Search Results (118)

Transforming growth factor-beta 1 (TGF-β1)-stimulated clone 22 domain (TSC22D) family genes (including TSC22D1-TSC22D4) were identified as transcription factors. It has been demonstrated that they display multiple functions due to proteins’ isoforms, redundancy, and other factors. Formerly, researchers mainly focused on its functions, like controlling cell growth and development, cell apoptosis, and balance of osmotic pressure in vivo. Nowadays, growing evidence indicates that they also play an important role in metabolic regulation and the immune system and are expected to be a new potential target for the treatment of diabetes or obesity. Despite this, it has been shown that TSC22D family genes have an inhibitory effect in multiple tumors. In this review, we significantly synthesized advances in metabolism, showing that TSC22D3 could control lipid accumulation via modulating adipogenesis and adipose differentiation, while TSC22D4 could regulate insulin sensitivity and gluconeogenesis by affecting Akt (serine/threonine kinase, also known as protein kinase B, or PKB) phosphorylation. Moreover, we provide novel insights, including the fact that TSC22D family genes function as a double-edged sword in cancer due to the type of tumor and tumor microenvironment (TME). Full article

Follicle selection is a pivotal process that determines which dominant prehierarchical follicle will enter the preovulatory hierarchy in the hen ovary and directly affects egg-laying productivity, in which granulosa cells (GCs) are characterized by active proliferation and significantly enhanced FSHR mRNA expression. Increasing evidence has shown that the PI3K/Akt signaling pathway and its important target and effector FOXO1, which promotes GC apoptosis, play crucial roles in ovarian follicular development in mammals. To investigate the molecular mechanism by which follicle-stimulating hormone (FSH)-mediated forkhead box O1 (FOXO1) participates in follicle selection, we treated granulosa cells from 6–8 mm prehierarchical follicles of chickens with FSH and leptomycin B (LMB). The results showed that under FSH and/or LMB treatment, the expression levels of FSHR, FOXO1, and its phosphorylated forms (p-FOXO1) at the predicted protein kinase B (PKB/Akt) phosphorylation sites Thr²⁴, Ser²⁴⁸, and Ser³¹¹ were differentially regulated. The subcellular localization of p-FOXO1 in hen ovarian GCs was determined by Western blotting and immunofluorescence staining (IF) analysis. And the expression of FOXO1 was significantly reduced, whereas the expression of p-FOXO1 corresponding to the PKB phosphorylation sites Ser²⁴⁸ and Ser³¹¹ was noticeably boosted in cultured GCs induced by FSH, accompanied by exclusion of FOXO1 from the nucleus to the cytoplasm. Subsequently, the effects of the PI3K/Akt signaling pathway on phosphorylation levels and nuclear exclusion of p-FOXO1 at the sites Ser²⁴⁸ and Ser³¹¹ were examined. The results indicate that the PI3K/Akt-dependent phosphorylation at these sites directly resulted in nuclear exclusion of FOXO1 in ovarian GCs, in which the Ser²⁴⁸ site is more essential than the Ser³¹¹ site. Subsequently, the FSH-induced acetylation of FOXO1 mediated by the cAMP/PKA pathway can enhance the phosphorylation level of FOXO1 at the Ser²⁴⁸ site. In summary, our findings demonstrate that FSH induces FOXO1 phosphorylation, nuclear exclusion, and functional inactivation by activating the PI3K/Akt signaling pathway. Moreover, during follicular development and selection, FOXO1 acts as a pivotal mediator linking the PI3K/Akt and P62/Keap1/Nrf2 signaling pathways to regulate granulosa cell proliferation and apoptosis, thereby exerting a central regulatory role. Full article

