Self-assembly of PEG-PPS polymers and LL-37 peptide nanomicelles improves the oxidative microenvironment and promotes angiogenesis to facilitate chronic wound healing.

Refractory diabetic wounds are associated with high incidence, mortality, and recurrence rates and are a devastating and rapidly growing clinical problem. However, treating these wounds is difficult owing to uncontrolled inflammatory microenvironments and defective angiogenesis in the affected areas, with no established effective treatment to the best of our knowledge. Herein, we optimized a dual functional therapeutic agent based on the assembly of LL-37 peptides and diblock copolymer poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS). The incorporation of PEG-PPS enabled responsive or controlled LL-37 peptide release in the presence of reactive oxygen species (ROS). LL-37@PEG-PPS nanomicelles not only scavenged excessive ROS to improve the microenvironment for angiogenesis but also released LL-37 peptides and protected them from degradation, thereby robustly increasing angiogenesis. Diabetic wounds treated with LL-37@PEG-PPS exhibited accelerated and high-quality wound healing in vivo. This study shows that LL-37@PEG-PPS can restore beneficial angiogenesis in the wound microenvironment by continuously providing angiogenesis-promoting signals. Thus, it may be a promising drug for improving chronic refractory wound healing.

Recent advances in peptide-based bioactive hydrogels for nerve repair and regeneration: from material design to fabrication, functional tailoring and applications.

The injury of both central and peripheral nervous systems can result in neurological disorders and severe nervous diseases, which has been one of the challenges in the medical field. The use of peptide-based hydrogels for nerve repair and regeneration (NRR) provides a promising way for treating these problems, but the effects of the functions of peptide hydrogels on the NRR efficiency have been not understood clearly. In this review, we present recent advances in the material design, matrix fabrication, functional tailoring, and NRR applications of three types of peptide-based hydrogels, including pure peptide hydrogels, other component-functionalized peptide hydrogels, and peptide-modified polymer hydrogels. The case studies on the utilization of various peptide-based hydrogels for NRR are introduced and analyzed, in which the effects and mechanisms of the functions of hydrogels on NRR are illustrated specifically. In addition, the fabrication of medical NRR scaffolds and devices for pre-clinical application is demonstrated. Finally, we provide potential directions on the development of this promising topic. This comprehensive review could be valuable for readers to know the design and synthesis strategies of bioactive peptide hydrogels, as well as their functional tailoring, in order to promote their practical applications in tissue engineering, biomedical engineering, and materials science.

Overexpression of SIRT6 regulates NRF2/HO-1 and NF-κB signaling pathways to alleviate UVA-induced photoaging in skin fibroblasts.

Skin photoaging, resulting from prolonged exposure to sunlight, especially UVA rays, has been identified as a key contributor to age-related skin degeneration. However, the mechanism by which UVA radiation induces skin cell senescence has not been fully elucidated. In this investigation, bioinformatics technology was employed to identify SIRT6 as the core hub gene involved in the progression of skin photoaging. The study evinced that prolonged exposure of cutaneous fibroblasts to UVA radiation results in a marked reduction in the expression of SIRT6, both in vivo and in vitro. Knockdown of SIRT6 in skin fibroblasts resulted in the upregulation of genes associated with cellular aging, thereby exacerbating the effects of UVA radiation-induced photoaging. Conversely, overexpression of SIRT6 decreased the expression of cell aging-related genes, indicating that SIRT6 plays a role in the regulation of senescence in skin fibroblasts induced by UVA radiation. We proffer substantiation that overexpression of SIRT6 protects skin fibroblasts from UVA-induced oxidative stress by activating the NRF2/HO-1 signaling cascade. Moreover, SIRT6 overexpression also reduced UVA-induced type I collagen degradation by inhibiting NF-κB signaling cascade. In summary, our findings showed that overexpression of SIRT6 inhibits UVA-induced senescence phenotype and type I collagen degradation in skin fibroblasts by modulating the NRF2/HO-1 and NF-κB signaling pathways. And the regulation of these signaling pathways by SIRT6 may be achieved through its deacetylase activity. Therefore, SIRT6 is a novel and promising therapeutic target for skin aging related to age and UV.

Recent advance in bioactive hydrogels for repairing spinal cord injury: material design, biofunctional regulation, and applications.

