Recombinant human growth hormone promotes wound angiogenesis in burned mice through the ERK signaling pathway.

Burns are the most severe type of trauma, and the resulting ischemia and hypoxia damage can promote the dysfunction and even failure of tissues and organs throughout the body, endangering patients' life safety. Recombinant human growth hormone (rhGH) has the functions of promoting protein synthesis to reverse negative nitrogen balance, accelerating wound healing, and improving immune function, which is widely used in the treatment of burns. However, the exact mechanism and pathway of rhGH's action is not yet fully understood. In this study, we observed the wound repair effect of recombinant human growth hormone (rhGH) on burned mice and further analyzed the mechanism of action, which can provide more comprehensive reference opinions for clinical practice. First, by establishing a burn mouse model and and intervening with different doses of rhGH, we found that the wound healing capacity of mice was significantly enhanced and the inflammatory and oxidative stress responses were obviously alleviated, confirming the excellent promotion of wound repair and anti-inflammatory and antioxidant effects of rhGH. Subsequently, we found that the expression of p-ERK1/2/ERK1/2, EGF, TGF-ß, and VEGF proteins was elevated in the traumatic tissues of mice after rhGH intervention, suggesting that the pathway of action of rhGH might be related to the activation of ERK pathway to promote the regeneration of traumatic capillaries.

Increasing the radiation-induced cytotoxicity by silver nanoparticles and docetaxel in prostate cancer cells.

BACKGROUND: Radiation therapy is utilized for treatment of localized prostate cancer. Nevertheless, cancerous cells frequently develop radiation resistance. While higher radiation doses have not always been effective, radiosensitizers have been extensively studied for their ability to enhance the cytotoxic effects of radiation. So, this study aims to evaluate the possible radiosensitization effects of docetaxel (DTX) and silver nanoparticles (SNP) in LNCaP cells. METHODS: The cytotoxic effects of DTX, SNP and 2 Gy of X-Ray radiation treatments were assessed in human LNCaP cell line using the MTT test after 24 h. Moreover, the effects of DTX, SNP and radiation on Epidermal growth factor (EGF), Caspase 3, inducible nitric oxide synthase and E-cadherin gene expression were analyzed using the Real-time PCR method. The level of Hydrogen peroxide (H2O2), an oxidative stress marker, was also detected 24 h after various single and combined treatments. RESULTS: The combinations of SNP (in low toxic concentration) and/or DTX (0.25× IC50 and 0.5 × IC50 concentrations for triple and double combinations respectively) with radiation induced significant cytotoxicity in LNCaP cells in comparison to monotherapies. These cytotoxic effects were associated with the downregulation of EGF mRNA. Additionally, H2O2 levels increased after Radiation + SNP + DTX triple combination and double combinations including Radiation + SNP and Radiation + DTX versus single treatments. The triple combination treatment also increased Caspase 3 and and E-cadherin mRNA levels in compared to single treatments in LNCaP cells. CONCLUSION: Our results indicate that the combination of SNP and DTX with radiation induces significant anti-cancer effects. Upregulation of Caspase 3 and E-cadherin gene expression, and decreased mRNA expression level of EGF may be exerted specifically by use of this combination versus single treatments.

The Invasion Factor ODZ1 Is Upregulated through an Epidermal Growth Factor Receptor-Induced Pathway in Primary Glioblastoma Cells.

We have previously shown that the transmembrane protein ODZ1 promotes cytoskeletal remodeling of glioblastoma (GBM) cells and invasion of the surrounding parenchyma through the activation of a RhoA-ROCK pathway. We also described that GBM cells can control the expression of ODZ1 through transcriptional mechanisms triggered by the binding of IL-6 to its receptor and a hypoxic environment. Epidermal growth factor (EGF) plays a key role in the invasive capacity of GBM. However, the molecular mechanisms that enable tumor cells to acquire the morphological changes to migrate out from the tumor core have not been fully characterized. Here, we show that EGF is able to induce the expression of ODZ1 in primary GBM cells. We analyzed the levels of the EGF receptor (EGFR) in 20 GBM primary cell lines and found expression in 19 of them by flow cytometry. We selected two cell lines that do or do not express the EGFR and found that EGFR-expressing cells responded to the EGF ligand by increasing ODZ1 at the mRNA and protein levels. Moreover, blockade of EGF-EGFR binding by Cetuximab, inhibition of the p38 MAPK pathway, or Additionally, the siRNA-mediated knockdown of MAPK11 (p38ß MAPK) reduced the induction of ODZ1 in response to EGF. Overall, we show that EGF may activate an EGFR-mediated signaling pathway through p38ß MAPK, to upregulate the invasion factor ODZ1, which may initiate morphological changes for tumor cells to invade the surrounding parenchyma. These data identify a new candidate of the EGF-EGFR pathway for novel therapeutic approaches.