Acacetin, a naturally occurring flavonoid, has attracted increasing attention due to its broad anticancer potential. In vitro and in vivo studies using diverse tumor models have demonstrated that acacetin modulates oncogenic signaling, suppresses angiogenesis, and induces apoptosis and other regulated cell death pathways. With the rising demand for multi-target therapeutics, network pharmacology and molecular docking have emerged as powerful tools to unravel the complex molecular mechanisms of phytochemicals. Unlike previous reviews that have mainly focused on single pathways or limited cancer contexts, this review emphasizes novelty by integrating network pharmacology with molecular docking and explicitly linking these computational predictions to experimental validation, thereby identifying epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3), and the serine/threonine kinase AKT (also known as protein kinase B (PKB) as central experimentally supported targets. This integrative framework maps acacetin’s multi-target anticancer mechanisms and clarifies its translational opportunities for future therapeutic development. Full article

The regulation of T cell-mediated immune responses is essential for maintaining immune homeostasis and preventing autoimmune diseases. In multiple sclerosis (MS), impaired immunoregulatory control allows autoreactive T cells to persist, as effector T cells (Teff) display reduced susceptibility to regulatory T cells (Treg). This resistance to Treg-mediated tolerance is linked to altered IL-6 signaling and hyperactivation of protein kinase B (PKB/c-Akt). However, the mechanisms leading to increased PKB phosphorylation remain poorly understood. Here, we examined the expression of phosphatase and tensin homolog PTEN, a key phosphatase that negatively regulates PKB/c-Akt activation. We found that PTEN protein expression rapidly declines in activated Teff from MS patients. To clarify whether PTEN downregulation contributes to Treg resistance, we used PTEN-specific siRNA to modulate PTEN expression in Teff from healthy donors. PTEN knockdown resulted in accelerated IL-6 production, enhanced PKB phosphorylation, and reduced responsiveness to Treg-mediated suppression, similar to Treg resistance observed in MS. This study reports disrupted PTEN expression in activated Teff from MS patients. Our findings highlight that PTEN is critical for effective immune regulation of T cells, and suggest its dysregulation contributes to impaired immune tolerance in MS. Full article

Background/Objectives: Allergens can trigger severe immune responses in hypersensitive individuals, with mast cells releasing inflammatory mediators via IgE-FcɛRI signaling. Spleen tyrosine kinase (Syk) is a key regulator in this pathway, making it a promising therapeutic target. Natural modulators of Syk-mediated mast cell activation remain underexplored. This study investigated the anti-allergic effects of a 70% ethanol extract of Salvia miltiorrhiza (SME) using in vitro and in vivo models. Methods: SME was evaluated using IgE-sensitized RBL-2H3 cells, a passive cutaneous anaphylaxis model, and a DNCB-induced atopic dermatitis-like mouse model. Allergic responses were assessed via degranulation assays, histopathology, serum IgE levels, and the spleen index. Results: SME significantly inhibited mast cell degranulation by 44.4 ± 1.6% in RBL-2H3 cells at 100 µg/mL following 30 min of treatment compared to the untreated control. Western blot analysis demonstrated dose-dependent suppression of protein kinase B (PKB, also known as AKT), c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and spleen tyrosine kinase (Syk) phosphorylation, indicating inhibition of key allergic signaling pathways. In an IgE/Ag-induced passive cutaneous anaphylaxis model in ICR mice, SME (100 mg/kg, orally) significantly attenuated vascular permeability, as evidenced by a 20.6 ± 9.7% reduction in Evans blue extravasation relative to the Ag-treated group. In a 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis (AD)-like model, six treatments of SME significantly improved the skin condition, reduced spleen enlargement associated with allergic inflammation, and decreased serum IgE levels by 43.3 ± 11.2% compared to the DNCB group. Conclusions: These findings suggest that SME may help to alleviate allergic responses and AD by modulating key immune signaling pathways. Full article