Functional hydrogels show potential application in repairing spinal cord injury (SCI) due to their unique chemical, physical, and biological properties and functions. In this comprehensive review, we present recent advance in the material design, functional regulation, and SCI repair applications of bioactive hydrogels. Different from previously released reviews on hydrogels and three-dimensional scaffolds for the SCI repair, this work focuses on the strategies for material design and biologically functional regulation of hydrogels, specifically aiming to show how these significant efforts can promoting the repairing performance of SCI. We demonstrate various methods and techniques for the fabrication of bioactive hydrogels with the biological components such as DNA, proteins, peptides, biomass polysaccharides, and biopolymers to obtain unique biological properties of hydrogels, including the cell biocompatibility, self-healing, anti-bacterial activity, injectability, bio-adhesion, bio-degradation, and other multi-functions for repairing SCI. The functional regulation of bioactive hydrogels with drugs/growth factors, polymers, nanoparticles, one-dimensional materials, and two-dimensional materials for highly effective treating SCI are introduced and discussed in detail. This work shows new viewpoints and ideas on the design and synthesis of bioactive hydrogels with the state-of-the-art knowledges of materials science and nanotechnology, and will bridge the connection of materials science and biomedicine, and further inspire clinical potential of bioactive hydrogels in biomedical fields.

Edaravone promotes viability of random skin flaps via activating PI3K/Akt/mTOR signalling pathway-mediated enhancement of autophagy.

Random skin flap transplantation is a commonly used technique. However, ischemia and ischemia-reperfusion injury always impair its therapeutic effectiveness through acclerating oxidative stress, apoptosis and suppressing angiogenesis. To survive, cells rely on mediating autophagy, DNA repair, immunoregulation to resist these cellular injuries. Thus, mediating autophagy may affect the survival of random skin flaps. The edaravone (EDA), a oxygen radicals scavenger, also possesses autophagy mediator potential, we investigated the effects of EDA on skin flap survival and its autophagy-related mechanisms. In vivo, mice were administered EDA or saline intraperitoneally for 7 days postoperatively. We found that EDA ameliorated the viability of random skin flaps, promoted autophagy and angiogenesis, attenuated apoptosis and oxidative stress. In vitro, mouse umbilical vascular endothelial cells (MUVECs) were administered EDA or 3-methyladenine (3-MA, an autophagy inhibitor) or rapacymin (Rapa, an autophagy activator) at the beginning of oxygen glucose deprivation (OGD). We found that EDA promoted cell viability, activated autophagy, enhanced angiogenesis, alleviated apoptosis and oxidative stress. On one hand, 3-MA reversed the effects of EDA on cell viability, oxidative stress and apoptosis via inhibiting autophagy. On the other hand, Rapa had the similar effects of EDA. Furthermore, EDA-induced autophagy was mediated through downregulating PI3K/Akt/mTOR signalling pathway. The findings showed that EDA ameliorated viability of random skin flaps by promoting angiogenesis, suppressing oxidative stress and apoptosis, which may be mediated by autophagic activation through downregulating PI3K/AKT/mTOR signalling pathway.

Autophagy promotes directed migration of HUVEC in response to electric fields through the ROS/SIRT1/FOXO1 pathway.

Endogenous electric fields (EFs) have been confirmed to facilitate angiogenesis through guiding directional migration of endothelial cells (ECs), but the underlying mechanisms remain obscure. Recent studies suggest that the directed migration of ECs in angiogenesis is correlated with autophagy, and the latter of which could be augmented by EFs. We hypothesize that autophagy may participate in the EFs-guided migration of ECs during angiogenesis. Herein, we showed that EFs induced human umbilical vein endothelial cells (HUVEC) migration toward the cathode with enhanced autophagy. Genetic ablation of autophagy by silencing the autophagy-related gene (Atg) 5 abolished the EFs-directed migration of HUVEC, indicating that autophagy is definitely required for EFs-guided migration of cells. Mechanistically, we identified the intracellular reactive oxygen species (ROS) as a crucial mediator in EFs-triggered autophagy through augmenting the silencing information regulator 2 related enzyme1 (SIRT1)/forkhead box protein O1 (FOXO1) signaling. Either ROS scavenging or SIRT1 knockdown eliminated the EFs-triggered autophagy in HUVEC. Further study showed that SIRT1 promoted FOXO1 deacetylation, facilitating its nuclear accumulation and transcriptional activity, and thereby activating autophagy in EFs-treated HUVECs. In conclusion, our study demonstrated a pivotal role for autophagy in EFs-induced directed migration of HUVECs through the ROS/SIRT1/FOXO1 pathway, and provided a novel theoretical foundation for angiogenesis.

