Melatonin protects endothelial progenitor cells against AGE-induced apoptosis via autophagy flux stimulation and promotes wound healing in diabetic mice

P75NTR regulates autophagy through the YAP-mTOR pathway to increase the proliferation of interfollicular epidermal cells and promote wound healing in diabetic mice

Wound healing is delayed in diabetic patients. Increased autophagy and dysfunction of interfollicular epidermal (IFE) cells are closely associated with delayed healing of diabetic wounds. Autophagy plays an important role in all stages of wound healing, but its role in diabetic wound healing and the underlying molecular mechanisms are not clear. Here, we found that diabetic mice had delayed wound healing and increased autophagy in wounds compared with normal mice and that chloroquine, an inhibitor of autophagy, decreased the level of autophagy, improved the function of IFE cells, and accelerated wound healing in diabetic mice. Treatment of IFE cells with advanced glycosylation end products (AGEs) resulted in increased microtubule-associated protein chain (LC3) expression and decreased prostacyclin-62 (P62) expression, indicating increased autophagy in AGE-treated IFE cells. Moreover, P75NTR reduced autophagy in IFE cells in the presence of AGEs and significantly increased the proliferation of IFE cells. In addition, P75NTR participated in regulating autophagy in IFE cells and in wounds in diabetic mice through the YAP-mTOR signalling pathway, which increased the functional activity of the cells and the healing rate of wounds in diabetic mice. Thus, our study suggests that P75NTR protects IFE cells against AGEs by affecting autophagy and accelerating wound healing in diabetic mice, providing a basis for understanding the role of autophagy in diabetic wound healing.

Polyvinylpyrrolidone/chitosan-loaded dihydromyricetin-based nanofiber membrane promotes diabetic wound healing by anti-inflammatory and regulating autophagy-associated protein expression

The healing of wounds in diabetics is commonly delayed by recurring infections and persistent inflammation at the wound site. For this reason, we conducted a study using the electrospinning technique to create nanofiber membranes consisting of polyvinylpyrrolidone/chitosan (PVP/CS) and incorporated dihydromyricetin (DHM) into them. Infrared Fourier transform spectroscopy and scanning electron microscopy were used to analyze the nanofiber membrane. Experimental results in vitro have shown that PVP/CS/DHM has exceptional properties such as hydrophilicity, porosity, water vapor transport rate, antioxidant capacity, and antibacterial activity. Moreover, our study has demonstrated that the application of PVP/CS/DHM can significantly improve wound healing in diabetic mice. After an 18-day treatment period, a remarkable wound closure rate of 88.63 ± 1.37 % was achieved. The in vivo experiments revealed that PVP/CS/DHM can promote diabetic wound healing by suppressing the activation of TLR4/MyD88/NF-κB signaling pathway and enhancing autophagy-related protein as well as CD31 and HIF-1α expression in skin tissues. This study showed that PVP/CS/DHM is a promising wound dressing.

Harnessing cytokine-induced killer cells to accelerate diabetic wound healing: an approach to regulating post-traumatic inflammation

Impaired immunohomeostasis in diabetic wounds prolongs inflammation and cytokine dysfunction, thus, delaying or preventing wound-surface healing. Extensive clinical studies have been conducted on cytokine-induced killer (CIK) cells recently, as they can be easily proliferated using a straightforward, inexpensive protocol. Therefore, the function of CIK cells in regulating inflammatory environments has been drawing attention for clinical management. Throughout the current investigation, we discovered the regenerative capacity of these cells in the challenging environment of wounds that heal poorly due to diabetes. We demonstrated that the intravenous injection of CIK cells can re-establish a proregenerative inflammatory microenvironment, promote vascularization and, ultimately, accelerate skin healing in diabetic mice. The results indicated that CIK cell treatment affects macrophage polarization and restores the function of regenerative cells under hyperglycemic conditions. This novel cellular therapy offers a promising intervention for clinical applications through specific inflammatory regulation functions.

Evaluating the effectiveness of melatonin in reducing the risk of foot ulcers in diabetic patients

Objectives

Diabetes and its complications, as a major health concern, are associated with morbidity and mortality around the world. One of these complications is diabetic foot ulcer. Factors such as hyperglycemia, neuropathy, vascular damage and impaired immune system can cause foot ulcers. The present review aims to study the potential effects of melatonin, the main product of pineal glands, on diabetic foot ulcers.

Methods

A narrative review was performed using present literature in an attempt to identify the different aspects of melatonin's impact on diabetic foot ulcers by searching related keywords in electronic databases without any restriction.

Results

This review shows that, melatonin has anti-diabetic effects. It is effective in reducing the risk of hyperglycemia, neuropathy, vascular damage and immune system impairment in diabetic patients. By reducing these complications with melatonin, correspondingly, the incidence of diabetic foot ulcers may also decrease in these patients.

Conclusions

The results of this study indicate promising properties of melatonin while dealing with diabetic foot ulcers and their common underlying conditions, but still, it needs to be investigated more in future studies.

Sericin and melatonin mitigate diethylnitrosamine-instigated testicular impairment in mice: Implications of oxidative stress, spermatogenesis, steroidogenesis, and modulation of Nrf2/WT1/SF-1 signaling pathways

AIMS

This study aimed to investigate the therapeutic influence of combination therapy with sericin and melatonin on attenuating diethylnitrosamine (DEN)-instigated testicular dysfunction in mice and defining the molecular mechanisms involved in orchestrating redox signaling pathways and restoring spermatogenesis and steroidogenesis.

MATERIALS AND METHODS

Different groups of male Swiss albino mice were established and injected with respective drugs intraperitoneally. Semen analysis, hormonal assays, and oxidative stress biomarkers were evaluated. Additionally, melatonin and its receptors, WT1, SF-1, vimentin, Nrf2, and ANXA1 expressions were assessed. Histopathological and ultrastructural features of the testes were investigated by semithin, SEM, and TEM analyses.

KEY FINDINGS

Exposure to DEN exhibited pathophysiological consequences, including a remarkable increase in lipid peroxidation associated with substantial diminutions in SOD, CAT, GPx, GSH, GSH:GSSG, and GST. Furthermore, it disrupted spermatozoa integrity, testosterone, FSH, LH, melatonin, and its receptors (MT1 and MT2) levels, implying spermatogenesis dysfunction. By contrast, treatment with sericin and melatonin significantly restored these disturbances. Interestingly, the combination therapy of sericin and melatonin noticeably augmented the Nrf2, WT1, and SF-1 expressions compared to DEN-treated mice, deciphering the amelioration perceived in antioxidant defense and spermatogenesis inside cells. Furthermore, immunohistochemical detection of ANXA1 alongside histopathological and ultrastructural analyses revealed evident maintenance of testicular structures without discernible inflammation or anomalies in mice administered with sericin and melatonin compared to the DEN-treated group.

SIGNIFICANCE

Our findings highlighted that treatment with sericin and melatonin alleviated the testicular tissues in mice from oxidative stress and dysregulated spermatogenesis and steroidogenesis engendered by DEN.

Fiber-reinforced gelatin/β-cyclodextrin hydrogels loaded with platelet-rich plasma-derived exosomes for diabetic wound healing

Diabetic complications with high-glucose status (HGS) cause the dysregulated autophagy and excessive apoptosis of multiple-type cells, leading to the difficulty in wound self-healing. Herein, we firstly developed fiber-reinforced gelatin (GEL)/β-cyclodextrin (β-CD) therapeutic hydrogels by the modification of platelet-rich plasma exosomes (PRP-EXOs). The GEL fibers that were uniformly dispersed within the GEL/β-CD hydrogels remarkably enhanced the compression strengths and viscoelasticity. The PRP-EXOs were encapsulated in the hydrogels via the covalent crosslinking between the PRP-EXOs and genipin. The diabetic rat models demonstrated that the GEL/β-CD hydrogels and PRP-EXOs cooperatively promoted diabetic wound healing. On the one hand, the GEL/β-CD hydrogels provided the biocompatible microenvironments and active components for cell adhesion, proliferation and skin tissue regeneration. On the other hand, the PRP-EXOs in the therapeutic hydrogels significantly activated the autophagy and inhibited the apoptosis of human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts (HSFs). The activation of autophagy and inhibition of apoptosis in HUVECs and HSFs induced the blood vessel creation, collagen formation and re-epithelialization. Taken together, this work proved that the incorporation of PRP-EXOs in a wound dressing was an effective strategy to regulate autophagy and apoptosis, and provide a novel therapeutic platform for diabetic wound healing.

Deciphering The Emerging Role of Programmed Cell Death in Diabetic Wound Healing

Diabetic wounds are characterized by delayed and incomplete healing. As one of the most common complications of diabetes, diabetic wounds can be fatal in some cases. Programmed cell death (PCD) is an active and ordered cell death mode determined by genes, including apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis. It is currently believed that PCD plays a crucial role in diabetic wound healing. Diabetic hyperglycemic environments can lead to abnormal PCD in various cells during healing processes, thereby affecting the activity and function of cells and interfering with diabetic wound healing. Therefore, this review focuses on the new roles and mechanisms of PCD in diabetic wound healing. Moreover, the challenges and perspectives related to PCD in diabetic wound healing are presented, which will bring new insights to improve diabetic wound healing.