Epithelial differentiation and function are tightly coupled to the keratin intermediate filament cytoskeleton. Keratin filaments are unique among the cytoskeletal filament systems in terms of biochemical properties, diversity and turnover mechanisms supporting epithelial plasticity in response to a multitude of environmental cues. Epidermal growth factor (EGF) is such a cue. It is not only intricately intertwined with epithelial physiology but also modulates keratin filament network organization by increasing keratin filament turnover. The involved EGF receptor (EGFR)-dependent intracellular signaling cascades, however, have not been identified to date. We therefore tested the effect of selective inhibitors of downstream effectors of the EGFR on keratin filament turnover using quantitative fluorescence recovery after photobleaching experiments as readouts. We find that SRC and ERK kinases are involved in the regulation of keratin filament turnover, whereas PI3K/AKT and FAK have little or no effect. The identification of SRC and ERK as major keratin filament regulators extends beyond EGF signaling since they are also activated by other signals and stresses. Our data unveil a mechanism that allows modification of the properties of keratin filaments at very high temporal and spatial acuity. Full article

As the primary active component of Astragalus membranaceus, Astragaloside IV (AS-IV) is widely recognized in pharmacological research for its multifaceted therapeutic potential, particularly its antioxidative, immunostimulatory, and cardioprotective properties. Oxidative stress is an important mechanism in the induction of many diseases. The present study investigates the antioxidative mechanism of Astragaloside IV in zebrafish, using menaquinone exposure to induce oxidative stress conditions. The findings revealed that AS-IV effectively attenuated oxidative stress-induced mortality and morphological abnormalities in zebrafish. AS-IV exhibited a concentration-dependent protective effect against developmental abnormalities, with progressive reduction in pericardial effusion, body curvature, and growth retardation observed at higher doses. Moreover, AS-IV treatment not only effectively reduced reactive oxygen species (ROS) accumulation and attenuated oxidative DNA damage but also significantly decreased apoptosis in the cardiac region of zebrafish embryos under oxidative stress conditions. Western blot analysis revealed that AS-IV treatment significantly reduced the protein levels of both Cleaved Caspase-3 and γ-H2AX, indicating its ability to inhibit DNA damage-induced apoptosis. AS-IV mediates its antioxidant defense mechanisms through the activation of the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway, inducing the significant upregulation of cytoprotective enzymes. This molecular mechanism underlies the observed phenotypic improvements in oxidative stress-related damage. Upstream analysis demonstrated that AS-IV activates NRF2 primarily through protein kinase B (AKT/PKB) pathway modulation, independent of KEAP1 regulation. Comprehensive mechanistic analysis reveals that Astragaloside IV mitigates oxidative stress-induced apoptosis in zebrafish through coordinated regulation of the AKT/NRF2/HO-1/Caspase-3 signaling axis. Full article

Receptor-mediated endocytosis (RME) is a commonly recognized receptor internalization process of receptor degradation or recycling. However, recent studies have supported that RME is closely related to signal propagation and amplification from the plasma membrane to the cytosol. Few studies have elucidated the role of H₂O₂, a mild oxidant among reactive oxygen species (ROS) in RME and second messenger of signal propagation. In the present study, we investigated the regulatory function of H₂O₂ in early endosomes during signaling throughout receptor-mediated endocytosis. In mammalian cells with a physiological amount of H₂O₂ generated during epidermal growth factor (EGF) activation, fluorescence imaging showed that the levels of two activating phosphorylations on Ser⁴⁷³ and Thr³⁰⁸ of Akt were transiently increased in the plasma membrane, but the predominant p-Akt on Ser⁴⁷³ appeared in early endosomes. To examine the role of endosomal H₂O₂ molecules as signaling mediators of Akt activation in endosomes, we modulated endosomal H₂O₂ through the ectopic expression of an endosomal-targeting catalase (Cat-Endo). The forced removal of endosomal H₂O₂ inhibited the Akt phosphorylation on Ser⁴⁷³ but not on Thr³⁰⁸. The levels of mSIN and rictor, two components of mTORC2 that work as a kinase in Akt phosphorylation on Ser⁴⁷³, were also selectively diminished in the early endosomes of Cat-Endo-expressing cells. We also observed a decrease in the endosomal level of the adaptor protein containing the PH domain, the PTB domain, and the Leucine zipper motif 1 (APPL1) protein, which is an effector of Rab5 and key player in the assembly of signaling complexes regulating the Akt pathway in Cat-Endo-expressing cells compared with those in normal cells. Therefore, the H₂O₂-dependent recruitment of the APPL1 adaptor protein into endosomes was required for full Akt activation. We proposed that endosomal H₂O₂ is a promoter of Akt signaling. Full article

The Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP1) is a multidomain protein consisting of two protein–protein interaction domains, the Src homology 2 (SH2) domain, and the proline-rich region (PRR), as well as three phosphoinositide-binding domains, the pleckstrin homology-like (PHL) domain, the 5-phosphatase (5PPase) domain, and the C2 domain. SHIP1 is commonly known for its involvement in the regulation of the PI3K/AKT signaling pathway by dephosphorylation of phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P₃) at the D5 position of the inositol ring. However, the functional role of each domain of SHIP1 for the regulation of its enzymatic activity is not well understood. To determine the contribution of the individual domains to catalytic activity, the full-length protein was compared with truncated constructs lacking one or more domain(s), regarding the substrate turnover (k_cat) and catalytic efficiency (k_cat/K_m) towards ci8-PtdIns(3,4,5)P₃. With this approach, it was possible to verify the allosteric activation of SHIP1 mediated by the C2 domain as described previously, while the PHL domain seemed instead to have a negative effect regarding catalytic efficiency. The full-length SHIP1 clearly displayed the highest turnover and the second-highest catalytic efficiency, showing the role of the SH2 domain and PRR not only in protein–protein interactions but also in catalysis. The SH2 domain increased substrate turnover but negatively affected catalytic efficiency. The linker between the SH2 and the PHL domains decreased the turnover number but positively influenced the catalytic efficiency. The PRR increased both the substrate turnover and the protein’s catalytic efficiency. The regression analysis of the Michaelis–Menten graph revealed SHIP1 to be an allosteric enzyme, with the PRR and the linker being the most involved domains in that regard. In summary, our data indicate a complex regulation of the enzymatic activity of SHIP1 by its individual domains. While the C2 domain and PRR at the carboxy-terminus have a positive effect on enzymatic activity, the SH2 and PHL domain at the amino-terminus inhibit catalytic efficiency. Full article

Type 2 diabetes mellitus (T2DM) is a chronic disease characterized by insulin resistance and impaired beta-cell secretory function. Since existing treatments often present side effects based on different mechanisms, alternative therapeutic options are needed. In this scenario, the present study first evaluates the cytotoxicity of decoctions from the leaves, stems, and roots of Cucumis prophetarum L. on HepG2 and L6C5 cells. The extracts were chemically investigated by UV–Vis and ATR-FTIR spectroscopic techniques and by ultra high-performance chromatographic techniques, coupled with high-resolution mass spectrometry. Briefly, decoctions from the leaves and stems were mainly composed of apigenin C-glycosides, while the root decoction was rich in raffinose and cucumegastigmane II. To evaluate the insulin-sensitizing properties of the extracts in insulin-resistant L6 myoblasts, an evaluation by Western blot analysis of the proteins in the insulin signaling pathway was then performed. Particularly, key proteins of insulin signaling were investigated, i.e., insulin receptor substrate (IRS-1), protein kinase B (PKB/AKT), and glycogen synthase kinase-3 (GSK-3β), which have gained considerable attention from scientists for the treatment of diabetes. Under all conditions tested, the three decoctions showed low cytotoxicity. The stem and root decoction (300 μg/mL) resulted in a significant increase in the levels of p-IRS-1 (Tyr612), GSK3β (Ser9), and p-AMPK (Thr172) compared to those of the palmitic acid-treated group, and the leaf decoction resulted an increase in the level of p-IRS-1 (Tyr612) and p-AMPK (Thr172) and a decrease in p-GSK3β (Ser9) compared to the levels for the palmitic acid-treated group. The root decoction also reduced the level of p-mToR (Ser2448). Overall, the acquired data demonstrate the effect of reducing insulin resistance induced by the investigated decoctions, opening new scenarios for the evaluation of these effects aimed at counteracting diabetes and related diseases in animal models. Full article

