High levels of pigment epithelium-derived factor in diabetes impair wound healing through suppression of Wnt signaling

Association of Obesity and Bariatric Surgery on Hair Health

Obesity and obesity-related conditions today constitute a public health problem worldwide. Obesity is an "epidemic" chronic disorder, which is defined by the WHO as normal or excessive fat accumulation that may impair health. It is also defined for adults as a BMI that is greater than or equal to 30. The most common obesity-related diseases are type 2 diabetes mellitus, cardiovascular diseases, metabolic syndrome, chronic kidney disease, hyperlipidemia, hypertension, nonalcoholic fatty liver disease, and certain types of cancer. It has been also proven that obesity can have a negative effect on hair. It can lead to hair thinning. Patients with obesity can undergo bariatric surgery if they meet the inclusion criteria. The four common types of weight loss surgery include a duodenal switch with biliopancreatic diversion, laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, and sleeve gastrectomy. Bariatric surgery can affect skin and hair and is associated with telogen effluvium due to weight loss, microelement deficiency, anesthesia, low calorie intake, and low protein intake. Patients who undergo bariatric surgery can experience post-bariatric surgery depression. Hair loss can have a major impact on self-esteem, negatively affecting one's self-image. The purpose of this narrative review is to critically review how obesity, obesity-related diseases, and bariatric surgery affect hair health in general and the hair development cycle, and how they influence hair loss.

Discovery of β-sitosterol's effects on molecular changes in rat diabetic wounds and its impact on angiogenesis and macrophages

Diabetes care, particularly for diabetic foot ulcers (DFUs)-related complications, increases treatment costs substantially. Failure to provide timely and appropriate treatment for severe DFUs significantly increases amputation risk. Neovascularization and macrophage polarization play an important role in diabetic wound healing during different stages of the wound repair process. Therefore, a new treatment method that promotes neovascularization and macrophage polarization may accelerate diabetic wound healing. β-sitosterol possesses anti-inflammatory, lipid-lowering, and antidiabetic properties. However, its therapeutic potential in diabetic wound healing remains underexplored. This study evaluated the healing effects of β-sitosterol on diabetic ulcer wounds in rats. We found that β-sitosterol can promote angiogenesis, alternatively activated macrophages (M2 macrophage) proliferation, and collagen synthesis in diabetic wounds. Transcriptomics analysis and proteomics analysis revealed that MAPK, mTOR and VEGF signaling pathways were enriched in β-sitosterol-treated wounds. Molecular docking revealed Ndufb5 maybe the target of β-sitosterol-treated wounds. Our findings confirm the significant diabetic wound healing effects of β-sitosterol in a rat model. β-sitosterol treatment to diabetic wounds accelerates wound healing through promoting M2 macrophage proliferation and angiogenesis. Interestingly, we also found that the process of M2 macrophage proliferation accompanies angiogenesis. Thus, β-sitosterol may be a promising therapeutic approach to enhance diabetic wound healing and reduce amputation in diabetes.

Pigment Epithelium-Derived Factor, a Novel Adipokine, Contributes to Gestational Diabetes Mellitus

CONTEXT

Excessive insulin resistance, inadequate insulin compensation, or both could result in gestational diabetes mellitus (GDM). Levels of pigment epithelium-derived factor (PEDF), a novel adipokine that could induce insulin resistance, are high in patients with obesity and diabetes. However, the impact of PEDF in pregnancy remains unknown.

OBJECTIVE

This study aimed to elucidate the role of PEDF on insulin resistance and compensatory elevation of insulin levels during normal pregnancy and in patients with GDM.

METHODS

In this population-based and cohort study, logistic regression analysis was performed to determine the association of PEDF/adiponectin/leptin levels with the risk of developing GDM and to predict postpartum prediabetes. PEDF protein, PEDF transgenic mice, PEDF knockout mice, and PEDF-neutralized antibodies were used to observe changes in insulin resistance and insulin levels with pregnancy.

RESULTS

Plasma PEDF levels were increased in normal pregnancy and higher in GDM women. Higher PEDF levels were associated with the increased risk of developing GDM and emerged as a significant independent determinant of postpartum prediabetes in GDM women. Mechanistically, in vivo and in vitro experiments revealed that PEDF induced insulin resistance by inhibiting the insulin signaling pathway.

CONCLUSION

In addition to insulin resistance and upregulated insulin levels in normal pregnancy and GDM, aberrant PEDF levels can serve as a "fingerprint" of metabolic abnormalities during pregnancy. Thus, PEDF is a valuable biomarker but could interfere with the time course for early diagnosis and prognosis of GDM.