Procyanidin B2: A promising multi-functional food-derived pigment for human diseases

Natural edible pigments play a paramount part in the food industry. Procyanidin B2 (PB2), one of the most representative naturally occurring edible pigments, is usually isolated from the seeds, fruits, and leaves of lots of common plants, such as grapes, Hawthorn, black soybean, as well as blueberry, and functions as a food additive in daily life. Notably, PB2 has numerous bioactivities and possesses the potential to treat/prevent a wide range of human diseases, such as diabetes mellitus, diabetic complications, atherosclerosis, and non-alcoholic fatty liver disease, and the underlying mechanisms were partially elucidated, including mediating signaling pathways like NF-κB, MAPK, PI3K/Akt, apoptotic axis, and Nrf-2/HO-1. This paper presents a review of the natural sources, bioactivities, and the therapeutic/preventive potential of PB2 and the possible mechanisms, with the aim of promoting the development of PB2 as a functional food and providing references for its clinical application in the treatment of diseases.

The Effect of Melatonin on Nasal Septal Wound Healing in an Experimental Animal Model

The purpose of our study was to examine the effect of melatonin (MLT) on wound healing in the nasal septum. Twenty-two Sprague-Dawley rats of the male sex were included in this experimental study. Nasal septal perforation (NSP), about 2 mm in diameter, was formed in each rat. MLT was applied topically to the subjects in the study group and saline was applied topically to the subjects in the control group once a day for 14 days. On day 14, the rats were sacrificed and the nasal septums of the subjects were resected for pathological evaluation. In the NSP area, degeneration and regeneration of nasal septal epithelium; degeneration and regeneration of the septal cartilage; number of cells involved in wound healing such as acute inflammatory cells (leukocytes), fibroblast, eosinophil, and giant cell; capillary vessel intensity; granulation tissue formation; and collagen intensity parameters were evaluated histopathologically. The macroscopic size and histopathologic examination results of NSPs were statistically analyzed. In the MLT group, the epithelium regeneration, cartilage regeneration, fibroblast number, collagen density, vascularity, and granulation formation were significantly higher, and the epithelial degeneration and acute inflammatory cells density were significantly lower, in the NSP area (p < 0.05). In addition, macroscopic healing was significantly higher in the MLT group (p = 0.044 and <0.05). Local application of MLT accelerates nasal septal wound healing. With this feature, the usage of MLT can be promising to prevent the formation of NSP.

The role of autophagy in bone metabolism and clinical significance

The skeletal system is the basis of the vertebral body composition, which affords stabilization sites for muscle attachment, protects vital organs, stores mineral ions, supplies places to the hematopoietic system, and participates in complex endocrine and immune system. Not surprisingly, bones are constantly reabsorbed, formed, and remodeled under physiological conditions. Once bone metabolic homeostasis is interrupted (including inflammation, tumors, fractures, and bone metabolic diseases), the body rapidly initiates bone regeneration to maintain bone tissue structure and quality. Macroautophagy/autophagy is an essential metabolic process in eukaryotic cells, which maintains metabolic energy homeostasis and plays a vital role in bone regeneration by controlling molecular degradation and organelle renewal. One relatively new observation is that mesenchymal cells, osteoblasts, osteoclasts, osteocytes, chondrocytes, and vascularization process exhibit autophagy, and the molecular mechanisms and targets involved are being explored and updated. The role of autophagy is also emerging in degenerative diseases (intervertebral disc degeneration [IVDD], osteoarthritis [OA], etc.) and bone metabolic diseases (osteoporosis [OP], osteitis deformans, osteosclerosis). The use of autophagy regulators to modulate autophagy has benefited bone regeneration, including MTOR (mechanistic target of rapamycin kinase) inhibitors, AMPK activators, and emerging phytochemicals. The application of biomaterials (especially nanomaterials) to trigger autophagy is also an attractive research direction, which can exert superior therapeutic properties from the material-loaded molecules/drugs or the material's properties such as shape, roughness, surface chemistry, etc. All of these have essential clinical significance with the discovery of autophagy associated signals, pathways, mechanisms, and treatments in bone diseases in the future.Abbreviations: Δψm: mitochondrial transmembrane potential AMPK: AMP-activated protein kinase ARO: autosomal recessive osteosclerosis ATF4: activating transcription factor 4 ATG: autophagy-related β-ECD: β-ecdysone BMSC: bone marrow mesenchymal stem cell ER: endoplasmic reticulum FOXO: forkhead box O GC: glucocorticoid HIF1A/HIF-1α: hypoxia inducible factor 1 subunit alpha HSC: hematopoietic stem cell HSP: heat shock protein IGF1: insulin like growth factor 1 IL1B/IL-1β: interleukin 1 beta IVDD: intervertebral disc degradation LPS: lipopolysaccharide MAPK: mitogen-activated protein kinase MSC: mesenchymal stem cell MTOR: mechanistic target of rapamycin kinase NP: nucleus pulposus NPWT: negative pressure wound therapy OA: osteoarthritis OP: osteoporosis PTH: parathyroid hormone ROS: reactive oxygen species SIRT1: sirtuin 1 SIRT3: sirtuin 3 SQSTM1/p62: sequestosome 1 TNFRSF11B/OPG: TNF receptor superfamily member 11b TNFRSF11A/RANK: tumor necrosis factor receptor superfamily, member 11a TNFSF11/RANKL: tumor necrosis factor (ligand) superfamily, member 11 TSC1: tuberous sclerosis complex 1 ULK1: unc-51 like autophagy activating kinase 1.

Platelet-rich Plasma (PRP) in the Treatment of Diabetic Foot Ulcers and its Regulation of Autophagy

Objective: Through clinical trials, this study observes the therapeutic effect of platelet-rich plasma (platelet-rich plasma, PRP) on diabetic foot ulcers and explored the relationship between the relationship between PRP and autophagy. Methods: Thirty patients with diabetic foot ulcer who met the relevant criteria were randomly divided into PRP treatment group and control group. In the PRP treatment group, the formed PRP gel was coated and bandaged on the diabetic foot ulcer wound, and the PRP treatment was repeated on the seventh day. The control group was covered with normal saline sterile gauze. Observe the healing rate of the wound in 7 days, 14 days and 21 days, the pain in 5 consecutive days and the healing time of the wound after treatment, collect wound granulation tissues before and twenty-first days after treatment then detect the expression of autophagy-related proteins (LC-3, P62) and inflammatory factors (IL-6, IL-10) in diabetic foot ulcer wound to investigate the potential relationship between PRP treatment of diabetic foot ulcers and autophagy and inflammatory responses. Results: The wound healing rate of diabetic foot ulcer patients in the PRP treatment group was higher than that in the control group on the seventh, 14th and 21st days, the healing time (31.40 ± 4.47) was better than that in the control group (43.20 ± 5.03) days, and the pain improvement was better than that in the control group (P < .05). The results of Western blot analysis and quantitative PCR of autophagy-related proteins (LC-3 and p62) in granulation tissue showed that the values of LC3 and LC3-II/LC3-I and the expression of LC3 gene in wound granulation tissue of PRP group were significantly higher than those before treatment (P < .05). The value and gene expression of P62 protein were lower than those before treatment (P < .05). In the control group, there was no significant difference in LC3 and P62 protein gray level and gene expression before and after treatment (P > .05). The level of autophagy in the wound of PRP group increased after treatment, while there was no statistical significance in the control group. The results of ELISA showed that the concentration of IL-6 in granulation tissue of the PRP treatment group was lower than that before treatment (P < .05), while there was no significant difference in IL-6 in the control group after treatment. The concentration of IL-10 increased in both groups after treatment, but the concentration in PRP group was higher than that in control group (P < .05). Conclusions: This study shows that PRP gel has advantages in accelerating wound healing, relieving pain, shortening healing time and reducing inflammatory response in treating diabetic foot ulcers wound, which may be related to autophagy, and provides new ideas for the treatment of diabetic foot ulcers.

Autophagy-Modulated Biomaterial: A Robust Weapon for Modulating the Wound Environment to Promote Skin Wound Healing

Autophagy, a self-renewal mechanism, can help to maintain the stability of the intracellular environment of organisms. Autophagy can also regulate several cellular functions and is strongly related to the onset and progression of several diseases. Wound healing is a biological process that is coregulated by different types of cells. However, it is troublesome owing to prolonged treatment duration and poor recovery. In recent years, biomaterials have been reported to influence the skin wound healing process by finely regulating autophagy. Biomaterials that regulate autophagy in various cells involved in skin wound healing to regulate the differentiation, proliferation and migration of cells, inflammatory responses, oxidative stress and formation of the extracellular matrix (ECM) have emerged as a key method for improving the tissue regeneration ability of biomaterials. During the inflammatory phase, autophagy enhances the clearance of pathogens from the wound site and leads to macrophage polarization from the M1 to the M2 phenotype, thus preventing enhanced inflammation that can lead to further tissue damage. Autophagy plays important roles in facilitating the formation of extracellular matrix (ECM) during the proliferative phase, removing excess intracellular ROS, and promoting the proliferation and differentiation of endothelial cells, fibroblasts, and keratinocytes. This review summarizes the close association between autophagy and skin wound healing and discusses the role of biomaterial-based autophagy in tissue regeneration. The applications of recent biomaterials designed to target autophagy are highlighted, including polymeric materials, cellular materials, metal nanomaterials, and carbon-based materials. A better understanding of biomaterial-regulated autophagy and skin regeneration and the underlying molecular mechanisms may open new possibilities for promoting skin regeneration. Moreover, this can lay the foundation for the development of more effective therapeutic approaches and novel biomaterials for clinical applications.

