Spry) proteins modulate signalling and regulate processes like cellular migration and proliferation. Here, we investigated a Spry4 alteration substituting a lysine at position 177 to an arginine, based on a mutation found in Kallmann syndrome, a genetically heterogeneous disease connected to reduced fibroblast growth factor receptor1 (FGFR) signalling. Using growth curves to evaluate proliferative and scratch assays to determine migrative capacities of the cells, in normal fibroblasts as well as in osteosarcoma-derived cells, we demonstrate that the modified Spry4^K177R version hinders both processes, which the unaltered protein cannot do under the same conditions. The inhibition of these processes was accompanied by lower relative phospho-extracellular-signal-regulated kinases (pERK) levels in response to serum induction, indicating that activation of MAPK was less efficient. In contrast to the situation in these cells of mesenchymal origin, in lung cancer-derived cell lines both variants of Spry4 were able to interfere with proliferation of tested cells, and in the cells with elevated FGFR1 expression the Spry4 proteins with an alteration at codon 177 were even more effective. In summary, these data indicate that the lysine at position 177 restricts the ability of Spry4 to inhibit signal transduction at least in cells with high FGFR1 levels. Full article

Osteoclastogenesis—the activation and differentiation of osteoclasts—is one of the pivotal processes of bone remodeling and is regulated by RANKL/RANK signaling, the decoy function of osteoprotegerin (OPG), and a cascade of pro- and anti-inflammatory cytokines. The disruption of this balance leads to pathological bone loss in diseases such as osteoporosis and rheumatoid arthritis. FFAR4 (Free Fatty Acid Receptor 4), a G protein-coupled receptor for long-chain omega-3 fatty acids, has been confirmed as a key mediator of metabolic and anti-inflammatory effects. This review focuses on how FFAR4 acts as the selective receptor for the omega-3 fatty acid docosahexaenoic acid (DHA). It activates two divergent signaling pathways. The Gαq-dependent cascade facilitates intracellular calcium mobilization and ERK1/2 activation. Meanwhile, β-arrestin-2 recruitment inhibits NF-κB. These collective actions reshape the cytokine environment. In macrophages, DHA–FFAR4 signaling lowers the levels of TNF-α, interleukin-6 (IL-6), and IL-1β while increasing IL-10 secretion. Consequently, the activation of NFATc1 and NF-κB p65 is profoundly suppressed under TNF-α or RANKL stimulation. Additionally, DHA modulates the RANKL/OPG axis in osteoblastic cells by suppressing RANKL expression, thereby reducing osteoclast differentiation in an inflammatory mouse model. Full article

Prolactin (PRL) is a hormone primarily associated with lactation, but it plays various roles in both men and women. PRL belongs to the family of peptide hormones, including placental lactogen and growth hormone. Interestingly, PRL is a pleiotropic hormone affecting several physiological and pathological conditions, including fertility. Moreover, several pathophysiological roles have been associated with this hormone, including those of the immune system, autoimmune disorders, asthma, and ageing. Additionally, PRL receptors are ubiquitously expressed in tissues, including the mammary gland, gonads, liver, kidney, adrenal gland, brain, heart, lungs, pituitary gland, uterus, skeletal muscle, skin blood cells, and immune system. Therefore, in the present paper, we cover the potential role that PRL may play in asthma by promoting inflammation and modulating immune responses. The detection of its receptor in lung tissue suggests a direct role in airway smooth muscle contractility through activation of signaling pathways such as JAK2-STAT5, MAPK/ERK1/2, and PI3K/Akt, as well as influencing ionic currents that regulate cell contraction, proliferation, and survival. In this sense, this review aims to explore the potential involvement of PRL in asthma pathophysiology by examining its interactions with intracellular signaling pathways and its possible impact on airway smooth muscle contractility and immune modulation. Full article

Cell proliferation plays a pivotal role in multiple physiological processes, including osteoporosis alleviation, wound healing, and immune enhancement. Numerous novel peptides with cell proliferation-promoting activity have been identified. These peptides exert their functions by modulating key cellular signaling pathways, thereby regulating diverse biological processes related to cell proliferation. This work summarizes peptides derived from animals and plants that stimulate cell proliferation, focusing on their amino acid composition, physicochemical properties, and preparation techniques. Furthermore, we highlight the major signaling pathways—such as the PI3K/Akt, MAPK/ERK, and Wnt/β-catenin pathways—that have been implicated in the mechanistic studies of food-derived peptides. Through the analysis and summary of previous studies, we observe a notable lack of in vivo animal models and clinical trials, indicating that these may represent promising directions for future research on food-derived bioactive peptides. Meanwhile, the potential safety concerns of proliferation-enhancing peptides—such as immunogenicity, appropriate dosage, and gastrointestinal stability—warrant greater attention. In summary, this review provides a comprehensive overview of the sources and mechanisms of cell proliferation-promoting peptides and addresses the challenges in industrializing bioactive peptide-based functional foods; therefore, further research in this area is encouraged. Full article