Targeting Signalling Pathways in Chronic Wound Healing

Chronic wounds fail to achieve complete closure and are an economic burden to healthcare systems due to the limited treatment options and constant medical attention. Chronic wounds are characterised by dysregulated signalling pathways. Research has focused on naturally derived compounds, stem-cell-based therapy, small molecule drugs, oligonucleotide delivery nanoparticles, exosomes and peptide-based platforms. The phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT), Wingless-related integration (Wnt)/β-catenin, transforming growth factor-β (TGF-β), nuclear factor erythroid 2-related factor 2 (Nrf2), Notch and hypoxia-inducible factor 1 (HIF-1) signalling pathways have critical roles in wound healing by modulating the inflammatory, proliferative and remodelling phases. Moreover, several regulators of the signalling pathways were demonstrated to be potential treatment targets. In this review, the current research on targeting signalling pathways under chronic wound conditions will be discussed together with implications for future studies.

Molecular pathways of NF-ĸB and NLRP3 inflammasome as potential targets in the treatment of inflammation in diabetic wounds: A review

Diabetic wounds are slow healing wounds characterized by disordered healing processes and frequently take longer than three months to heal. One of the defining characteristics of impaired diabetic wound healing is an abnormal and unresolved inflammatory response, which is primarily brought on by abnormal macrophage innate immune signaling activation. The persistent inflammatory state in a diabetic wound may be attributed to inflammatory pathways such as nuclear factor kappa B (NF-ĸB) and nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which have long been associated with inflammatory diseases. Despite the available treatments for diabetic foot ulcers (DFUs) that include debridement, growth factor therapy, and topical anti-bacterial agents, successful wound healing is still hampered. Further understanding of the molecular mechanism of these pathways could be useful in designing potential therapeutic targets for diabetic wound healing. This review provides an update and novel insights into the roles of NF-ĸB and NLRP3 pathways in the molecular mechanism of diabetic wound inflammation and their potential as therapeutic targets in diabetic wound healing.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

Diabetes mellitus (DM) constitutes a chronic metabolic disease characterized by elevated levels of blood glucose which can also lead to the so-called diabetic vascular complications (DVCs), responsible for most of the morbidity, hospitalizations and death registered in these patients. Currently, different approaches to prevent or reduce DM and its DVCs have focused on reducing blood sugar levels, cholesterol management or even changes in lifestyle habits. However, even the strictest glycaemic control strategies are not always sufficient to prevent the development of DVCs, which reflects the need to identify reliable biomarkers capable of predicting further vascular complications in diabetic patients. Endothelial progenitor cells (EPCs), widely known for their potential applications in cell therapy due to their regenerative properties, may be used as differential markers in DVCs, considering that the number and functionality of these cells are affected under the pathological environments related to DM. Besides, drugs commonly used with DM patients may influence the level or behaviour of EPCs as a pleiotropic effect that could finally be decisive in the prognosis of the disease. In the current review, we have analysed the relationship between diabetes and DVCs, focusing on the potential use of EPCs as biomarkers of diabetes progression towards the development of major vascular complications. Moreover, the effects of different drugs on the number and function of EPCs have been also addressed.

Novel mediators regulating angiogenesis in diabetic foot ulcer healing

A non-healing diabetic foot ulcer (DFU) is a debilitating clinical problem amounting to socioeconomic and psychosocial burdens. DFUs increase morbidity due to prolonged treatment and mortality in the case of non-treatable ulcers resulting in gangrene and septicemia. The overall amputation rate of the lower extremity with DFU ranges from 3.34% to 42.83%. Wound debridement, antibiotics, applying growth factors, negative pressure wound therapy, hyperbaric oxygen therapy, topical oxygen, and skin grafts are common therapies for DFU. However, recurrence and nonhealing ulcers are still major issues. Chronicity of inflammation, hypoxic environment, poor angiogenesis, and decreased formation of the extracellular matrix (ECM) are common impediments leading to nonhealing patterns of DFUs. Angiogenesis is crucial for wound healing since proper vessel formation facilitates nutrients, oxygen, and immune cells to the ulcer tissue to help in clearing out debris and facilitate healing. However, poor angiogenesis due to decreased expression of angiogenic mediators and matrix formation results in nonhealing and ultimately amputation. Multiple proangiogenic mediators and vascular endothelial growth factor (VEGF) therapy exist to enhance angiogenesis, but the results are not satisfactory. Thus, there is a need to investigate novel pro-angiogenic mediators that can either alone or in combination enhance the angiogenesis and healing of DFUs. In this article, we critically reviewed the existing pro-angiogenic mediators followed by potentially novel factors that might play a regulatory role in promoting angiogenesis and wound healing in DFUs.