EGF-like growth factors upregulate pentraxin 3 expression in human granulosa-lutein cells.

The epidermal growth factor (EGF)-like factors, comprising amphiregulin (AREG), betacellulin (BTC), and epiregulin (EREG), play a critical role in regulating the ovulatory process. Pentraxin 3 (PTX3), an essential ovulatory protein, is necessary for maintaining extracellular matrix (ECM) stability during cumulus expansion. The aim of this study was to investigate the impact of EGF-like factors, AREG, BTC, and EREG on the expression and production of PTX3 in human granulosa-lutein (hGL) cells and the molecular mechanisms involved. Our results demonstrated that AREG, BTC, and EREG could regulate follicular function by upregulating the expression and increasing the production of PTX3 in both primary (obtained from 20 consenting patients undergoing IVF treatment) and immortalized hGL cells. The upregulation of PTX3 expression was primarily facilitated by the activation of the extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling pathway, induced by these EGF-like factors. In addition, we found that the upregulation of PTX3 expression triggered by the EGF-like factors was completely reversed by either pretreatment with the epidermal growth factor receptor (EGFR) inhibitor, AG1478, or knockdown of EGFR, suggesting that EGFR is crucial for activating the ERK1/2 signaling pathway in hGL cells. Overall, our findings indicate that AREG, BTC, and EREG may modulate human cumulus expansion during the periovulatory stage through the upregulation of PTX3.

Effect of collagen sponge combined with epidermal growth factor in repairing maxillofacial head and neck wounds in rats.

Collagen sponge and epidermal growth factor (EGF) promote wound healing. However, the effect of collagen sponge combined with EGF in repairing maxillofacial head and neck wounds remains unclear. The rats were divided into 3 groups, including experimental group 1 (Vaseline gauze+EGF), experimental group 2 (collagen sponge+EGF) with control group (Vaseline+normal saline), and maxillofacial head and neck wounds were simulated. Wound pathological morphology was detected by HE staining; wound EGF, IL-1ß, IL-6 along with TNF-α contents by ELISA and MMP1 level by western blot. At 7 and 14 days after treatment, wound healing rate of two experimental groups was higher than that of control group, and that of experimental group 2 presented higher than that of experimental group 1. Compared with control group, experimental group 1 had significantly fewer inflammatory cells in the wound tissue, local erythrocyte spillage outside the vascular walls, more collagen deposition and more granulation tissue. Compared with experimental group 1, inflammatory cells in wound tissues of experimental group 2 were significantly reduced, the collagen tissues were visible and arranged, and the growth of the wound granulation tissue was obvious. IL-1ß, IL-6 along with TNF-α levels in two experimental groups presented lower than control group, and EGF level was higher. More importantly, in contrast to experimental group 1, IL-1ß, IL-6 along with TNF-α in experimental group 2 presented lower, and EGF level presented higher. At 14 days after treatment, MMP1 level in two experimental groups was lower than control group. In contrast to experimental group 1, MMP1 level in experimental group 2 was lower. In summary, collagen sponge combined with EGF for the first time significantly improved the healing speed of maxillofacial head and neck wounds and reduced the scar left after wound healing.

The combined effect of epidermal growth factor and keratinocyte growth factor delivered by hyaluronic acid hydrogel on corneal wound healing.