Isoscopoletin is a compound derived from various plants traditionally used for the treatment of skin diseases. However, there have been no reported therapeutic effects of isoscopoletin on atopic dermatitis (AD). AD is a chronic inflammatory skin disease, and commonly used treatments have side effects; thus, there is a need to identify potential natural candidate substances. In this study, we aimed to investigate whether isoscopoletin regulates the inflammatory mediators associated with AD in TNF-α/IFN-γ-treated HaCaT cells and PMA/ionomycin treated RBL-2H3 cells. We determined the influence of isoscopoletin on cell viability through an MTT assay and investigated the production of inflammatory mediators using ELISA and RT-qPCR. Moreover, we analyzed the transcription factors that regulate inflammatory mediators using Western blots and ICC. The results showed that isoscopoletin did not affect cell viability below 40 μM in either HaCaT or RBL-2H3 cells. Isoscopoletin suppressed the production of TARC/CCL17, MDC/CCL22, MCP-1/CCL2, IL-8/CXCL8, and IL-1β in TNF-α/IFN-γ-treated HaCaT cells and IL-4 in PMA/ionomycin-treated RBL-2H3 cells. Furthermore, in TNF-α/IFN-γ-treated HaCaT cells, the phosphorylation of signaling pathways, including MAPK, NF-κB, STAT, and AKT/PKB, increased but was decreased by isoscopoletin. In PMA/ionomycin-treated RBL-2H3 cells, the activation of signaling pathways including PKC, MAPK, and AP-1 increased but was decreased by isoscopoletin. In summary, isoscopoletin reduced the production of inflammatory mediators by regulating upstream transcription factors in TNF-α/IFN-γ-treated HaCaT cells and PMA/ionomycin-treated RBL-2H3 cells. Therefore, we suggest that isoscopoletin has the potential for a therapeutic effect, particularly in skin inflammatory diseases such as AD, by targeting keratinocytes and basophils. Full article

This narrative review aims to examine the therapeutic potential and mechanism of action of plant extracts in preventing and treating alopecia (baldness). We searched and selected research papers on plant extracts related to hair loss, hair growth, or hair regrowth, and comprehensively compared the therapeutic efficacies, phytochemical components, and modulatory targets of plant extracts. These studies showed that various plant extracts increased the survival and proliferation of dermal papilla cells in vitro, enhanced cell proliferation and hair growth in hair follicles ex vivo, and promoted hair growth or regrowth in animal models in vivo. The hair growth-promoting efficacy of several plant extracts was verified in clinical trials. Some phenolic compounds, terpenes and terpenoids, sulfur-containing compounds, and fatty acids were identified as active compounds contained in plant extracts. The pharmacological effects of plant extracts and their active compounds were associated with the promotion of cell survival, cell proliferation, or cell cycle progression, and the upregulation of several growth factors, such as IGF-1, VEGF, HGF, and KGF (FGF-7), leading to the induction and extension of the anagen phase in the hair cycle. Those effects were also associated with the alleviation of oxidative stress, inflammatory response, cellular senescence, or apoptosis, and the downregulation of male hormones and their receptors, preventing the entry into the telogen phase in the hair cycle. Several active plant extracts and phytochemicals stimulated the signaling pathways mediated by protein kinase B (PKB, also called AKT), extracellular signal-regulated kinases (ERK), Wingless and Int-1 (WNT), or sonic hedgehog (SHH), while suppressing other cell signaling pathways mediated by transforming growth factor (TGF)-β or bone morphogenetic protein (BMP). Thus, well-selected plant extracts and their active compounds can have beneficial effects on hair health. It is proposed that the discovery of phytochemicals targeting the aforementioned cellular events and cell signaling pathways will facilitate the development of new targeted therapies for alopecia. Full article