Drug resistance remains a critical barrier to effective treatment in several cancers, particularly triple-negative breast cancer (TNBC). Estrogen receptor α36 (ERα36), a variant of the estrogen receptor in ER-negative breast cancer cells, plays important roles in cancer cell proliferation. We investigated the role of ERα36 in regulating multidrug resistance protein 1 (MDR1) in MDA-MB-231 human breast cancer cells. The activation of ERα36 by BSA-conjugated estradiol (BSA-E2) increased cell viability under Adriamycin exposure, suggesting its involvement in promoting drug resistance. BSA-E2 treatment significantly reduced the intracellular rhodamine-123 levels by activating the MDR1 efflux function, which was linked to increased MDR1 transcription and protein expression. The mechanical ERα36-mediated BSA-E2-induced activation of EGFR and downstream signaling via c-Src led to an activation of the Akt/ERK pathways and transcription factors, NF-κB and CREB. Additionally, ERα36 is involved in activating Wnt/β-catenin pathways to induce MDR1 expression. The silencing of ERα36 inhibited the BSA-E2-induced phosphorylation of Akt and ERK, thereby reducing MDR1 expression via downregulation of NF-κB and CREB as well as Wnt/β-catenin signaling. These findings demonstrated that ERα36 promotes MDR1 expression through multiple non-genomic signaling cascades, including Akt/ERK-NF-κB/CREB and Wnt/β-catenin pathways, and highlight the role of ERα36 as a promising target to enhance chemotherapeutic efficacy in TNBC. Full article

Equine lutropin hormone/choriogonadotropin receptor (LH/CGR) is a G protein-coupled receptor that binds to both luteinizing hormone and choriogonadotropin, with multiple potential N-linked glycosylation sites in the long extracellular domain region. The roles of these glycosylation sites in hormone binding have been widely studied; however, their relationships with cyclic adenosine monophosphate (cAMP) activation, loss of cell surface receptors, and phosphorylated extracellular signal-regulated kinases1/2 (pERK1/2) expression are unknown. We used site-directed mutagenesis with the substitution of Asn for Gln to alter the consensus sequences for N-linked glycosylation, and cAMP signaling was analyzed in the mutants. Specifically, the N174Q and N195Q mutants exhibited markedly reduced expression levels, reaching approximately 15.3% and 2.5%, respectively, of that observed for wild-type equine LH/CGR. Correspondingly, the cAMP EC₅₀ values were decreased by 7.6-fold and 5.6-fold, respectively. Notably, the N195Q mutant displayed an almost complete loss of cAMP activity, even at high concentrations of recombinant eCG, suggesting a critical role for this glycosylation site in receptor function. Despite these alterations, Western blot analysis revealed that pERK1/2 phosphorylation peaked at 5 min following agonist stimulation across all mutants, indicating that the ERK1/2 signaling pathway remains functionally intact. This study demonstrates that the specific N-linked glycosylation site, N195, in equine LH/CGR is indispensable for cAMP activity but is normally processed in pERK1/2 signaling. Thus, we suggest that in equine LH/CGR, agonist treatment induces biased signaling, differentially activating cAMP signaling and the pERK1/2 pathway. Full article

B-raf (rapidly accelerated fibrosarcoma) is a crucial player within the ERK/MAPK signaling pathway. In the CNS, B-raf has been implicated in neuronal differentiation, long-term memory, and major depression. Mice with forebrain neuron-specific B-raf knockout show behavioral deficits in spatial learning tasks and impaired hippocampal long-term potentiation (LTP). To elucidate the mechanism(s) underlying diminished synaptic plasticity in B-raf-deficient mice, we performed whole-cell recordings from CA1 pyramidal cells in hippocampal slices of control and B-raf mutant mice. We found that the NMDA/AMPA ratio of excitatory postsynaptic currents (EPSCs) at the Schaffer collateral—CA1 pyramidal cell synapses was significantly reduced in B-raf mutants, which would at least partially account for their impaired LTP. Interestingly, the reduced NMDA component of field postsynaptic potentials in mutant preparations was partially reinstated by blocking the apamin-sensitive small-conductance Ca²⁺-activated K⁺ (SK) channels, which have also been reported to modulate hippocampal LTP and learning tasks. To determine the impact of B-raf-dependent signaling on SK current, we isolated the apamin-sensitive tail current after a strong depolarizing event and found indeed a significantly bigger SK current in B-raf-deficient cells compared to controls, which is consistent with the reduced action potential firing and the stronger facilitating effect of apamin on CA1 somatic excitability in B-raf-mutant hippocampus. Our data suggest that B-raf signaling readjusts the delicate balance between NMDA receptors and SK channels to promote synaptic plasticity and facilitate hippocampal learning and memory. Full article