Promoting Re-epithelialization in an oxidative diabetic wound microenvironment using self-assembly of a ROS-responsive polymer and P311 peptide micelles.

Engineering smart nano-therapeutics for re-epithelialisation of chronic wounds facilitates the wound healing process. However, due to excessive oxidative stress damage and persistent inflammation in diabetic wound microenvironment, the migration of stimulating epidermal cells in diabetic wounds represents a significant challenge. Here we synthesised P311-loaded micelles by self-assembly of P311 peptides and diblock copolymer poly (ethylene glycol)-block-poly (propylene sulfide) (PEG-b-PPS, denoted as PEPS) that have unique ability to transform an oxidative wound microenvironment into a proregenerative one while also providing cues for epidermal cell migration. The P311@PEPS showed an accelerated migration of epidermal cells via activation of the Akt signalling pathway, simultaneously suppressing the unfavourable oxidative wound microenvironment by scavenging reactive oxygen species (ROS), ultimately leading to the induction of an environment conducive to cell migration. Furthermore, the micelles were able to bypass the inhibitory effect of ROS on the Akt signalling pathway, thereby promoting epidermal cell migration. Additionally, we observed that diabetic wounds treated with P311@PEPS showed accelerated chronic wound healing, granulation tissue formation, collagen deposition and re-epithelialisation, thereby suggesting the efficacy of P311@PEPS as a promising nanoplatform for the treatment of chronic wounds. STATEMENT OF SIGNIFICANCE: Based on the unique conditions of the diabetic wound microenvironment, a smart drug delivery system with ROS-responsive nanomaterials has been widely investigated to enhance diabetic wound healing. In our previous studies, we observed that P311 promotes epidermal cell migration to induce wound re-epithelialisation. However, the application of P311 suffers from its instability. Herein, we developed a therapeutic platform with P311-loaded micelles (P311@PEPS), which were synthesized by the self-assembly of P311 peptides and diblock copolymer poly (ethylene glycol)-block-poly (propylene sulfide) (PEG-b-PPS, denoted as PEPS). These micelles provide continuous migration signals for epidermal cells by ROS-trigged P311 release. Additionally, P311@PEPS scavenges excess ROS and provides a microenvironment that reduces inflammation, which could protect P311 from enzymatic degradation and improve the bioavailability of P311.

Astragaloside IV attenuates high glucose-induced human keratinocytes injury via TGF-ß/Smad signaling pathway.

OBJECTIVES: In this study, we have investigated the effect of Astragaloside IV on keratinocytes' proliferation, migration, oxidative stress, apoptosis, inflammation, and relevant signaling pathway, using human keratinocytes exposed to high glucose. BACKGROUND: Astragaloside IV is one of the main active ingredients of Astragalus membranaceus (Fisch.) Bunge. Previous studies have found that Astragaloside IV exerts positive effects in various disease models and promotes wound healing. METHODS: Cell proliferation and migration of keratinocytes, oxidative stress indicators, cell apoptosis rate, inflammatory factors, and key proteins in the TGF-ß/Smad signaling pathway were evaluated by molecular biology/biochemical techniques, fluorescence microscope, and flow cytometry. RESULTS: High glucose inhibited the cell proliferation and migration of keratinocytes, upregulated the levels of MDA, ROS, IL-6, IL-8, and Smad7, and decreased the levels of SOD, IL-10, TGF-ß1, p-Smad2, and p-Smad3. Astragaloside IV attenuated the dysfunction of keratinocytes, oxidative stress, cell apoptosis, and inflammation, but activated TGF-ß/Smad signaling pathway. Meanwhile, the addition of SB431542 (the inhibitor of TGF-ß/Smad signaling pathway) eliminated the impact of Astragaloside IV on high glucose-induced keratinocytes. CONCLUSIONS: These results strongly suggest that Astragaloside IV may be a potential drug candidate for accelerating diabetic wound healing, by protecting keratinocytes against damages induced by high glucose and TGF-ß/Smad pathway is involved in this process at the cellular level.