Melatonin pretreatment on exosomes: Heterogeneity, therapeutic effects, and usage

The therapeutic outcomes of exosome-based therapies have greatly exceeded initial expectations in many clinically intractable diseases due to the safety, low toxicity, and immunogenicity of exosomes, but the production of the exosomes is a bottleneck for wide use. To increase the yield of the exosomes, various solutions have been tried, such as hypoxia, extracellular acidic pH, etc. With a limited number of cells or exosomes, an alternative approach has been developed to improve the efficacy of exosomes through cell pretreatment recently. Melatonin is synthesized from tryptophan and secreted in the pineal gland, presenting a protective effect in pathological conditions. As a new pretreatment method, melatonin can effectively enhance the antioxidant, anti-inflammatory, and anti-apoptotic function of exosomes in chronic kidney disease, diabetic wound healing, and ischemia-reperfusion treatments. However, the current use of melatonin pretreatment varies widely. Here, we discuss the effects of melatonin pretreatment on the heterogeneity of exosomes based on the role of melatonin and further speculate on the possible mechanisms. Finally, the therapeutic use of exosomes and the usage of melatonin pretreatment are described.

Melatonin Improves Ischemia-Induced Circulation Recovery Impairment in Mice with Streptozotocin-Induced Diabetes by Improving the Endothelial Progenitor Cells Functioning

Patients with diabetes mellitus tend to develop ischemia-related complications and have compromised endothelial progenitor cell (EPC) function. Melatonin protects against ischemic injury, possibly via EPC modulation. We investigated whether melatonin pretreatment could restore EPC function impairment and improve circulation recovery in a diabetic critical limb ischemia mouse model. Under 25 mM high-glucose medium in vitro, EPC proliferation, nitric oxide production, tube formation, and endothelial nitric oxide synthase (eNOS) phosphorylation were significantly suppressed. Hyperglycemia promoted EPC senescence and apoptosis as well as increased reactive oxygen species (ROS) production. Melatonin treatment reversed the harmful effects of hyperglycemia on EPC through adenosine monophosphate–activated protein kinase-related mechanisms to increase eNOS phosphorylation and heme oxygenase-1 expression. In an in-vivo study, after a 4-week surgical induction of hindlimb ischemia, mice with streptozotocin (STZ)-induced diabetes showed significant reductions in new vessel formation, tissue reperfusion, and EPC mobilization in ischemic hindlimbs compared to non-diabetic mice. Mice with STZ-induced diabetes that received melatonin treatment (10 mg/kg/day, intraperitoneal) had significantly improved blood perfusion ratios of ischemic to non-ischemic limb, EPC mobilization, and densities of capillaries. In addition, a murine bone marrow transplantation model to support these findings demonstrated that melatonin stimulated bone marrow-originated EPCs to differentiate into vascular endothelial cells in femoral ligation-induced ischemic muscles. In summary, this study suggests that melatonin treatment augments EPC function along with neovascularization in response to ischemia in diabetic mice. We illustrated the protective effects of melatonin on EPC H2O2 production, senescence, and migration through melatonin receptors and modulating eNOS, AMPK, and HO-1 activities at the cellular level. Thus, melatonin might be used to treat the impairment of EPC mobilization and circulation recuperation in response to ischemic injury caused by chronic hyperglycemia. Additional studies are needed to elucidate the applicability of the results in humans.

SF/PVP nanofiber wound dressings loaded with phlorizin: preparation, characterization, in vivo and in vitro evaluation

Electrospinning-based wound dressings have multiple functions such as antibacterial, anti-inflammatory, and therapeutic, and are important in skin wound care. Herein, we designed a phlorizin (PHL)-loaded silk protein/polyvinylpyrrolidone (SF/PVP) composite nanofibrous membrane, which can be used as multiple wound dressings. In particular, SF/PVP/PHL scaffolds have high porosity and mechanical properties, exhibiting suitable permeability and hydrophilicity. The SF/PVP/PHL scaffolds containing PHL also have excellent antibacterial and antioxidant activities. Furthermore, the nanofiber significantly accelerated the wound healing process in a full-thickness skin injury model by enhancing wound re-epithelialization and collagen deposition density, increasing the content of macrophage antigen (CD68), platelet-endothelial cell adhesion molecule (CD31), proliferating cell nuclear antigen (PCNA) and inhibiting the expression of α-smooth muscle actin (α-SMA) at the wound site. The mechanism may be related to the inhibition of activation of phosphatidylinositol 3-kinase/serine-threonine kinase/ target of rapamycin (PI3K/AKT/mTOR) signaling pathway to enhance autophagy. Therefore, SF/PVP/PHL nanofibers can ideally meet the various requirements of the wound healing process and are promising wound dressing candidates for future clinical applications.

Antioxidant-enriched autologous biogel promoted diabetic wound healing by remodeling inherent posttraumatic inflammatory patterning and restoring compromised microenvironment homeostasis

Successful wound healing depends on the reconstruction of proper tissue homeostasis, particularly in the posttraumatic inflammatory tissue microenvironment. Diabetes jeopardizes tissues’ immune homeostasis in cutaneous wounds, causing persistent chronic inflammation and cytokine dysfunction. Previously, we developed an autologous regeneration factor (ARF) technology to extract the cytokine composite from autologous tissue to restore immune homeostasis and promote wound healing. However, treatment efficacy was significantly compromised in diabetic conditions. Therefore, we proposed that a combination of melatonin and ARF, which is beneficial for proper immune homeostasis reconstruction, could be an effective treatment for diabetic wounds. Our research showed that the utilization of melatonin-mediated ARF biogel (AM gel) promoted diabetic wound regeneration at a more rapid healing rate. RNA-seq analysis showed that AM gel treatment could restore more favorable immune tissue homeostasis with unique inflammatory patterning as a result of the diminished intensity of acute and chronic inflammation. Currently, AM gel could be a novel and promising therapeutic strategy for diabetic wounds in clinical practice through favorable immune homeostatic reconstructions in the tissue microenvironment and proper posttraumatic inflammation patterning.

Autophagy and skin wound healing

Autophagy is a lysosome-dependent, self-renewal mechanism that can degrade and recycle cellular components in eukaryotic cells to maintain the stability of the intracellular environment and the cells ability to cope with unfavorable environments. Numerous studies suggest that autophagy participates in regulating various cellular functions and is closely associated with the onset and progression of various diseases. Wound healing is a complex, multistep biological process that involves multiple cell types. Refractory wounds, which include diabetic skin ulcers, can seriously endanger human health. Previous studies have confirmed that autophagy plays an essential role in various phases of wound healing. Specifically, in the inflammatory phase, autophagy has an anti-infection effect and it negatively regulates the inflammatory response, which prevents excessive inflammation from causing tissue damage. In the proliferative phase, local hypoxia in the wound can induce autophagy, which plays a role in anti-apoptosis and anti-oxidative stress and promotes cell survival. Autophagy of vascular endothelial cells promotes wound angiogenesis and that of keratinocytes promotes their differentiation, proliferation and migration, which is conducive to the completion of wound re-epithelialisation. In the remodeling phase, autophagy of fibroblasts affects the formation of hypertrophic scars. Additionally, a refractory diabetic wound may be associated with increased levels of autophagy, and the regulation of mesenchymal stem cell autophagy may improve its application to wound healing. Therefore, understanding the relationship between autophagy and skin wound healing and exploring the molecular mechanism of autophagy regulation may provide novel strategies for the clinical treatment of wound healing.

New insights into the role of melatonin in diabetic cardiomyopathy

Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.

Regulation of endothelial progenitor cell functions during hyperglycemia: new therapeutic targets in diabetic wound healing

Diabetes is primarily characterized by hyperglycemia, and its high incidence is often very costly to patients, their families, and national economies. Unsurprisingly, the number and function of endothelial progenitor cells (EPCs) decrease in patients resulting in diabetic wound non-healing. As precursors of endothelial cells (ECs), these cells were discovered in 1997 and found to play an essential role in wound healing. Their function, number, and role in wound healing has been widely investigated. Hitherto, a lot of complex molecular mechanisms have been discovered. In this review, we summarize the mechanisms of how hyperglycemia affects the function and number of EPCs and how the affected cells impact wound healing. We aim to provide a complete summary of the relationship between diabetic hyperglycosemia, EPCs, and wound healing, as well as a better comprehensive platform for subsequent related research.