Human coronaviruses are a group of viruses that continue to threaten human health. In this study, we investigated the antiviral activity of 4-hydroxychalcone (4HCH), a chalcone derivative, against human coronavirus HCoV-OC43. We found that 4HCH significantly inhibited the cytopathic effect, reduced viral protein and RNA levels in infected cells, and increased the survival rate of HCoV-OC43-infected suckling mice. Mechanistically, 4HCH targets the early stages of viral infection by binding to the epidermal growth factor receptor (EGFR) and inhibiting the EGFR/AKT/ERK1/2 signaling pathway, thereby suppressing viral replication. Additionally, 4HCH significantly reduced the production of pro-inflammatory cytokines and chemokines in both HCoV-OC43-infected RD cells and a suckling mouse model. Our findings demonstrate that 4HCH exhibits potent antiviral activity both in vitro and in vivo, suggesting its potential as a therapeutic agent against human coronaviruses. This study highlights EGFR as a promising host target for antiviral drug development and positions 4HCH as a candidate for further investigation in the treatment of coronavirus infections. Full article

Naturally occurring prostaglandin E₂ (PGE₂) influences cytokine production regulation in bovine neutrophils exposed to Staphylococcus aureus Rosenbach. Here, we employed bovine neutrophils as the primary experimental system, and administered specific inhibitors targeting various receptors, which were subsequently exposed to S. aureus. Cytokine expression levels in dairy cow neutrophils induced by S. aureus via the endogenous PGE₂-EP2/4 receptor pathway were investigated, and its effects on P38, extracellular signal-regulated kinase (ERK), P65 activation, and phagocytic function in Staphylococcus aureus Rosenbach-induced dairy cow neutrophils, were examined. Blocking cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) enzymes substantially decreased PGE₂ production and release in S. aureus-exposed bovine neutrophils. Cytokine output showed significant reduction compared to that in SA113-infected controls. Phosphorylation of P38, ERK, and P65 signaling molecules was depressed in the infected group. Pharmacological interference with EP2/EP4 receptors similarly diminished cytokine secretion and phosphorylation patterns of P38, ERK, and P65, with preserved cellular phagocytic function. During S. aureus infection of bovine neutrophils, COX-2 and mPGES-1 participated in controlling PGE₂ biosynthesis, and internally produced PGE₂ molecules triggered NF-κB and MAPK inflammatory pathways via EP2/EP4 receptor activation, later adjusting the equilibrium between cytokine types that promote or suppress inflammation. This signaling mechanism coordinated inflammatory phases through receptor-mediated processes. Full article

Glucocorticoids (GCs), such as dexamethasone (DEX), are commonly administered to glioblastoma (GBM) patients to control cerebral edema; however, their effects on immune checkpoint regulation in tumor cells remain insufficiently characterized. This study examined the impact of DEX on the expression of programmed death-ligand 1 (PD-L1) and glucocorticoid-induced leucine zipper (GILZ), a downstream effector of glucocorticoid receptor (GR) signaling, in the U87 and U251 glioblastoma cell lines. DEX consistently induced GILZ expression in both models yet elicited divergent effects on PD-L1: suppression in U87 cells and upregulation in U251 cells. In U87 cells, DEX-induced PD-L1 downregulation was accompanied by accelerated cell cycle progression, suggesting a dual impact on tumor immune evasion and proliferation. Mechanistically, GILZ silencing restored ERK phosphorylation and reversed PD-L1 suppression, whereas GILZ overexpression further decreased PD-L1 levels, implicating a GILZ–ERK pathway in the control of PD-L1. These findings uncover a previously unrecognized GR–GILZ–PD-L1 regulatory axis in glioblastoma cells. While these results are based on in vitro models, they provide a rationale for future in vivo studies to determine whether modulation of GILZ may influence immune checkpoint dynamics and therapeutic responsiveness in GBM. Full article