This study strategically incorporates epidermal growth factor (EGF) and keratinocyte growth factor (KGF) within a hyaluronic acid (HA) hydrogel to enhance corneal wound healing. The controlled release of EGF and KGF from the HA hydrogel is engineered to promote the regeneration of both the epithelial and stromal layers. Specifically, EGF plays a pivotal role in the regeneration of the epithelial layer, while KGF exhibits efficacy in the regeneration of the stromal layer. The combination of these growth factors facilitates efficient regeneration of each layer and demonstrates the capability to modulate each other's regenerative effects. The interplay between EGF and KGF provides an understanding of their cooperative influence on the dynamics of corneal wound healing. The results of this study contribute to the development of advanced strategies for corneal wound management and offer insights into the complex process of corneal regeneration.

Overexpression of PTPN21 promotes proliferation of EGF-stimulated acute lymphoblastic leukemia cells via the MAPK signaling pathways.

OBJECTIVES: This study aims to investigate the role of excessive Protein Tyrosine Phosphatase Non-Receptor Type 21 (PTPN21) in the proliferation of Acute Lymphoblastic Leukemia (ALL) cells with EGF stimulation. METHODS: PTPN21 was overexpressed in ALL cell lines by lentiviral transfection. Apoptosis was assayed by Annexin V/7-AAD staining. The proliferation and cell cycle of EGF-treated ALL cells were assessed by MTT and Ki-67/7-AAD staining respectively. The phosphorylation of Src tyrosine kinase and mediators of distinct MAPK pathways were assessed by Western blot. RESULTS: Overexpression of PTPN21 had minimal effect on the apoptosis of ALL cells, but significantly promoted the proliferation and cell cycle progression of ALL cells stimulated with EGF. The activity of Src tyrosine kinase and the MAPK pathways was elevated. Inhibition of MAPK pathways by specific inhibitors mitigated this pro-proliferative effect of excessive PTPN21 on EGF-stimulated ALL cells. CONCLUSION: PTPN21 may facilitate ALL progression by promoting cell proliferation via the Src/MAPK signaling pathways.

Efficacy of recombinant human epidermal growth factor in pressure injury healing: evidence from Chinese randomized controlled trials.

OBJECTIVE: To evaluate the efficacy of recombinant human epidermal growth factor (rhEGF) in healing pressure injuries (PIs). METHODS: A meta-analysis was conducted of randomized controlled trials (RCTs) involving rhEGF in the treatment of PIs that were identified in PubMed, Web of Science, the Cochrane Library, and China National Knowledge Infrastructure (CNKI). The population, intervention, comparison, outcomes, study design (PICOS) strategy was applied to determine analysis eligibility. The Cochrane risk of bias tool was used, and statistical analysis, including sensitivity analysis, was performed of 3 outcomes indicators: the primary outcome was total efficacy of rhEGF in treating PIs, and the secondary outcomes were the proportion of complete healing and the time to complete healing. Total efficacy refers to the proportion of cases that have been cured, obviously effective, or effective. Complete healing refers to cases where the wound has healed, scabbed, and the scab has sloughed off. RESULTS: Sixteen RCTs were included, comprising a total of 1,206 patients. Study and control group size varied by outcomes. The total effective healing rate in rhEGF group was 97.18%, which was significantly higher than 83.38% in control group (OR: 5.69, [95% CI: 3.61, 8.97], z=7.49, P < .001). The proportion of complete healing in the rhEGF group was 73.30%, which was higher than 39.52% in control group (OR: 3.88, [95% CI: 3.01, 5.01], z=10.39, P < .001). Furthermore, the healing time using rhEGF was shorter (SMD: -2.14 days, [95% CI: -2.60, -1.67], z=9.07, P < .001). Sensitivity analyses indicated that the results were robust. CONCLUSIONS: The meta-analysis indicated that rhEGF was effective in healing PIs with few negative effects. Further research beyond Chinese populations involving larger studies and studies that distinguish between results found in using rhEGF alone or in combination are recommended.

A cleavable peptide adapter augments the activity of targeted toxins in combination with the glycosidic endosomal escape enhancer SO1861.