The progress and challenges of circRNA for diabetic foot ulcers: A mini-review

Since the Human Genome Project was successfully completed, humanity has entered a post-genome era, and the second-generation sequencing technology has gradually progressed and become more accurate. Meanwhile, circRNAs plays a crucial role in the regulation of diseases and potential clinical applications has gradually attracted the attention of physicians. However, the mechanisms of circRNAs regulation at the cellular and molecular level of diabetic foot ulcer (DFU) is still not well-understood. With the deepening of research, there have been many recent studies conducted to explore the effect of circRNAs on DFU. In this mini-review, we discuss the potential role of circRNAs as therapeutic targets and diagnostic markers for DFU in order to gain a better understanding of the molecular mechanisms that underlie the development of DFU and to establish a theoretical basis for accurate treatment and effective prevention.

Melatonin pre-treated bone marrow derived-mesenchymal stem cells prompt wound healing in rat models

Bone marrow derived-mesenchymal stem cells (BMSCs)-based therapy is an outstanding candidate for cutaneous wound healing. Melatonin (MEL) has been reported for its anti-inflammatory as well as tissue regenerative properties. Existing work aimed to explore the potential healing power of BMSCs pre-treated with MEL in a skin wound model. Adult rats were allocated into control, PIO, BMSCs (1 × 10⁵ cells), and MEL/BMSCs groups. On the 21 days post-wounding, tissues were sampled for analysis. The results demonstrated that compared to the control group, MEL/BMSCs therapy induced noticeable decline in wound area and elevated rate of wound retraction. Furthermore, marked increases in tissue hydroxyproline, as well as tissue content and gene expression level of vascular endothelial growth factor in MEL/BMSCs treated-wounded animals. Compared to the untreated control group, marked increases were found in antioxidant enzymatic activities together with elevated GSH levels in wounded tissues after MEL/BMSCs treatment. Moreover, therapeutically handled wounds with MEL/BMSCs revealed low levels of MDA, NO and protein carbonyls. Combined therapy with MEL/BMSCs relieved the inflammation witnessed by decreasing IL-1β, TNF-α and NF-κB levels in wounded tissues. Furthermore, noteworthy rises in levels of TGF-β and gene expression of α-SMA were noticed after MEL/BMSCs application that reveals their anti-scarring properties. Histologically, noticeable improvement in histopathological skin lesions in wound area and elevated the collagen synthesis and deposition. Collectively, the obtained data depict that the pre-treatment of BMSCs with MEL could potentially be a successful strategy for scaling-up the wound healing outcomes more than using BMSCs monotherapy in rat models.

Cyclosporin A alleviates trophoblast apoptosis and senescence by promoting autophagy in preeclampsia

INTRODUCTION

Abnormal extravillous trophoblast (EVT) function is closely related to preeclampsia (PE) and may be caused by inadequate autophagy, apoptosis, and senescence. Cyclosporin A (CsA) is an effective immunosuppressant that has been reported to stimulate autophagy and exert benign biological effects on EVTs. Therefore, we hypothesized that CsA may display therapeutic efficacy against PE by activating autophagy.

METHODS

We established the nitro-l-arginine methyl ester (l-NAME)-induced preeclamptic mice model and a hypoxia-reoxygenation (H/R) model in vitro. The effects of CsA on autophagy were evaluated by western blotting (WB). The effects of CsA on apoptosis were analyzed by Hematoxylin-eosin (H&E) staining, cell apoptosis assay and WB. Senescence-associated β-galactosidase (SA-β-gal) staining, RT-qPCR and WB were used to examine the senescence level. RT-qPCR were used to detect the senescence-associated secretory phenotype (SASP) level. DCFH-DA fluorescent probe, dihydroethidium (DHE) staining and mitochondrial membrane potential (ΔΨm) were used to detect senescence-associated mitochondrial dysfunction (SAMD).

RESULTS

CsA alleviated PE-like symptoms and reduced placental necrosis and senescence in mice injected with l-NAME. CsA ameliorated placental SASP and SAMD level induced by l-NAME. CsA also upregulated the expression of autophagic proteins in mouse placentas disrupted using l-NAME. In vitro, we found that CsA reversed H/R-induced apoptosis and senescence, as well as decreasing SASP and SAMD levels and upregulating autophagic proteins levels. Notably, 3-methyladenine (3-MA), an early phase inhibitor of autophagosome formation, abolished the protective effects of CsA against H/R.

DISCUSSION

CsA may display some therapeutic effects against PE by activating autophagy in vivo and in vitro.

Selenoprotein S attenuates high glucose and/or ox-LDL-induced endothelium injury by regulating Akt/mTOR signaling and autophagy

Glucolipid metabolism disorder in diabetes mellitus (DM) causes human endothelial injury and autophagy dysfunction is an important cause of endothelial dysfunction (ED). Selenoprotein S (SelS) could protect endothelium from oxidative stress, inflammatory responses, and apoptosis. This study assessed the effect of SelS on autophagy in glucolipid metabolic disorders and protection of the resulted vascular endothelial injury. The results showed that high glucose (HG), high oxidized low-density lipoprotein (HL), and HG combined with HL (HGL) could reduce viability of human aortic endothelial cells (HAECs), induce HAECs injury and increase SelS expression in a time-dependent manner. HG, HL, and HGL also initially induced autophagy but later reduced it in HAECs, while activity of the Akt/mTOR signaling was inhibited, especially in HGL culture of HAECs. SelS overexpression reduced the endothelial injury and autophagy and activated the Akt/mTOR signaling in HG, HL and HGL-cultured HAECs, compared to the control. Conversely, knockdown of SelS expression had the opposite effects on HAECs. In conclusion, SelS demonstrated a protective effect on endothelial injury induced by high glucose and/or ox-LDL and the underlying molecular events might be related to its regulation of HAECs autophagy by activating the Akt/mTOR signaling. SelS could be a potential intervention target in prevention and treatment of diabetic vascular complications.

Inhibition of the SEC61 translocon by mycolactone induces a protective autophagic response controlled by EIF2S1-dependent translation that does not require ULK1 activity

The Mycobacterium ulcerans exotoxin, mycolactone, is responsible for the immunosuppression and tissue necrosis that characterizes Buruli ulcer. Mycolactone inhibits SEC61-dependent co-translational translocation of proteins into the endoplasmic reticulum and the resultant cytosolic translation triggers degradation of mislocalized proteins by the ubiquitin-proteasome system. Inhibition of SEC61 by mycolactone also activates multiple EIF2S1/eIF2α kinases in the integrated stress response (ISR). Here we show mycolactone increased canonical markers of selective macroautophagy/autophagy LC3B-II, ubiquitin and SQSTM1/p62 in diverse disease-relevant primary cells and cell lines. Increased formation of puncta positive for the early autophagy markers WIPI2, RB1CC1/FIP200 and ATG16L1 indicates increased initiation of autophagy. The mycolactone response was SEC61A1-dependent and involved a pathway that required RB1CC1 but not ULK. Deletion of Sqstm1 reduced cell survival in the presence of mycolactone, suggesting this response protects against the increased cytosolic protein burden caused by the toxin. However, reconstitution of baseline SQSTM1 expression in cells lacking all autophagy receptor proteins could not rescue viability. Translational regulation by EIF2S1 in the ISR plays a key role in the autophagic response to mycolactone. Mycolactone-dependent induction of SQSTM1 was reduced in eif2ak3^−/-/perk^−/- cells while the p-EIF2S1 antagonist ISRIB reversed the upregulation of SQSTM1 and reduced RB1CC1, WIPI2 and LC3B puncta formation. Increased SQSTM1 staining could be seen in Buruli ulcer patient skin biopsy samples, reinforcing genetic data that suggests autophagy is relevant to disease pathology. Since selective autophagy and the ISR are both implicated in neurodegeneration, cancer and inflammation, the pathway uncovered here may have a broad relevance to human disease.

Abbreviations: ATF4: activating transcription factor 4; ATG: autophagy related; BAF: bafilomycin A₁; ATG16L1: autophagy related 16 like 1; BU: Buruli ulcer; CQ: chloroquine; EIF2AK3: eukaryotic translation initiation factor 2 alpha kinase 3; CALCOCO2: calcium binding and coiled-coil domain 2; DMSO: dimethyl sulfoxide; EIF2S1: eukaryotic translation initiation factor 2 subunit alpha; ER: endoplasmic reticulum; GFP: green fluorescent protein; HDMEC: human dermal microvascular endothelial cells; HFFF: human fetal foreskin fibroblasts; ISR: integrated stress response; ISRIB: integrated stress response inhibitor; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MEF: mouse embryonic fibroblast; Myco: mycolactone; NBR1: NBR1 autophagy cargo receptor; NFE2L2: nuclear factor, erythroid 2 like 2; OPTN: optineurin; PFA: paraformaldehyde; PtdIns3P: phosphatidylinositol-3-phosphate; RB1CC1: RB1-inducible coiled coil 1; SQSTM1: sequestosome 1; TAX1BP1: Tax1 binding protein 1; ULK: unc-51 like autophagy activating kinase; UPS: ubiquitin-proteasome system; WIPI: WD repeat domain, phosphoinositide interacting; WT: wild type.

Melatonin Alleviates Radiculopathy Against Apoptosis and NLRP3 Inflammasomes Via the Parkin-Mediated Mitophagy Pathway

STUDY DESIGN

Animal experimental study with intervention.

OBJECTIVE

To investigate the effect of melatonin on rat radiculopathy model and dorsal root ganglion (DRG) cells, and to elucidate the underlying mechanism.