This study investigated the changes in protein composition and DNA content in damaged somatic nerves when exposed to insulin-like growth factor-1 (IGF-1). Using electrophoretic protein separation in polyacrylamide gel (PAG) and spectrophotometry, the transection was shown to be accompanied by a significant decrease in the quantitative content of total protein, certain protein fractions and DNA, both in the proximal and distal segments of the nerve conductor. Against the background of the intramuscular administration of IGF-1, intensive DNA synthesis and the protein composition stabilization of somatic nerves at the earlier post-traumatic stages were observed. By means of Raman scattering (RS-spectroscopy) and recording action potentials (APs), the enhanced recovery of the physicochemical condition of the nerve fiber membrane and its functional activity, indicating regeneration activation in the somatic nerves after damage, was revealed. IGF-1 was most likely to stimulate cytoskeleton protein synthesis through launching the mitogen-activated protein kinase signal pathway (MAPK/ERK), resulting in the increased expression of the genes related to the remyelination and functioning recovery of damaged nerve conductors. Full article

This review highlights recent findings on the potent anti-angiogenic serpin protein, pigment epithelium-derived factor (PEDF) as it relates to metabolic disease, diabetes, angiogenesis and cardiovascular disease (CVD), listing a majority of all the publicly available studies reported to date. PEDF is involved in various physiological roles in the body, and when awry, it triggers various disease states clinically. Biomarkers such as insulin, AMP-activated protein kinase alpha (AMPK-α), and peroxisome proliferator-activated receptor gamma (PPAR-γ) are involved in PEDF effects on metabolism. Wnt, insulin receptor substate (IRS), Akt, extracellular signal-regulated kinase (ERK), and mitogen-activated protein kinase (MAPK) are implicated in diabetes effects displayed by PEDF. For CVD, oxidised LDL, Wnt/β-catenin, and reactive oxygen species (ROS) are players intertwined with PEDF activity. The review also presents an outlook on where efforts could be devoted to bring this serpin closer to clinical trials for these diseases and others in general. Full article

Piperine, a phytochemical alkaloid, exhibits notable anticancer properties in several cancer cell types. In this study, we investigated the mechanisms by which piperine induces cell death and apoptosis in colorectal cancer (CRC) cells, focusing on oxidative stress and key signaling pathways. Using MTT assay, flow cytometry, gene overexpression, and Western blot analysis, we observed that piperine significantly reduced cell viability, triggered G1 phase cell cycle arrest, and promoted apoptosis in DLD-1 cells. In addition, piperine effectively suppressed cell viability and induced apoptosis in other CRC cell lines, including SW480, HT-29, and Caco-2 cells. These effects were associated with increased intracellular reactive oxygen species (ROS) generation, mediated by the regulation of mitochondrial complex III, NADPH oxidase, and xanthine oxidase. Additionally, piperine modulated signaling pathways by inhibiting phosphoinositide 3-kinase (PI3K)/Akt, activating p38 and p-extracellular signal-regulated kinase (ERK). Pretreatment with antimycin A, apocynin, allopurinol, and PD98059, and the overexpression of p-Akt significantly recovered cell viability and reduced apoptosis, confirming the involvement of these pathways. This study is the first to demonstrate piperine induces apoptosis in CRC cells through a multifaceted oxidative stress mechanism and by critically modulating PI3K/Akt and ERK signaling pathways. Full article

Tempol is a synthetic antioxidant that shows promise in preclinical cancer studies by inhibiting growth and inducing apoptosis. Given that the Mitogen-Activated Protein Kinase (MAPK) and Protein Kinase B/Mammalian Target of Rapamycin (Akt/mTOR) signaling pathways are frequently dysregulated in gastric and colon cancers and contribute to their progression, we investigated Tempol’s anti-cancer potential in HT29 (colon) and CRL-1739 (gastric) cancer cells. Cells were treated with 2 mM Tempol for 48 h, with untreated cells as controls. We evaluated apoptosis (Bax, cleaved caspase-3, and Bcl-2), key signaling pathway activity (p-ERK, p-JNK, p-AKT, and p-mTOR), and levels of stress- and apoptosis-related proteins (WEE1, GADD153, GRP78, and AIF). Tempol significantly increased pro-apoptotic Bax and cleaved caspase-3 (p < 0.0001) and decreased anti-apoptotic Bcl-2 (p < 0.0001) in both cell lines. Furthermore, Tempol markedly reduced the activity of p-ERK, p-JNK, p-AKT, and p-mTOR (p < 0.0001) and significantly increased the protein levels of WEE1, GADD153, GRP78, and AIF (p < 0.0001). Tempol treatment also led to a significant increase in total oxidant status and a decrease in total antioxidant status. In conclusion, our findings suggest that Tempol exhibits its anti-cancer activity through multiple interconnected mechanisms, primarily inducing apoptosis and oxidative stress, while concurrently suppressing pro-survival signaling pathways. These results highlight Tempol’s potential as a therapeutic agent for gastric and colon cancers. Full article