BACKGROUND: Treatment with tumor-targeted toxins attempts to overcome the disadvantages of conventional cancer therapies by directing a drug's cytotoxic effect specifically towards cancer cells. However, success with targeted toxins has been hampered as the constructs commonly remain bound to the outside of the cell or, after receptor-mediated endocytosis, are either transported back to the cell surface or undergo degradation in lysosomes. Hence, solutions to ensure endosomal escape are an urgent need in treatment with targeted toxins. In this work, a molecular adapter that consists of a cell penetrating peptide and two cleavable peptides was inserted into a targeted toxin between the ribosome-inactivating protein dianthin and the epidermal growth factor. Applying cell viability assays, this study examined whether the addition of the adapter further augments the endosomal escape enhancement of the glycosylated triterpenoid SO1861, which has shown up to more than 1000-fold enhancement in the past. RESULTS: Introducing the peptide adapter into the targeted toxin led to an about 12-fold enhancement in the cytotoxicity on target cells while SO1861 caused a 430-fold increase. However, the combination of adapter and glycosylated triterpenoid resulted in a more than 4300-fold enhancement and in addition to a 51-fold gain in specificity. CONCLUSIONS: Our results demonstrated that the cleavable peptide augments the endosomal escape mediated by glycosylated triterpenoids while maintaining specificity. Thus, the adapter is a promising addition to glycosylated triterpenoids to further increase the efficacy and therapeutic window of targeted toxins.

Effect of rmEGF combined with ELF-EMF on promoting wound healing in rats.

BACKGROUND: The process of wound healing is complex, and expediting it remains a challenge. The advantages of extremely low frequency electric and magnetic fields (ELF-EMF) are its non-invasive treatment, promotes healing and promotes myogenesis of C2C12 cells. Epidermal growth factor (EGF) is known to play a vital role in promoting wound healing, so a combination of ELF-EMF and EGF can have far-reaching significance. OBJECTIVE: To study the effect of recombinant murine epidermal growth factor (rmEGF) combined with ELF-EMF on wound healing. METHODS: Thirty-six rats were randomly divided into three groups: normal control group, EGF group, and ELF-EMF+EGF group, and a 20 mm × 20 mm dorsal wound was made. The wound healing rate of rats was calculated on the 3rd, 7th, 11th and 15th day. HE staining was used to observe the micro-morphological changes during the wound healing process. RESULTS: The wound healing rate of EGF+ELF-EMF group was better than other groups. On the 15th day of wound healing, the wounds of each group were completely healed. On the 3rd, 7th, 11th and 15th day of HE staining, the early inflammatory cell infiltration, the arrangement of fibroblasts and the number of new capillaries in the wounds of EGF+ELF-EMF group were better than those of the other groups. CONCLUSIONS: rmEGF combined with ELF-EMF significantly promotes wound healing in SD rats.

ATP2B4 is an essential gene for epidermal growth factor-induced macropinocytosis in A431 cells.

Macropinocytosis (MPC) is a large-scale endocytosis pathway that involves actin-dependent membrane ruffle formation and subsequent ruffle closure to generate macropinosomes for the uptake of fluid-phase cargos. MPC is categorized into two types: constitutive and stimuli-induced. Constitutive MPC in macrophages relies on extracellular Ca2+ sensing by a calcium-sensing receptor. However, the link between stimuli-induced MPC and Ca2+ remains unclear. Here, we find that both intracellular and extracellular Ca2+ are required for epidermal growth factor (EGF)-induced MPC in A431 human epidermoid carcinoma cells. Through investigation of mammalian homologs of coelomocyte uptake defective (CUP) genes, we identify ATP2B4, encoding for a Ca2+ pump called the plasma membrane calcium ATPase 4 (PMCA4), as a Ca2+-related regulator of EGF-induced MPC. Knockout (KO) of ATP2B4, as well as depletion of extracellular/intracellular Ca2+, inhibited ruffle closure and macropinosome formation, without affecting ruffle formation. We demonstrate the importance of PMCA4 activity itself, independent of interactions with other proteins via its C-terminus known as a PDZ domain-binding motif. Additionally, we show that ATP2B4-KO reduces EGF-stimulated Ca2+ oscillation during MPC. Our findings suggest that EGF-induced MPC requires ATP2B4-dependent Ca2+ dynamics.

Growth factor-induced activation of MSK2 leads to phosphorylation of H3K9me2S10 and corresponding changes in gene expression.