SUMMARY OF BACKGROUND DATA

Melatonin has a well-documented efficacy in intervertebral disc degeneration (IVDD) and low back pain. IVDD can also lead to other complications such as disc herniation which will cause radiculopathy. Herniated nucleus pulposus (NP) induced apoptosis and NLR pyrin domain containing 3 (NLRP3) activation in DRG. However, the effect and underlying mechanism of melatonin on radiculopathy and DRG cells are still unclear.

METHODS

Rat radiculopathy model was induced by implanting NP tissue from the tail disc of the same rat into the left L4/5 inter-laminar space near the left DRG. Melatonin was injected intraperitoneally in the treated group to test its function. Apoptosis was determined by Tunnel staining and flow cytometry. NLRP3 inflammasome activation was determined by levels of NLRP3, ASC, GSMDM-N, IL-1β, and Caspase-1. Mitophagy was determined by levels of Parkin, Beclin-1, p62, and LCB-II. Mitophagy was blocked by treatment with Parkin-si or cyclosporine A (CsA).

RESULTS

NLRP3 was significantly upregulated in DRG of rat radiculopathy model; moreover, melatonin markedly decreased pain behavior in rat radiculopathy model. Furthermore, melatonin treatment decreases the incidence of apoptosis in DRG cells. Melatonin also promotes mitophagy and inhibits NLRP3 inflammasomes in DRG cells. In addition, mitophagy was blocked by treatment with Parkin-si and CsA. Both Parkin-si and CsA attenuated melatonin's inhibitory effect on apoptosis and the NLRP3 inflammasome, indicating that the beneficial effects of melatonin in DRG cells are mediated through the Parkin-mediated mitophagy.

CONCLUSION

Melatonin alleviates radiculopathy against apoptosis and NLRP3 inflammasomes by promoting Parkin-mediated mitophagy, which may help us provide a potential target for the treatment of radiculopathy.Level of Evidence: N/A.

Duocarmycin-based antibody-drug conjugates as an emerging biotherapeutic entity for targeted cancer therapy: Pharmaceutical strategy and clinical progress

Duocarmycins are a class of DNA minor-groove-binding alkylating molecules. For the past decade, various duocarmycin analogues have been used as payloads in the development of antibody-drug conjugates (ADCs). Currently, more than 15 duocarmycin-based ADCs have been studied preclinically, and some of them such as SYD985 have been granted Fast-Track Designation status. Nevertheless, progress in duocarmycin-based ADCs also faces challenges, with setbacks including the termination of BMS-936561/MDX-1203. In this review, we discuss issues associated with the efficacy, pharmacokinetic profile, and toxicological activity of these biotherapeutics. Furthermore, we summarize the latest advances in duocarmycin-based ADCs that have different target specificities and linker chemistries. Evidence from preclinical and clinical studies has indicated that duocarmycin-based ADCs are promising biotherapeutics for oncological application in the future.

An Examination of the Putative Role of Melatonin in Exosome Biogenesis

During the last two decades, melatonin has been found to have pleiotropic effects via different mechanisms on its target cells. Data are abundant for some aspects of the signaling pathways within cells while other casual mechanisms have not been adequately addressed. From an evolutionary perspective, eukaryotic cells are equipped with a set of interrelated endomembrane systems consisting of intracellular organelles and secretory vesicles. Of these, exosomes are touted as cargo-laden secretory vesicles that originate from the endosomal multivesicular machinery which participate in a mutual cross-talk at different cellular interfaces. It has been documented that cells transfer various biomolecules and genetic elements through exosomes to sites remote from the original cell in a paracrine manner. Findings related to the molecular mechanisms between melatonin and exosomal biogenesis and cargo sorting are the subject of the current review. The clarification of the interplay between melatonin and exosome biogenesis and cargo sorting at the molecular level will help to define a cell's secretion capacity. This review precisely addresses the role and potential significance of melatonin in determining the efflux capacity of cells via the exosomal pathway. Certain cells, for example, stem cells actively increase exosome efflux in response to melatonin treatment which accelerates tissue regeneration after transplantation into the injured sites.

Melatonin Protects HT22 Hippocampal Cells from H2O2-induced Injury by Increasing Beclin1 and Atg Protein Levels to Activate Autophagy

BACKGROUND

The aging of hippocampal neurons leads to a substantial decline in memory formation, storage and processing. The neuroprotective effect of melatonin has been confirmed, however, its protective mechanism remains unclear.

OBJECTIVE

In this study, mouse hippocampus-derived neuronal HT22 cells were used to investigate whether melatonin protects the hippocampus from hydrogen peroxide (H₂O₂)-induced injury by regulating autophagy.

METHODS

Rapamycin (an activator of autophagy) and 3-methyladenine (3MA, an inhibitor of autophagy) were used to induce or inhibit autophagy, respectively. HT22 cells were treated with 200 μM H₂O₂ in the presence or absence of 50 μM melatonin. Cell counting kit 8 (CCK-8), β-galactosidase and Hoechst staining were used to measure the viability, aging and apoptosis of cells, respectively. Western blot analysis was used to detect the levels of autophagy-related proteins.

RESULTS

The activation of autophagy by rapamycin alleviated H₂O₂-induced oxidative injury, as evidenced by morphological changes and decreased viability, while the inhibition of autophagy by 3MA exacerbated H₂O₂- induced injury. The inhibitory effect of melatonin on H₂O₂-induced injury was similar to that of rapamycin. Melatonin also alleviated H₂O₂-induced aging and apoptosis. Melatonin activated autophagy in the presence or absence of H₂O₂, as evidenced by an increased Lc3b 14/16 kd ratio and a decreased P62 level. In addition, H2O2 decreased the levels of Beclin1 and Atg5/12/16, which were reversed by rapamycin or melatonin. The effects of melatonin on H₂O₂-induced injury, autophagy and protein expressions were effectively reversed by 3MA.

CONCLUSION

In conclusion, these results demonstrate that melatonin protects HT22 hippocampal neurons from H₂O₂-induced injury by increasing the levels of the Beclin1 and Atg proteins to activate autophagy.

Melatonin ameliorates oxidative stress-mediated injuries through induction of HO-1 and restores autophagic flux in dry eye

This study aimed to investigate the protective effect of melatonin on the corneal epithelium in dry eye disease(DED) and explore its underlying mechanism. Human corneal epithelial(HCE) cells was exposure to t-butylhydroperoxide(tBH), C57BL/6 mice were injected of subcutaneous scopolamine to imitate DED. Melatonin was used both in vivo and in vitro. Cell viability was detected by Cell Counting Kit-8 assay and Lactate Dehydrogenase Leakage. The change of cellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and apoptosis was analyzed by flow cytometry. Western blot assays and immunofluorescence were carried out to measure protein changes. mRNA expression was investigated by RNA sequencing (RNA-Seq) and quantitative real-time PCR. The change of autophagic flux were observed through mCherry-GFP-LC3 transfection and electron microscopy(TEM). Clinical parameters of corneal epithelium defects, conjunctival goblet cells, tear volume, and level of ocular surface inflammation was recorded. Melatonin was able to reduce excessive ROS production and maintain mitochondrial function. TEM assay found melatonin rescued impaired autophagic flux under tBH. Moreover, melatonin significantly preserved cell viability, abolished LDH release, and decreased apoptosis. RNA-Seq indicated that melatonin greatly activating hemeoxygenase-1 (HO-1) expression. Interestingly, HO-1 ablation largely attenuated its protective effects. Besides, in dry eye mouse model, intraperitoneal injection of melatonin showed greatly improved clinical parameters, inhibited activated NLRP3 inflammation cascade, and increased density of goblet cells and tear volume. Thus, melatonin protects corneal epithelial cells from oxidative damage, maintain normal level of autophagy, and reduce inflammation via trigging HO-1 expression in DED.

Role of melatonin in the angiogenesis potential; highlights on the cardiovascular disease

Melatonin possesses multi-organ and pleiotropic effects with potency to control angiogenesis at both molecular and cellular levels. To date, many efforts have been made to control and regulate the dynamic of angiogenesis modulators in a different milieu. The term angiogenesis or neovascularization refers to the development of de novo vascular buds from the pre-existing blood vessels. This phenomenon is tightly dependent on the balance between the pro- and anti-angiogenesis factors which alters the functional behavior of vascular cells. The promotion of angiogenesis is thought to be an effective strategy to accelerate the healing process of ischemic changes such as infarcted myocardium. Of note, most of the previous studies have focused on the anti-angiogenesis capacity of melatonin in the tumor niche. To the best of our knowledge, few experiments highlighted the melatonin angiogenesis potential and specific regulatory mechanisms in the cardiovascular system. Here, we aimed to summarize some previous experiments related to the application of melatonin in cardiovascular diseases such as ischemic injury and hypertension by focusing on the regulatory mechanisms.

Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in patients with COVID-19 and healthy individuals

Stereotypic antibodies (Abs) are produced in healthy individuals by preexisting naïve B cells that have not undergone somatic hypermutation or class switching. Kim et al. have identified stereotypic neutralizing Abs (nAbs) against SARS-CoV-2 spike protein receptor binding domain (RBD) in healthy individuals and patients with COVID-19. They detected RBD-specific stereotypic variable heavy chain (V_H) Ab clonotypes composed of Ig heavy variable 3-53 (IGHV3-53) or IGHV3-66 and Ig heavy joining 6 (IGHJ6) genes in 13 of 17 patients with COVID-19. One stereotypic nAb could inhibit in vitro replication of a clinical isolate of SARS-CoV-2. These V_H clonotypes were also found in 6 of 10 healthy individuals with no evidence of exposure to SARS-CoV-2, and together, these findings provide evidence of the presence of preexisting nAbs to SARS-CoV-2.

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 of 17 patients with COVID-19 had stereotypic variable heavy chain (V_H) antibody clonotypes directed against the receptor binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were composed of immunoglobulin heavy variable 3-53 (IGHV3-53) or IGHV3-66 and immunoglobulin heavy joining 6 (IGHJ6) genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different IGHV chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these V_H clonotypes existed in 6 of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

RNA-binding protein HuR suppresses senescence through Atg7 mediated autophagy activation in diabetic intervertebral disc degeneration

Objectives

Diabetes is a risk factor for intervertebral disc degeneration (IVDD). Studies have demonstrated that diabetes may affect IVDD through transcriptional regulation; however, whether post‐transcriptional regulation is involved in diabetic IVDD (DB‐IVDD) is still unknown. This study was performed to illustrate the role of HuR, an RNA‐binding protein, in DB‐IVDD development and its mechanism.

Materials and Methods

The expression of HuR was evaluated in nucleus pulposus (NP) tissues from diabetic IVDD patients and in high glucose‐treated NP cells. Senescence and autophagy were assessed in HuR over‐expressing and downregulation NP cells. The mRNAs that were regulated by HuR were screened, and immunoprecipitation was applied to confirm the regulation of HuR on targeted mRNAs.

Results

The results showed that the expression of HuR was decreased in diabetic NP tissues and high glucose‐treated NP cells. Downregulation of HuR may lead to increased senescence in high glucose‐treated NP cells, while autophagy activation attenuates senescence in HuR deficient NP cells. Mechanistic study showed that HuR prompted Atg7 mRNA stability via binding to the AU‐rich elements. Furthermore, overexpression of Atg7, but not HuR, may ameliorate DB‐IVDD in rats in vivo.

Conclusions

In conclusion, HuR may suppress senescence through autophagy activation via stabilizing Atg7 in diabetic NP cells; while Atg7, but not HuR, may serve as a potential therapeutic target for DB‐IVDD.

Sesn2 attenuates the damage of endothelial progenitor cells induced by angiotensin II through regulating the Keap1/Nrf2 signal pathway

Endothelial progenitor cell (EPC) dysfunction is an important physiopathological mechanism in the dynamics of the formation of atherosclerosis. It has been reported that angiotensin II (Ang-II) damages the function of EPCs in atherosclerotic plaque through induction of oxidative stress. Sestrin 2 (Sesn2) serves as an antioxidant role in oxidative stress, however, the exact mechanisms underlying the dynamics of how Sesn2 may factor into EPCs after Ang-II treatments needs to be illustrated. We isolated EPCs from human umbilical cord blood samples and treated with Ang-II. Western blotting, qRT-PCR, transwell assays, immunofluorescence and so on were used to investigate the mechanisms underlying the roles of Sesn2 in EPCs treated with Ang-II. Ang-II was found to promote the apoptosis of EPCs as well as inhibited the mRNA and protein expression of Sesn2. Upregulation of Sesn2 attenuated the negative effect of Ang-II. Sesn2 increased the protein expression of Nrf2 by enhancing P62-dependent autophagy. Silencing of Nrf2 enhanced the degree of apoptosis of EPCs as well as resulted in the impairment of EPC functions through inducing the promotion of (reactive oxygen species) ROS production. Our study results indicated that Sesn2 facilitated the viability of EPCs After treatment with Ang-II, as well as provided a potential therapeutic target to alleviate the progression of atherosclerosis.

Melatonin upregulates DNA-PKcs to suppress apoptosis of human umbilical vein endothelial cells via inhibiting miR-101 under H2O2-induced oxidative stress

Melatonin has been implicated in inhibiting oxidative stress-induced apoptosis of endothelial cells. However, the underlying mechanism remains poorly understood. In this study, we examined the effect of melatonin on apoptosis of human umbilical vein endothelial cells (HUVECs) induced by H₂O₂ and explored the underlying mechanisms. Our results demonstrated that DNA-dependent protein kinase catalytic subunit (DNA-PKcs) upregulation contributed to the protective role of melatonin in HUVECs under oxidative stress with H₂O₂. Further study showed that melatonin treatment led to a decreased level of miRNA-101, which could be responsible for DNA-PKcs upregulation and DNA-PKcs-mediated apoptosis inhibition in HUVECs under oxidative stress with H₂O₂. Our results also showed that melatonin increased the activity of PI3K/AKT and DNA-PKcs knockdown in melatonin-treated HUVECs that lead to inactivation of PI3K/AKT signaling under oxidative stress with H₂O₂. Furthermore, blockade of PI3K/AKT signal with LY294002 significantly reduced melatonin-induced apoptosis inhibition in H₂O₂-treated HUVECs. Taken together, our findings identify a miR-101/DNA-PKcs/PI3K/AKT signaling pathway in melatonin-induced endothelial cell apoptosis inhibition under oxidative stress with H₂O₂.

How can the potential of the duocarmycins be unlocked for cancer therapy?

The duocarmycins belong to a class of agent that has fascinated scientists for over four decades. Their exquisite potency, unique mechanism of action, and efficacy in multidrug-resistant tumour models makes them attractive to medicinal chemists and drug hunters. However, despite great advances in fine-tuning biological activity through structure-activity relationship studies (SARS), no duocarmycin-based therapeutic has reached clinical approval. In this review, we provide an overview of the most promising strategies currently used and include both tumour-targeted prodrug approaches and antibody-directed technologies.

Procyanidin B2 improves endothelial progenitor cell function and promotes wound healing in diabetic mice via activating Nrf2

One of the major reasons for the delayed wound healing in diabetes is the dysfunction of endothelial progenitor cells (EPCs) induced by hyperglycaemia. Improvement of EPC function may be a potential strategy for accelerating wound healing in diabetes. Procyanidin B2 (PCB2) is one of the major components of procyanidins, which exhibits a variety of potent pharmacological activities. However, the effects of PCB2 on EPC function and diabetic wound repair remain elusive. We evaluated the protective effects of PCB2 in EPCs with high glucose (HG) treatment and in a diabetic wound healing model. EPCs derived from human umbilical cord blood were treated with HG. The results showed that PCB2 significantly preserved the angiogenic function, survival and migration abilities of EPCs with HG treatment, and attenuated HG‐induced oxidative stress of EPCs by scavenging excessive reactive oxygen species (ROS). A mechanistic study found the protective role of PCB2 is dependent on activating nuclear factor erythroid 2‐related factor 2 (Nrf2). PCB2 increased the expression of Nrf2 and its downstream antioxidant genes to attenuate the oxidative stress induced by HG in EPCs, which were abolished by knockdown of Nrf2 expression. An in vivo study showed that intraperitoneal administration of PCB2 promoted wound healing and angiogenesis in diabetic mice, which was accompanied by a significant reduction in ROS level and an increase in circulating EPC number. Taken together, our results indicate that PCB2 treatment accelerates wound healing and increases angiogenesis in diabetic mice, which may be mediated by improving the mobilization and function of EPCs.

The Impact of Advanced Glycation End-Products (AGEs) on Proliferation and Apoptosis of Primary Stem Cells: A Systematic Review

Stem cell-based regenerative therapies hold great promises to treat a wide spectrum of diseases. However, stem cell engraftment and survival are still challenging due to an unfavorable transplantation environment. Advanced glycation end-products (AGEs) can contribute to the generation of these harmful conditions. AGEs are a heterogeneous group of glycated products, nonenzymatically formed when proteins and/or lipids become glycated and oxidized. Our typical Western diet as well as cigarettes contain high AGEs content. AGEs are also endogenously formed in our body and accumulate with senescence and in pathological situations. Whether AGEs have an impact on stem cell viability in regenerative medicine remains unclear, and research on the effect of AGEs on stem cell proliferation and apoptosis is still ongoing. Therefore, this systematic review provides a clear overview of the effects of glycated proteins on cell viability in various types of primary isolated stem cells used in regenerative medicine.