Histatin-1 alleviates high-glucose injury to skin keratinocytes through MAPK signaling pathway.

BACKGROUND: Damage to keratinocytes and other skin cells in a high-glucose environment has been proven to be an important reason for the poor wound healing ability of chronic diabetes mellitus. Histatin-1 has been preliminarily proven to stimulate the wound healing process of the oral and non-oral mucosa and has been found to be related to the activation of extracellular signal-regulated kinase (ERK). AIM OF THE STUDY: The purpose of this study was to investigate the effect of histatin-1 on high-glucose-injured keratinocytes and the role of the Ras-Raf-MEK-ERK signaling pathway on the effect of histatin-1 to improve diabetic wound healing. METHODS: A human keratinocyte model damaged by high glucose was constructed, cell proliferation was detected by the Cell Counting Kit-8 assay, and cell apoptosis was detected by flow cytometry. The expression level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) was detected by ELISA, and the mitogen-activated protein kinase (MAPK) signaling pathway protein expression level was detected by Western blot. C-fos mRNA expression was detected by real-time PCR. RESULTS: The results indicated that histatin-1 promoted proliferation and reduced the rate of apoptosis and 8-OHdG content in keratinocytes with high-glucose injury. In addition, histatin-1 down-regulated MEK phosphorylation in keratinocytes with high-glucose injury. However, with the extension of the intervention, the effect of histatin-1 on c-fos mRNA expression was different. At the early stage of high-glucose injury (12 h), the expression of c-fos mRNA was not increased in high-glucose-injured keratinocytes treated with histatin-1 but then c-fos mRNA expression was gradually upregulated. CONCLUSION: Histatin-1 could alleviate keratinocyte injury caused by high glucose levels and promoted wound healing in vitro. In addition, histatin-1 could exert anti-apoptotic and antioxidant damage effects under high-glucose injury states. These effects of histatin-1 may be related to its regulation of the MAPK signaling pathway. Therefore, these findings provide an essential theoretical basis for histatin-1 to become a safe and effective new peptide biological agent to promote wound healing in patients with diabetes.

Therapeutic effects of ephrin B receptor 2 inhibitors screened by molecular docking on cutaneous squamous cell carcinoma.

BACKGROUND: Cutaneous squamous cell carcinoma (CSCC) is the most known form type of metastatic skin cancer. Activation of ephrin B receptor 2 (EphB2) signaling can promote the metastasis, invasion, and angiogenesis of CSCC cells. Therefore, EphB2 may act as a therapeutic target for CSCC. Here, we screened the inhibitors for EphB2 using molecular docking and then evaluated the effects of the identified inhibitors on cancer-related features of CSCC cells. METHODS: The Schrodinger docking tool was used to predict the three-dimensional structure of EphB2 protein and its ligand binding sites, and EphB2 inhibitors were screened by high-throughput virtual screening combined with molecular docking. The effects of EphB2 inhibitors were analyzed for cell viability, proliferation, apoptosis, migration, invasion, and xenograft tumor growth. RESULTS: In vitro experiments, the identified small-molecule inhibitors markedly inhibited the skin cancer cells proliferation, induced apoptosis, altered the cell cycle, and inhibited cell invasion and migration in our study. In a xenograft model, the identified small-molecule inhibitors induced changes in the epithelial mesenchymal transition, which affected the progression of CSCC. CONCLUSION: EphB2 small-molecule inhibitors had anti-CSCC effects, establishing a solid theoretical basis for clinical research.

Pilonidal sinus involving the breast in a man: A case report and literature review.

RATIONALE: Pilonidal sinus disease (PSD) involving the breast is extremely rare and has not been described in man. PATIENT CONCERNS: This current case report presents a case of a pilonidal cyst in a 46-year-old man which was surgically treated. He had intermittent pain in his left breast for 2 months and came for local rupture and discharge for 1 week. DIAGNOSIS: The initial diagnosis is male mastitis, on the basis of the histological features of H&E-stained specimens and immunohistochemistry of the resected lump, this case was diagnosed as PSD. INTERVENTIONS: The patient underwent "enlarged resection of the left breast lesion" under local anesthesia. OUTCOMES: The patient's surgical area healed well, without any signs of recurrence. CONCLUSION: PSD involving the breast is extremely rare in man, with no typically clinical manifestations, and could be easily ignored. This disease requires great attentions from clinicians.