Self-powered enzyme-linked microneedle patch for scar-prevention healing of diabetic wounds

Diabetic wounds with complex pathological features and a difficult-to-heal nature remain a formidable challenge. To address this challenge, we design and fabricate a self-powered enzyme-linked microneedle (MN) patch composed of anode and cathode MN arrays, which respectively contain glucose oxidase (GOx) and horseradish peroxidase (HRP) encapsulated in ZIF-8 nanoparticles. The enzymatic cascade reaction in the MN patch can effectively reduce local hyperglycemia in diabetic wounds while generating stable microcurrents to promote rapid healing of diabetic wounds. Therefore, the diabetic wounds treated with this MN patch exhibit rapid, complete, and scar-preventative healing, which can be attributed to the synergistic actions of hypoglycemic, antibacterial, anti-inflammatory, and bioelectrical stimulation. In brief, the self-powered MN patch is an effective method to rapidly promote diabetic wound healing and prevent scar formation.

Circulating Angiogenic Factors and Ischemic Diabetic Foot Syndrome Advancement-A Pilot Study

Despite clear evidence of inadequate angiogenesis in ischemic diabetic foot syndrome (DFS) pathogenesis, angiogenic factor level changes in patients with ischemic DFS remain inconsistent. This study aimed to assess circulating angiogenic factors concerning ischemic DFS advancement and describe their relationships with patients' clinical characteristics, microvascular parameters, and diabetic control. The study included 41 patients with ischemic DFS (67.3 (8.84) years; 82.9% males). Angiogenic processes were assessed by identifying circulating concentrations of five pro- and two anti-angiogenic factors. We found that penetrating ulcers were related to a significantly higher FGF-2 level (8.86 (5.29) vs. 5.23 (4.17) pg/mL, p = 0.02). Moreover, plasma FGF-2 showed a significant correlation with the SINBAD score (r = 0.32, p = 0.04), platelet count (r = 0.43, p < 0.01), white cell count (r = 0.42, p < 0.01), and age (r = -0.35, p = 0.03). We did not observe any significant linear relationship between the studied biomarkers and microcirculatory parameters, nor for glycemic control. In a univariate analysis using logistic regression, an increase in plasma FGF-2 was tied to greater odds of high-grade ulcers (OR 1.16; 95% CI 1.02-1.38, p = 0.043). This suggests that circulating FGF-2 may serve as a potential biomarker for predicting DFU advancement and progression. It is necessary to conduct further studies with follow-up observations to confirm this hypothesis.

Candidate SNP Markers Significantly Altering the Affinity of TATA-Binding Protein for the Promoters of Human Hub Genes for Atherogenesis, Atherosclerosis and Atheroprotection

Atherosclerosis is a systemic disease in which focal lesions in arteries promote the build-up of lipoproteins and cholesterol they are transporting. The development of atheroma (atherogenesis) narrows blood vessels, reduces the blood supply and leads to cardiovascular diseases. According to the World Health Organization (WHO), cardiovascular diseases are the leading cause of death, which has been especially boosted since the COVID-19 pandemic. There is a variety of contributors to atherosclerosis, including lifestyle factors and genetic predisposition. Antioxidant diets and recreational exercises act as atheroprotectors and can retard atherogenesis. The search for molecular markers of atherogenesis and atheroprotection for predictive, preventive and personalized medicine appears to be the most promising direction for the study of atherosclerosis. In this work, we have analyzed 1068 human genes associated with atherogenesis, atherosclerosis and atheroprotection. The hub genes regulating these processes have been found to be the most ancient. In silico analysis of all 5112 SNPs in their promoters has revealed 330 candidate SNP markers, which statistically significantly change the affinity of the TATA-binding protein (TBP) for these promoters. These molecular markers have made us confident that natural selection acts against underexpression of the hub genes for atherogenesis, atherosclerosis and atheroprotection. At the same time, upregulation of the one for atheroprotection promotes human health.