Kanglexin accelerates diabetic wound healing by promoting angiogenesis via FGFR1/ERK signaling

Diabetic foot is one of the main causes of non-traumatic amputation. However, there is still lack of effective drugs to treat diabetic foot in clinical practice. Kanglexin (KLX) is a new anthraquinone compound with cardiovascular protective effects. Here we report that KLX accelerates diabetic wound healing by promoting angiogenesis via FGFR1/ERK signaling. Firstly, KM mice were injected (ip) with streptozocin to establish type 1 diabetic model. The full thickness wound with the diameter of 5 mm was prepared on the back of each mice. The wounds were treated with KLX once a day for 14 consecutive days. Results showed that KLX significantly accelerated the closure of diabetic wounds. Pathological studies of skin tissues around the wounds showed that KLX promoted the formation of granulation tissue and new blood vessels, increased collagen deposition and reduced inflammatory cell infiltration. Besides, KLX significantly alleviated advanced glycation end products (AGEs) - induced abnormal proliferation, migration and tubule formation of human umbilical vein endothelial cells (HUVECs), and up-regulated phospho-ERK1/2 both in the diabetic wound tissue and AGEs - treated HUVECs. Moreover, molecular docking results indicated that KLX had the potential to bind with FGF receptor 1 (FGFR1), and subsequent experiments confirmed that FGFR1 inhibitor PD173074 reversed the effect of KLX on promoting the phosphorylation of ERK1/2 and angiogenesis, suggesting that KLX promoted angiogenesis through FGFR1/ERK signaling. In conclusion, our study provides a new effective compound for treating diabetic wounds. More importantly, KLX has the potential to be developed as a topical drug to promote diabetic wound healing.

TUG1 enhances high glucose-impaired endothelial progenitor cell function via miR-29c-3p/PDGF-BB/Wnt signaling

BACKGROUND

Diabetes is associated with the dysfunction of endothelial progenitor cells (EPCs), characterized as impaired angiogenesis, a phenomenon thought to be involved in the development of diabetic foot. lncRNA plays an essential role in microvascular dysfunction and signaling pathways in patients with diabetes. lncRNA taurine upregulated gene 1 (TUG1) participates in angiogenesis in various cells. However, the mechanisms of TUG1 activity in EPCs have not been elucidated.

METHODS

We isolated and then characterized EPCs from the peripheral blood of mice using immunofluorescence and flow cytometry. Western blot detected the wnt/β-catenin pathway in high glucose-treated EPCs. Bioinformatics analysis predicted a putative binding site for TUG1 on miR-29c-3p. The interactions among TUG1, platelet-derived growth factor-BB (PDGF-BB), and miR-29c-3p were analyzed by luciferase assays. In vivo, diabetic mouse ischemic limb was treated with normal saline or TUG1 overexpression lentiviruses.

RESULTS

We found that EPC migration, invasion, and tube formation declined after treatment with high glucose, but improved with TUG1 overexpression. Mechanically, wnt/β-catenin pathway and autophagy were involved in the function of TUG1 overexpression in high glucose-treated EPCs. Moreover, TUG1 regulates the PDGF-BB/wnt pathway and function of high glucose-treated EPCs via miR-29c-3p. In vivo, injection of TUG1 lentivirus in a diabetic mouse ischemic limb model stimulated angiogenesis.

CONCLUSIONS

Our findings suggest that TUG1 restores high glucose-treated EPC function by regulating miR-29c-3p/PDGF-BB/Wnt signaling.

Skin wound healing assisted by angiogenic targeted tissue engineering: A comprehensive review of bioengineered approaches

Skin injuries and in particular, chronic wounds, are one of the major prevalent medical problems, worldwide. Due to the pivotal role of angiogenesis in tissue regeneration, impaired angiogenesis can cause several complications during the wound healing process and skin regeneration. Therefore, induction or promotion of angiogenesis can be considered as a promising approach to accelerate wound healing. This article presents a comprehensive overview of current and emerging angiogenesis induction methods applied in several studies for skin regeneration, which are classified into the cell, growth factor, scaffold, and biological/chemical compound-based strategies. In addition, the advantages and disadvantages of these angiogenic strategies along with related research examples are discussed in order to demonstrate their potential in the treatment of wounds.

Role of Melatonin in the Synchronization of Asexual Forms in the Parasite Plasmodium falciparum

The indoleamine compound melatonin has been extensively studied in the regulation of the circadian rhythm in nearly all vertebrates. The effects of melatonin have also been studied in Protozoan parasites, especially in the synchronization of the human malaria parasite Plasmodium falciparum via a complex downstream signalling pathway. Melatonin activates protein kinase A (PfPKA) and requires the activation of protein kinase 7 (PfPK7), PLC-IP₃, and a subset of genes from the ubiquitin-proteasome system. In other parasites, such as Trypanosoma cruzi and Toxoplasma gondii, melatonin increases inflammatory components, thus amplifying the protective response of the host’s immune system and affecting parasite load. The development of melatonin-related indole compounds exhibiting antiparasitic properties clearly suggests this new and effective approach as an alternative treatment. Therefore, it is critical to understand how melatonin confers stimulatory functions in host–parasite biology.

Neoadjuvant Radiotherapy-Related Wound Morbidity in Soft Tissue Sarcoma: Perspectives for Radioprotective Agents

Historically, patients with localized soft tissue sarcomas (STS) of the extremities would undergo limb amputation. It was subsequently determined that the addition of radiation therapy (RT) delivered prior to (neoadjuvant) or after (adjuvant) a limb-sparing surgical resection yielded equivalent survival outcomes to amputation in appropriate patients. Generally, neoadjuvant radiation offers decreased volume and dose of high-intensity radiation to normal tissue and increased chance of achieving negative surgical margins-but also increases wound healing complications when compared to adjuvant radiotherapy. This review elaborates on the current neoadjuvant/adjuvant RT approaches, wound healing complications in STS, and the potential application of novel radioprotective agents to minimize radiation-induced normal tissue toxicity.

Age-dependent altered redox homeostasis in the chronodisrupted rat model and moderation by melatonin administration

Circadian disruption or chronodisruption (CD) occurs when day-night cycles and other internal rhythms are not adjusted to environmental light-dark regimens and are unable to synchronize among each other. Artificial light-induced oxidative stress is a major concern as the circadian physiology of the cell is chronically altered due to suppression of the time-keeping hormone, melatonin. The relationship between age-related impaired redox status and disrupted circadian rhythms is still not fully understood. The present study evaluated the effect of artificial light at night (ALAN) with respect to aging and role of melatonin supplementation. This study was conducted on young (3 months) and old (24 months) male Wistar rats subdivided into four groups control (C), melatonin treated (MLT), artificial light at night (ALAN), and ALAN+MLT group. Pronounced changes were observed in the old compared to the young rats. Reactive oxygen species (ROS), malondialdehyde (MDA), plasma membrane redox system (PMRS), protein carbonyl (PCO), and sialic acid (SA) were significantly (p ≤ 0.05) increased, while ferric reducing ability of plasma (FRAP) and reduced glutathione (GSH) were significantly (p ≤ 0.05) suppressed in light-exposed young and old animals compared to their age-matched controls. Advanced oxidation protein products (AOPP) increased non-significantly in young rats of the ALAN group; however, significant (p ≤ 0.05) changes were observed in the old rats of the ALAN group compared to their respective controls. Advanced glycation end products (AGEs) increased and acetylcholinesterase (AChE) activity decreased, significantly (p ≤ 0.05) in young animals of the ALAN group, while nonsignificant changes of both parameters were recorded in the old animals of the ALAN groups compared with their age-matched controls. Melatonin supplementation resulted in maintenance of the normal redox homeostasis in both young and old animal groups. Our study suggests that aged rats are more susceptible to altered photoperiod as their circadian redox homeostasis is under stress subsequent to ALAN. Melatonin supplementation could be a promising means of alleviating age-related circadian disturbances, especially in light-polluted areas.

Bafilomycin A1 Accelerates Chronic Refractory Wound Healing in db/db Mice

Numerous studies have reported that autophagy plays an important role in chronic wound healing, and enhancement of autophagic activity impairs cutaneous wound healing. The autophagy inhibitor Bafilomycin A1 (Baf A1) inhibits autophagy by preventing the formation of autophagosomes. This study aimed at elucidating the effect of Bafilomycin A1 on chronic refractory wound healing in diabetic mice. A total of 40 diabetic (db/db) mice and 20 nondiabetic (db/m) mice were used in this study. Full-thickness skin defects were generated in the db/db mice models, which were then divided into the following two groups: the nontreated (db/db group) and Baf A1-treated groups (Baf A1 group). The same skin defects were generated in db/m mice (db/m group) to serve as a control. We demonstrated that Baf A1 treatment significantly accelerated wound healing in db/db mice and exerted good healing effects. Moreover, Baf A1 inhibited autophagy in the newly generated epidermis and had minor effects on metabolism in db/db mice. PCNA expression, as detected by immunohistochemistry, and collagen thickness, as detected by Masson's trichrome staining on the 14th day, were higher in the db/m and Baf A1 groups than in the db/db group. In addition, the expression of the proinflammatory cytokine TNF-α in the db/m and Baf A1 groups increased significantly on day 6, and the expression of the anti-inflammatory cytokine IL-10 also increased significantly on day 9. However, there were no significant changes in the expression levels of TNF-α and IL-10 in the db/db group. Therefore, Baf A1 may accelerate diabetic chronic refractory wound healing by promoting cell proliferation, collagen production, and regulating the inflammatory balance.

hsa_circ_0058092 protects against hyperglycemia‑induced endothelial progenitor cell damage via miR‑217/FOXO3

Circular RNAs (circRNAs) regulate the expression of genes that are critical for various biological and pathological processes. Previous studies have reported that the expression of hsa_circ_0058092 is decreased in patients with diabetes mellitus (DM); however, the specific role of this circRNA in DM is unknown. In the present study, endothelial progenitor cells (EPCs) were isolated and a decreased hsa_circ_0058092 expression was found under conditions of hyperglycemia (HG). The overexpression of hsa_circ_0058092 protected the EPCs against HG‑induced damage by preserving cell survival, proliferation, migration and angiogenic differentiation. The overexpression of hsa_circ_0058092 also decreased the HG‑induced increase in NADPH‑oxidase proteins and inflammatory cytokines. Further investigation revealed that the overexpression of hsa_circ_0058092 enhanced FOXO3 expression, which was mediated through the interaction with miR‑217. Furthermore, the upregulation of miR‑217 or the downregulation of FOXO3 abolished the protective effects of hsa_circ_0058092 against HG‑induced EPC damage. On the whole, these data suggest that hsa_circ_0058092 acts via the miR‑217/FOXO3 pathway to protect against EPCs HG‑induced damage, and to preserve the migration and angiogenesis of EPCs.