Effects and mechanisms of histatins as novel skin wound-healing agents.

Wound healing is a complex and important physiological process that maintains the integrity of skin after various injuries. Abnormal wound healing, especially of chronic wounds, impairs normal physical function. Therefore, the search for effective and safe healing agents is one of the main concerns. Histatins are histidine-rich low molecular weight peptides that are expressed in the saliva of both humans and higher primates. Histatins have two main biological effects, cell stimulation and bacteria killing, with the former playing an important role in wound healing by promoting epithelial cell and fibroblast migration and angiogenesis and enhancing the re-epithelialization of the wounded area. Because of these biological effects, histatins have been shown to be promising agents of improved wound healing. Histatins are categorized into many subtypes, of which histatin 1 and its hydrolysates are the most effective in promoting wound healing. This review addresses the bioactivity of histatins in wound healing, such as their stimulatory effects on epithelial cells and fibroblasts, and elucidates the possible mechanisms by which histatin subtypes induce their biological effects.

The cardiovascular protective effect and mechanism of calycosin and its derivatives.

Cardiovascular disease is the main cause of mortality and morbidity in the world, especially in developing countries. Drug therapy is one of the main ways to treat cardiovascular diseases. Among them, great progress has been made in the treatment of cardiovascular diseases with traditional Chinese medicine. In terms of experimental research, the mechanism of traditional Chinese medicine in the treatment of cardiovascular diseases has been thoroughly discussed in vitro and in vivo. In terms of clinical treatment, traditional Chinese medicine with flavonoids, saponins and alkaloids as the main effective components has a definite effect on the treatment of cardiovascular diseases such as arrhythmia, myocardial ischemia, angina pectoris and myocardial infarction, with high safety and good application prospects. With the further research on the effective ingredients, mechanism and adverse reactions of traditional Chinese medicine, it will be beneficial to the effectiveness of traditional Chinese medicine, reduce side effects and promote the modernization of traditional Chinese medicine. Calycosin and its derivatives, the main bioactive flavonoids in Astragalus membranaceus have multiple biological effects, such as antioxidant, pro-angiogenesis, anti-tumour, and anti-inflammatory effects. Based on the above biological effects, calycosin has been shown to have good potential for cardiovascular protection. The potent antioxidant effect of calycosin may play an important role in the cardiovascular protective potential. For injured cardiac myocytes, calycosin and its derivatives can alleviate the cell damage mainly marked by the release of myocardial enzymes and reduce the death level of cardiac myocytes mainly characterized by apoptosis through various mechanisms. For vascular endothelial cells, calycosin also has multiple effects and multiple mechanisms, such as promoting vascular endothelial cell proliferation, exerting vasodilating effect and directly affecting the synthesis function of endothelial cells. The present review will address the bioactivity of calycosin in cardiovascular diseases such as protective effects on cardiac myocytes and vascular endothelial cells and elucidate main mechanism of calycosin and its derivatives to exert the above biological effects.

Analysis on outcomes of facial paralysis complicated by middle ear cholesteatoma.

BACKGROUND: The prognostic factors of facial paralysis complicated by middle ear cholesteatoma (MEC) are largely unknown due to limited reports and smaller sample size. OBJECTIVES: This study aimed to analyze prognostic factors of postoperative outcomes of facial paralysis complicated by MEC. MATERIAL AND METHODS: Clinical data of 48 patients (48 ears) with facial paralysis complicated by MEC were retrospectively reviewed and analyzed. The outcomes of facial paralysis were compared between different groups. RESULTS: All the eight cases (100%) with intact fallopian canal had complete recovery of facial paralysis after surgery, while only 52.5% cases (21/40 cases) with fallopian canal damage achieved good recovery, with significant difference (p < .05). For subgroup analysis of the 40 cases with damaged fallopian canal, the good recovery rate of facial paralysis in shorter duration group (≤2 months) was higher compared to longer duration group (>2 months) (81.0% versus 21.1%; p < .05). Moreover, the good recovery rate of facial paralysis in moderate facial paralysis group (grade II-IV) was higher compared to severe facial paralysis group (grade V-VI) (82.4% versus 30.4%; p < .05). CONCLUSIONS AND SIGNIFICANCE: The outcomes of facial paralysis complicated by MEC were associated with fallopian canal integrity, duration and severity of facial paralysis.