Therapeutic role of growth factors in treating diabetic wound

Wounds in diabetic patients, especially diabetic foot ulcers, are more difficult to heal compared with normal wounds and can easily deteriorate, leading to amputation. Common treatments cannot heal diabetic wounds or control their many complications. Growth factors are found to play important roles in regulating complex diabetic wound healing. Different growth factors such as transforming growth factor beta 1, insulin-like growth factor, and vascular endothelial growth factor play different roles in diabetic wound healing. This implies that a therapeutic modality modulating different growth factors to suit wound healing can significantly improve the treatment of diabetic wounds. Further, some current treatments have been shown to promote the healing of diabetic wounds by modulating specific growth factors. The purpose of this study was to discuss the role played by each growth factor in therapeutic approaches so as to stimulate further therapeutic thinking.

Mechanisms of diabetic foot ulceration: A review

Diabetic foot ulcers (DFUs) are associated with complex pathogenic factors and are considered a serious complication of diabetes. The potential mechanisms underlying DFUs have been increasingly investigated. Previous studies have focused on the three aspects of diabetic peripheral vascular disease, neuropathy, and wound infections. With advances in technology, researchers have been gradually conducting studies using immune cells, endothelial cells, keratinocytes, and fibroblasts, as they are involved in wound healing. It has been reported that the upregulation or downregulation of molecular signaling pathways is essential for the healing of DFUs. With a recent increase in the awareness of epigenetics, its regulatory role in wound healing has become a much sought-after trend in the treatment of DFUs. This review focuses on four aspects involved in the pathogenesis of DFUs: physiological and pathological mechanisms, cellular mechanisms, molecular signaling pathway mechanisms, and epigenetics. Given the challenge in the treatment of DFUs, we are hopeful that our review will provide new ideas for peers.

Effects of microRNAs on angiogenesis in diabetic wounds

Diabetes mellitus is a morbid condition affecting a growing number of the world population, and approximately one third of diabetic patients are afflicted with diabetic foot ulcers (DFU), which are chronic non-healing wounds that frequently progress to require amputation. The treatments currently used for DFU focus on reducing pressure on the wound, staving off infection, and maintaining a moist environment, but the impaired wound healing that occurs in diabetes is a constant obstacle that must be faced. Aberrant angiogenesis is a major contributor to poor wound healing in diabetes and surgical intervention is often necessary to establish peripheral blood flow necessary for healing wounds. Over recent years, microRNAs (miRNAs) have been implicated in the dysregulation of angiogenesis in multiple pathologies including diabetes. This review explores the pathways of angiogenesis that become dysregulated in diabetes, focusing on miRNAs that have been identified and the mechanisms by which they affect angiogenesis.

Wnt/β-catenin signaling activator restores hair regeneration suppressed by diabetes mellitus

Diabetes mellitus is one of the most prevalent diseases in modern society. Many complicationssuch as hepatic cirrhosis, neuropathy, cardiac infarction, and so on are associated with diabetes. Although a relationship between diabetes and hair loss has been recently reported, the treatment of diabetic hair loss by Wnt/β-catenin activators has not been achieved yet. In this study, we found that the depilation-induced anagen phase was delayed in both db/db mice and high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice. In diabetic mice, both hair regrowth and wound-induced hair follicle neogenesis (WIHN) were reduced because of suppression of Wnt/β-catenin signaling and decreased proliferation of hair follicle cells. We identified that KY19382, a small molecule that activates Wnt/β-catenin signaling, restored the capabilities of regrowth and WIHN in diabetic mice. The Wnt/β-catenin signaling activator also increased the length of the human hair follicle which was decreased under high glucose culture conditions. Overall, the diabetic condition reduced both hair regrowth and regeneration with suppression of the Wnt/β-catenin signaling pathway. Consequently, the usage of Wnt/β-catenin signaling activators could be a potential strategy to treat diabetes-induced alopecia patients. [BMB Reports 2022; 55(11): 559-564].

Wnt/β-catenin signaling activator restores hair regeneration suppressed by diabetes mellitus

Diabetes mellitus is one of the most prevalent diseases in modern society. Many complicationssuch as hepatic cirrhosis, neuropathy, cardiac infarction, and so on are associated with diabetes. Although a relationship between diabetes and hair loss has been recently reported, the treatment of diabetic hair loss by Wnt/β-catenin activators has not been achieved yet. In this study, we found that the depilation-induced anagen phase was delayed in both db/db mice and high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice. In diabetic mice, both hair regrowth and wound-induced hair follicle neogenesis (WIHN) were reduced because of suppression of Wnt/β-catenin signaling and decreased proliferation of hair follicle cells. We identified that KY19382, a small molecule that activates Wnt/β-catenin signaling, restored the capabilities of regrowth and WIHN in diabetic mice. The Wnt/β-catenin signaling activator also increased the length of the human hair follicle which was decreased under high glucose culture conditions. Overall, the diabetic condition reduced both hair regrowth and regeneration with suppression of the Wnt/β-catenin signaling pathway. Consequently, the usage of Wnt/β-catenin signaling activators could be a potential strategy to treat diabetes-induced alopecia patients. [BMB Reports 2022; 55(11): 559-564].