Extracellular signals are transmitted through kinase cascades to modulate gene expression, but it remains unclear how epigenetic changes regulate this response. Here, we provide evidence that growth factor-stimulated changes in the transcript levels of many responsive genes are accompanied by increases in histone phosphorylation levels, specifically at histone H3 serine-10 when the adjacent lysine-9 is dimethylated (H3K9me2S10). Imaging and proteomic approaches show that epidermal growth factor (EGF) stimulation results in H3K9me2S10 phosphorylation, which occurs in genomic regions enriched for regulatory enhancers of EGF-responsive genes. We also demonstrate that the EGF-induced increase in H3K9me2S10ph is dependent on the nuclear kinase MSK2, and this subset of EGF-induced genes is dependent on MSK2 for transcription. Together, our work indicates that growth factor-induced changes in chromatin state can mediate the activation of downstream genes.

Activation of epidermal growth factor receptors in triple-negative breast cancer cells by morphine; analysis through Raman spectroscopy and machine learning.

Triple negative breast cancer (TNBC) is a very aggressive form of breast cancer, and the analgesic drug morphine has been shown to promote the proliferation of TNBC cells. This article investigates whether morphine causes activation of epidermal growth factor receptors (EGFR), the roles of µ-opioid and EGFR receptors on TNBC cell proliferation and migration. While examining the changes with molecular techniques, we also aimed to investigate the analysis ability of Raman spectroscopy and machine learning-based approach. Effects of morphine on the proliferation and migration of MDA.MB.231 cells were evaluated by MTT and scratch wound-healing tests, respectively. Morphine-induced phosphorylation of the EGFR was analyzed by western blotting in the presence and absence of µ-receptor antagonist naltrexone and the EGFR-tyrosine kinase inhibitor gefitinib. Morphine-induced EGFR phosphorylation and cell migration were significantly inhibited by pretreatments with both naltrexone and gefitinib; however, morphine-increased cell proliferation was inhibited only by naltrexone. While morphine-induced changes were observed in the Raman scatterings of the cells, the inhibitory effect of naltrexone was analyzed with similarity to the control group. Principal component analysis (PCA) of the Raman confirmed the epidermal growth factor (EGF)-like effect of morphine and was inhibited by naltrexone and partly by gefitinib pretreatments. Our in vitro results suggest that combining morphine with an EGFR inhibitor or a peripherally acting opioidergic receptor antagonist may be a good strategy for pain relief without triggering cancer proliferation and migration in TNBC patients. In addition, our results demonstrated the feasibility of the Raman spectroscopy and machine learning-based approach as an effective method to investigate the effects of agents in cancer cells without the need for complex and time-consuming sample preparation. The support vector machine (SVM) with linear kernel automatically classified the effects of drugs on cancer cells with ∼95% accuracy.

Epidermal growth factor receptor (EGFR) is a target of the tumor-suppressor E3 ligase FBXW7.

FBXW7 is an E3 ubiquitin ligase that targets proteins for proteasome-mediated degradation and is mutated in various cancer types. Here, we use CRISPR base editors to introduce different FBXW7 hotspot mutations in human colon organoids. Functionally, FBXW7 mutation reduces EGF dependency of organoid growth by ~10,000-fold. Combined transcriptomic and proteomic analyses revealed increased EGFR protein stability in FBXW7 mutants. Two distinct phosphodegron motifs reside in the cytoplasmic tail of EGFR. Mutations in these phosphodegron motifs occur in human cancer. CRISPR-mediated disruption of the phosphodegron motif at T693 reduced EGFR degradation and EGF growth factor dependency. FBXW7 mutant organoids showed reduced sensitivity to EGFR-MAPK inhibitors. These observations were further strengthened in CRC-derived organoid lines and validated in a cohort of patients treated with panitumumab. Our data imply that FBXW7 mutations reduce EGF dependency by disabling EGFR turnover.

Regulation of STAT1 and STAT4 Expression by Growth Factor and Interferon Supplementation in Sjögren's Syndrome Cell Culture Models.