Ginkgo biloba L. (ginkgo) is a widely used medicinal plant around the world. Its leaves, which have been used as a traditional Chinese medicine, are rich in various bioactive components. However, most of the research and applications of ginkgo leaves have focused on terpene trilactones and flavonol glycosides, thereby overlooking the other active components. In this study, a lipophilic extract (GL) was isolated from ginkgo leaves. This extract is abundant in lipids and lipid-like molecules. Then, its effect and potential mechanism on glucose uptake and insulin resistance in C2C12 myotubes were investigated. The results showed that GL significantly enhanced the translocation of GLUT4 to the plasma membrane, which subsequently promoted glucose uptake. Meanwhile, it increased the phosphorylation of AMP-activated protein kinase (AMPK) and its downstream targets. Both knockdown of AMPK with siRNA and inhibition with AMPK inhibitor compound C reversed these effects. Additionally, GL ameliorated palmitate-induced insulin resistance by enhancing insulin-stimulated glucose uptake, increasing the phosphorylation of protein kinase B (PKB/AKT), and restoring the translocation of GLUT4 from the cytoplasm to the membrane. However, pretreatment with compound C abolished these beneficial effects of GL. In conclusion, GL enhances basal glucose uptake in C2C12 myotubes and improves insulin sensitivity in palmitate-induced insulin resistant myotubes through the AMPK pathway. Full article

Protein kinase B (PKB) or AKT protein is an important target for cancer treatment. Significant advances have been made in developing ATP-competitive inhibitors and allosteric binders targeting AKT1. However, adverse effects or toxicities have been found, and the cutaneous toxicity was found to be linked to the inhibition of AKT2. Thus, selective inhibition of AKT inhibitors is of significance. Our work, using the Schrödinger Covalent Dock (CovDock) program and the Movable Type (MT)-based free energy calculation (ΔG), yielded small mean errors for the experimentally derived binding free energy (ΔG). The docking data suggested that AKT1 binding may require residues Asn54, Trp80, Tyr272, Asp274, and Asp292, whereas AKT2 binding would expect residues Phe163 and Glu279, and AKT3 binding would favor residues Glu17, Trp79, Phe306, and Glu295. These findings may help guide AKT1-selective or AKT3-selective molecular design while sparing the inhibition of AKT2 to minimize the cutaneous toxicity. Full article

Type 2 diabetes mellitus (T2DM) accounts for one-sixth of deaths globally, whereas cancer is the second leading cause of death in the U.S. T2DM is a known risk factor for many cancers. Reactive oxygen species (ROS)-altered metabolic and signaling pathways link T2DM to cancer. These reprogrammed metabolic and signaling pathways contribute to diabetic complications, impact the redox balance (oxidative stress), and have differential roles in the early and late stages of cancer. A respiratory chain that is highly reduced (as under hyperglycemic conditions) or if reduced cofactors accumulate, ROS are greatly elevated. ROS may cause mutations in mitochondrial DNA (mtDNA) that result in further ROS elevations. The amplification of ROS results in the activation of PKC, an overarching signaling pathway that activates MAPK with a subsequent regulation in several factors that result in pathophysiological manifestations of T2DM and cancer. An upregulation in PKC leads to a deregulation in NF-kß, which regulates the PKB/P13/Akt pathway and orchestrates the cell survival, growth, proliferation, and glucose metabolism manifested in cancer. It also affects Insulin Receptor Substrate (IRS-1), decreasing insulin-stimulated glucose transport and glucose uptake, disrupting subsequent cell signaling pathways contributing to the development of T2DM. Dyslipidemia is a hallmark of T2DM and cancer. ROS-induced lipid peroxidation leads to systemic inflammation, producing inflammatory prostaglandins, cytokines, and chemokines that result in tumor proliferation, rapid tumor growth, and modulation of immunity. The dual role of ROS in the early and late stages of cancer makes antioxidant therapy precarious and may be responsible for controversial results. A system that delivers an antioxidant directly to mitochondria may be useful in inhibiting the formation of ROS early during the pre-diabetic stage, whereas antioxidant therapy must be halted in later stages to retard metastasis. Full article