Wound Healing Impairment in Type 2 Diabetes Model of Leptin-Deficient Mice—A Mechanistic Systematic Review

Type II diabetes mellitus (T2DM) is one of the most prevalent diseases in the world, associated with diabetic foot ulcers and impaired wound healing. There is an ongoing need for interventions effective in treating these two problems. Pre-clinical studies in this field rely on adequate animal models. However, producing such a model is near-impossible given the complex and multifactorial pathogenesis of T2DM. A leptin-deficient murine model was developed in 1959 and relies on either dysfunctional leptin (ob/ob) or a leptin receptor (db/db). Though monogenic, this model has been used in hundreds of studies, including diabetic wound healing research. In this study, we systematically summarize data from over one hundred studies, which described the mechanisms underlying wound healing impairment in this model. We briefly review the wound healing dynamics, growth factors’ dysregulation, angiogenesis, inflammation, the function of leptin and insulin, the role of advanced glycation end-products, extracellular matrix abnormalities, stem cells’ dysregulation, and the role of non-coding RNAs. Some studies investigated novel chronic diabetes wound models, based on a leptin-deficient murine model, which was also described. We also discussed the interventions studied in vivo, which passed into human clinical trials. It is our hope that this review will help plan future research.

Synergistic effect of glucagon-like peptide-1 analogue liraglutide and ZnO on the antibacterial, hemostatic, and wound healing properties of nanofibrous dressings

Bacterial infections and poor vascularization delay wound healing, thus necessitating alternative strategies for functional wound dressings. Zinc oxide (ZnO) has been shown to exert a potent antibacterial effect against bacterial species. Similarly, Glucagon-like peptide-1 (GLP-1) analogue liraglutide (LG) has been shown to promote vascularization and improve wound healing. The objective of this research was to investigate the synergistic effect of ZnO nanoparticles (ZnO-NPs) and LG to simultaneously induce antibacterial, hemostatic, and vascularization effects for infected wound healing. Electrospun poly (l-lactide-co-glycolide)/gelatin (PLGA/Gel) membranes containing ZnO-NPs and LG displayed good biocompatibility and hemostatic ability. Both, ZnO-NPs and LG exhibited synergistic antibacterial effect against Staphylococcus aureus and Escherichia coli as well as improved the migration and tubule-like network formation of human umbilical vein endothelial cells (HUVECs) in vitro. Once evaluated in a bacterial-infected wound model in rats, the membranes loaded with ZnO-NPs and LG effectively promoted wound healing causing significant reduction in wound area and scar-like tissue formation. Therefore, ZnO-NPs/LG synergism may offer an invaluable solution for the treatment of poorly healing infected wounds.

Pigment epithelium-derived factor maintains tight junction stability after myocardial infarction in rats through inhibition of the Wnt/β-catenin signaling pathway

PURPOSE

The impairment of the coronary microcirculatory barrier caused by acute myocardial infarction (AMI) is closely related to poor prognosis. Recently, pigment epithelial-derived factor (PEDF) has been proven to be a promising cardiovascular protective drug. In this study, we demonstrated the protective role of PEDF in endothelial tight junctions (TJs) and the vascular barrier in AMI.

MATERIALS AND METHODS

2, 3, 5-triphenyltetrazolium chloride (TTC), echocardiography and immunofluorescence staining were used to observe the size of infarcted myocardium area and cardiac function in myocardial tissue, and the distribution of tight junction proteins in human coronary endothelial cells (HCAEC). Dextran leakage assay and Transwell were used to assess the extent of vascular and HCAEC leakage. PCR and Western blot were used to detect tight junction-related mRNA and protein, and signaling pathway protein expression.

RESULTS

PEDF effectively reduced the infarction area and improved cardiac function in AMI rats, and lowered the leakage in AMI rats' angiocarpy and oxygen-glucose deprivation (OGD)-treated HCAEC. Furthermore, PEDF upregulated the expression of TJ mRNA and proteins in vivo and vitro. Mechanistically, PEDF inhibited the expression of phosphorylated low-density lipoprotein receptor-related protein 6 (p-LRP6) and active β-catenin under OGD, thus suppressing the activation of the classical Wnt pathway.