Our goal was to investigate the effects of epidermal growth factor (EGF) and interferons (IFNs) on signal transducer and activator of transcription STAT1 and STAT4 mRNA and active phosphorylated protein expression in Sjögren's syndrome cell culture models. iSGECs (immortalized salivary gland epithelial cells) and A253 cells were treated with EGF, IFN-alpha, -beta, -gamma, or mitogen-activated protein kinase p38 alpha (p38-MAPK) inhibitor for 0-24-48-72 h. STAT1 and STAT4 mRNA expression was quantified by qRT-PCR. Untreated and treated cells were compared using the delta-delta-CT method based on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) normalized relative fold changes. phospho-tyrosine-701-STAT1 and phospho-serine-721-STAT4 were detected by Western blot analysis. STAT4 mRNA expression decreased 48 h after EGF treatment in A253 cells, immortalized salivary gland epithelial cells iSGECs nSS2 (sicca patient origin), and iSGECs pSS1 (anti-SSA negative Sjögren's Syndrome patient origin). EGF and p38-MAPK inhibitor decreased A253 STAT4 mRNA levels. EGF combined with IFN-gamma increased phospho-STAT4 and phospho-STAT1 after 72 h in all cell lines, suggesting additive effects for phospho-STAT4 and a major effect from IFN-gamma for phospho-STAT1. pSS1 and nSS2 cells responded differently to type I and type II interferons, confirming unique functional characteristics between iSGEC cell lines. EGF/Interferon related pathways might be targeted to regulate STAT1 and STAT4 expression in salivary gland epithelial cells. Further investigation is required learn how to better target the Janus kinases/signal transducer and activator of transcription proteins (JAK/STAT) pathway-mediated inflammatory response in Sjögren's syndrome.

Cholesterol suppresses spontaneous activation of EGFR-mediated signal transduction.

Epidermal growth factor receptor (EGFR)-mediated signal transduction controls cell growth and proliferation. The signaling pathway is regulated so that it is activated only by external EGF stimuli, but the mechanisms that prevent EGF-independent spontaneous activation of EGFR-mediated signaling are unknown. Here we report cholesterol depletion activates EGFR-mediated signaling without EGF. We applied automated single-molecule imaging to EGFR and characterized the lateral diffusion and cluster formation on cholesterol-depleted and cholesterol-supplemented membranes. In cells in which cholesterol was depleted by methyl-ß-cyclodextrin (MßCD) treatment, EGFR exhibited a reduction in lateral diffusion, an acceleration of cluster formation, and autophosphorylation without EGF. Concurrently, extracellular signal-regulated kinase (ERK), which is regulated by EGFR-mediated signaling, exhibited phosphorylation and nuclear translocation without EGF. These cholesterol depletion-induced changes were similar, albeit less efficient, to those that occurred with EGF stimulation in normal cells without MßCD, indicating the spontaneous activation of EGFR signaling. The exogenous supplementation of cholesterol suppressed the MßCD-induced spontaneous activation of EGFR and ERK nuclear translocation. Single-molecule imaging of EGFR in a large number of cells revealed cell-to-cell heterogeneity, with a sub-population showing a high ability for spontaneous activation. These results provide evidence that EGFR-mediated signaling is properly regulated by cholesterol metabolism to prevent uncontrolled spontaneous activation.

TCM formula for trauma treatment screening and its role of promoting infectious wound coalescence investigating.

In pet clinics, the number of cases using trauma drugs accounts for >10% of the total number of cases, and most wounds are healing by second intention. The prolongation of wound healing time causes inconvenience and burden to pets and pet owners. Therefore, how to reduce wound healing time and achieve maximum recovery of tissue function and aesthetics is one of the focuses of veterinary clinical practice. Wound suppuration caused by Staphylococcus aureus and Pseudomonas aeruginosa is the main cause of delaying wound healing. Clinically, available antimicrobial treatments are almost exhausted due to the production of large numbers of resistant bacteria. At present, there are no bacteria resistant to traditional Chinese medicine (TCM), which makes TCM have the potential to become an effective drug for the treatment of bacterial infections, so the use of TCM in the treatment of traumatic infections has broad prospects. Based on the characteristics of infection syndrome, three different prescriptions were formulated in our laboratory, and the most effective prescription and dosage form was screened and named Lianrong Healing Cream (LRHC). The results showed that LRHC regulated the expression of fibroblast growth factor-2 (FGF-2), epidermal growth factor-1 (EGF-1), transforming growth factor-ß (TGF-ß) and vascular endothelial growth factor-1 (VEGF-1) genes in wound tissues and fibroblasts, thereby accelerating wound healing and repairing wound appearance and function. The results of this study may be help to develop TCM formulation for traumatic infections.