Melatonin inhibits Benzo(a)pyrene-Induced apoptosis through activation of the Mir-34a/Sirt1/autophagy pathway in mouse liver

Benzo(a)pyrene (BaP), an important environmental pollutant, is produced as the result of incomplete combustion of organic materials in many industries and food cooking process. It has been purposed that BaP induces hepatotoxicity through oxidative stress and apoptosis. Several studies have shown that melatonin can protect against chemical-induced apoptosis through autophagy pathway. In this study, we assessed the modulating effect of melatonin, a well-known antioxidant, on BaP-induced hepatotoxicity through induction of autophagy. Thirty male mice were treated daily for 28 consecutive days. BaP (75 mg/kg; oral gavage) and melatonin (10 and 20 mg/kg, i.p.) were administered to mice. The liver histopathology and the levels of apoptosis and autophagy proteins as well as the expression of miR-34a were determined. The BaP exposure induced severe liver histological injury and markedly enhanced AST, ALT and MDA level. Also, apoptosis proteins and hepatic miR-34a expression increased. However, the level of Sirt1 and autophagy markers such as LC3 II/I ratio and Beclin-1 reduced. The co-administration of melatonin reversed all changes caused by BaP. In summary, melatonin appears to be effective in BaP-induced hepatotoxicity maybe through the miR-34a/Sirt1/autophagy molecular pathway.

Expression of miR-210 in the peripheral blood of patients with newly diagnosed type 2 diabetes mellitus and its effect on the number and function of endothelial progenitor cells

OBJECTIVE

This study aims to investigate the correlation between the expression of miR-210 in peripheral blood and the number of peripheral endothelial progenitor cells (EPCs) in patients with type 2 diabetes mellitus (T2DM). We also determined the effect of miR-210 on EPC proliferation, adhesion, migration, tube formation, and apoptosis.

METHODS

A total of 32 patients with newly diagnosed T2DM (T2DM group) and 32 control subjects with normal glucose tolerance (NC group) were included. Peripheral blood samples were collected from each subject. The miR-210 level was determined by quantitative real-time polymerase chain reaction (qRT-PCR), and the number of positive EPCs indicated by CD34, CD133, and KDR expressions was detected by flow cytometry. After isolation, culture, and identification by fluorescent staining, EPCs were divided into four groups: NC group, untransfected type 2 diabetic group, miR-210 inhibitor NC group, and miR-210 inhibitor group. The expression of miR-120 in each group was detected by qRT-PCR, and the changes in the proliferation, adhesion, migration, tube formation, and apoptosis of EPCs after transfection with a miR-210 inhibitor were observed.

RESULTS

The expression level of miR-210 in the T2DM group (5.83 ± 1.26) was significantly higher than that in the NC group (1.18 ± 0.54) (t = 17.26, P < 0.001). The number of EPCs was significantly lower in the T2DM group (39.3 ± 12.6)/10⁶ cells than that in the NC group (76.2 ± 10.7)/10⁶ cells (t = 10.49, P < 0.001). Spearman's correlation analysis showed that the expression of miR-210 in the peripheral blood of patients with T2DM was negatively correlated with the number of EPCs (r = -0.558, P = 0.001). Multiple linear stepwise regression analysis showed that the peripheral blood level of miR-210 was an independent correlation factor that affected the number of EPCs (P < 0.001). After transfection with the miR-210 inhibitor, the proliferation, adhesion, tube formation, and migration levels of EPCs in miR-210 inhibitor group were higher than those in untransfected type 2 diabetic group and miR-210 inhibitor NC group, whereas the apoptosis rate was lower than that in these groups, and these results were statistically significant (P < 0.05).

CONCLUSION

The increased expression of miR-210 in patients with T2DM may be related to the decreased number and function of EPCs in peripheral blood.

Neuroprotection of melatonin on spinal cord injury by activating autophagy and inhibiting apoptosis via SIRT1/AMPK signaling pathway

The effect of melatonin (MT) on spinal cord injury (SCI) has attracted increasing research attention. However, the specific role and molecular mechanism of MT on SCI have not been elucidated. An experiment was performed to investigate the effect and molecular mechanism of MT on the neuronal autophagy after SCI and its effect on the recovery of nerve function. The rats were randomly divided into four treatment groups: the SCI+MT+EX527 (SIRT1 inhibitor), SCI+MT, SCI, and sham operation groups. On the 14th day after SCI, MT significantly promoted the recovery of motor function in the hind limbs according to the results of Basso, Beattie, and Bresnahan scores. At the same time, MT treatment resulted in reduced activation of cleaved-caspase-3, cleaved-caspase-9, and terminal deoxynucleotidyl transferase dUTP nick end labeling-positive neurons and increased the survival of motoneurons in the anterior horn of the spinal cord on the 14th day after SCI, which exerted its neuroprotection. Furthermore, western blot and immunofluorescence double staining were performed to verify the molecular mechanism of effect of MT on SCI, and results showed the significantly upregulated expressions of Beclin-1, light chain-3B, SIRT1, p-AMPK proteins in the spinal cord tissue of MT-treated rats on the 14th day after SCI, however, the effect of MT on autophagy was reversed by EX527 (SIRT1 inhibitor), which implied that MT activated autophagy via SIRT1/AMPK signaling pathway after SCI. Similarly, the neuroprotective effects of MT on SCI were also inhibited after the SIRT1/AMPK signaling pathway was suppressed by EX527. Taken together, these results suggest that MT inhibits the apoptosis and activates autophagy of nerve cells after SCI and ultimately exerts the neuroprotective effect by SIRT1/AMPK signaling pathway.

Investigation on the influence of isolated environment on human psychological and physiological health

Crewmembers are working and living in isolated environment lacking natural light and perception. Although their health problems have been documented, the mechanism has not been thoroughly investigated. The aim of the present study is to investigate the psychological and physiological influences of isolated environment on crewmember's health. On account of complexity of the isolated environment, it is necessary to have a manually controllable system to simulate research platform-Bioregenerative Life Support System (BLSS). Symptom checklist 90 (SCL-90) was used to complete emotional status test. Urine samples were collected for metabonomics and hormone secretion analysis. Fecal samples were collected for intestinal microorganisms analysis. Crewmembers (n = 4) followed strict daily schedule during the experimental period. Five emotional factors were significantly (P < 0.05) increased, differential metabolites were enriched in tryptophan metabolism pathway, the relative abundance of Prevotella decreased significantly (P < 0.0001) when crewmembers in isolated environment without natural light. Hormone (melatonin, cortisol) secretion rhythm also changed. Significant positive correlation (r = 0.805, P < 0.05) between cortisol secretion and anxiety was observed. In conclusion, natural light simulation in an isolated environment may have a positive effect on the physiological and psychological health of the crewmember.

Melatonin attenuates vascular calcification by activating autophagy via an AMPK/mTOR/ULK1 signaling pathway

Melatonin has been demonstrated to protect against calcification in cyclosporine nephrotoxicity. Autophagy may affect vascular calcification by inhibiting apoptosis and the transdifferentiation process. This study sought to explore whether melatonin attenuates vascular calcification by regulating autophagy via the AMP-activated protein kinase/mammalian target of rapamycin/Unc-51-like kinase 1 (AMPK/mTOR/ULK1) signaling pathway. The effects of melatonin on vascular calcification were investigated in vascular smooth muscle cells (VSMCs). Calcium deposits were visualised by Alizarin red staining, while calcium content and alkaline phosphatase (ALP) activity were used to evaluate osteogenic differentiation. Western blots were used to measure expression of runt-related transcription factor 2 (Runx2, an osteogenic transcription factor), light chain 3 (LC3) II/I, and cleaved caspase 3. Melatonin markedly reduced calcium deposition and ALP activity. Runx2 and cleaved caspase 3 were downregulated, whereas LC3 II/I was increased in response to melatonin, and was accompanied by decreased apoptosis. An immunofluorescence assay revealed that melatonin treatment markedly decreased Runx2 expression and upregulated LC3 expression. Treatment with the autophagy inhibitor 3-methyladenine reversed this phenomenon. Melatonin significantly increased expression of p-AMPK and p-ULK1, and decreased mTOR expression. Treatment with compound C (an inhibitor of AMPK) or MHY1485 (an agonist of mTOR) ablated the observed benefits of melatonin treatment. Melatonin protects VSMCs against calcification by activating autophagy via the AMPK/mTOR/ULK1 pathway.