Searching for EGF Fragments Recreating the Outer Sphere of the Growth Factor Involved in Receptor Interactions.

The aims of this study were to determine whether it is possible to use peptide microarrays obtained using the SPOT technique (immobilized on cellulose) and specific polyclonal antibodies to select fragments that reconstruct the outer sphere of proteins and to ascertain whether the selected peptide fragments can be useful in the study of their protein-protein and/or peptide-protein interactions. Using this approach, epidermal growth factor (EGF) fragments responsible for the interaction with the EGF receptor were searched. A library of EGF fragments immobilized on cellulose was obtained using triazine condensing reagents. Experiments on the interactions with EGFR confirmed the high affinity of the selected peptide fragments. Biological tests on cells showed the lack of cytotoxicity of the EGF fragments. Selected EGF fragments can be used in various areas of medicine.

Epidermal Growth Factor Suppresses the Development of GABAergic Neurons Via the Modulation of Perineuronal Net Formation in the Neocortex of Developing Rodent Brains.

Previously, we reported that epidermal growth factor (EGF) suppresses GABAergic neuronal development in the rodent cortex. Parvalbumin-positive GABAergic neurons (PV neurons) have a unique extracellular structure, perineuronal nets (PNNs). PNNs are formed during the development of PV neurons and are mainly formed from chondroitin sulfate (CS) proteoglycans (CSPGs). We examined the effect of EGF on CSPG production and PNN formation as a potential molecular mechanism for the inhibition of inhibiting GABAergic neuronal development by EGF. In EGF-overexpressing transgenic (EGF-Tg) mice, the number of PNN-positive PV neurons was decreased in the cortex compared with that in wild-type mice, as in our previous report. The amount of CS and neurocan was also lower in the cortex of EGF-Tg mice, with a similar decrease observed in EGF-treated cultured cortical neurons. PD153035, an EGF receptor (ErbB1) kinase inhibitor, prevented those mentioned above excess EGF-induced reduction in PNN. We explored the molecular mechanism underlying the effect of EGF on PNNs using fluorescent substrates for matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs). EGF increased the enzyme activity of MMPs and ADAMs in cultured neurons. These enzyme activities were also increased in the EGF-Tg mice cortex. GM6001, a broad inhibitor of MMPs and ADAMs, also blocked EGF-induced PNN reductions. Therefore, EGF/EGF receptor signals may regulate PNN formation in the developing cortex.

Hierarchically Assembled Nanofiber Scaffolds with Dual Growth Factor Gradients Promote Skin Wound Healing Through Rapid Cell Recruitment.

To address current challenges in effectively treating large skin defects caused by trauma in clinical medicine, the fabrication, and evaluation of a novel radially aligned nanofiber scaffold (RAS) with dual growth factor gradients is presented. These aligned nanofibers and the scaffold's spatial design provide many all-around "highways" for cell migration from the edge of the wound to the center area. Besides, the chemotaxis induced by two growth factor gradients further promotes cell migration. Incorporating epidermal growth factor (EGF) aids in the proliferation and differentiation of basal layer cells in the epidermis, augmenting the scaffold's ability to promote epidermal regeneration. Concurrently, the scaffold-bound vascular endothelial growth factor (VEGF) recruits vascular endothelial cells at the wound's center, resulting in angiogenesis and improving blood supply and nutrient delivery, which is critical for granulation tissue regeneration. The RAS+EGF+VEGF group demonstrates superior performance in wound immune regulation, wound closure, hair follicle regeneration, and ECM deposition and remodeling compared to other groups. This study highlights the promising potential of hierarchically assembled nanofiber scaffolds with dual growth factor gradients for wound repair and tissue regeneration applications.