CONCLUSIONS

These novel findings demonstrated that PEDF maintained the expression of TJ proteins and endothelial barrier integrity by inhibiting the classical Wnt pathway during AMI.

YB-1 Recruits Drosha to Promote Splicing of pri-miR-192 to Mediate the Proangiogenic Effects of H2S

Aims: The genes targeted by miRNAs have been well studied. However, little is known about the feedback mechanisms to control the biosynthesis of miRNAs that are essential for the miRNA feedback networks in the cells. In this present study, we aimed at examining how hydrogen sulfide (H₂S) promotes angiogenesis by regulating miR-192 biosynthesis. Results: H₂S promoted in vitro angiogenesis and angiogenesis in Matrigel plugs embedded in mice by upregulating miR-192. Knockdown of the H₂S-generating enzyme cystathionine γ-lyase (CSE) suppressed in vitro angiogenesis, and this suppression was rescued by exogenous H₂S donor NaHS. Plakophilin 4 (PKP4) served as a target gene of miR-192. H₂S up-regulated miR-192 via the VEGFR2/Akt pathway to promote the splicing of primary miR-192 (pri-miR-192), and it resulted in an increase in both the precursor- and mature forms of miR-192. H₂S translocated YB-1 into the nuclei to recruit Drosha to bind with pri-miR-192 and promoted its splicing. NaHS treatment promoted angiogenesis in the hindlimb ischemia mouse model and the skin-wound-healing model in diabetic mice, with upregulated miR-192 and downregulated PKP4 on NaHS treatment. In human atherosclerotic plaques, miR-192 levels were positively correlated with the plasma H₂S concentrations. Innovation and Conclusion: Our data reveal a role of YB-1 in recruiting Drosha to splice pri-miR-192 to mediate the proangiogenic effect of H₂S. CSE/H₂S/YB-1/Drosha/miR-192 is a potential therapeutic target pathway for treating diseases, including organ ischemia and diabetic complications. Antioxid. Redox Signal. 36, 760-783. The Clinical Trial Registration number is 2016-224.

Approaches for Regenerative Healing of Cutaneous Wound with an Emphasis on Strategies Activating the Wnt/β-Catenin Pathway

Significance: In adult mammals, spontaneous repair of a cutaneous wound occurs slowly and leaves a scar with skin adnexa deficiencies. To accelerate cutaneous wound-healing rates and avoid scar formation, current studies have focused on regenerative therapies. Recent Advances: Emerging therapeutics for regenerative wound healing often focus on the use of growth factors and stem cells. However, these therapeutic approaches have limited routine clinical use due to high costs and technical requirements. Critical Issue: Understanding the molecular mechanisms involved in the signaling pathways for cutaneous wound healing and neogenic synthesis of the skin components is important for identification of novel targets for the development of regenerative wound-healing agents. Future Directions: The Wnt/β-catenin pathway is a well-known key player for enhancement of the overall healing process involving tissue regeneration via crosstalk with other signaling pathways. Strategies that activate the Wnt/β-catenin pathway via modulation of the pathway-controlling regulatory factors could provide effective therapeutic approaches for regenerative wound healing.

Interleukin-25-Mediated-IL-17RB Upregulation Promotes Cutaneous Wound Healing in Diabetic Mice by Improving Endothelial Cell Functions

Diabetic foot ulcer (DFU) frequently leads to non-traumatic amputation and finally even death. However, the mechanism of DFU is not fully understood. Interleukin 25 (IL-25), an alarmin cytokine that responds to tissue injury, has been reported to participate in tissue regeneration and maintaining glucose homeostasis. However, the role of IL-25 in diabetic wound healing remains unknown. Here, we showed that interleukin 17 receptor B (IL-17RB), the functional receptor of IL-25, was significantly inhibited in the wound skin of both diabetic patients with DFU and streptozotocin (STZ)-induced diabetic mice. Topical administration of recombinant IL-25 protein improved angiogenesis and collagen deposition in the wound bed and thus ameliorated delayed diabetic wound healing. IL-25 increased endothelial-specific CD31 expression in diabetic wounds and exogenous IL-25 protected endothelial cells from high glucose-impaired cell migration and tube formation in vitro. We further revealed that IL-25-mediated-IL-17RB signaling rescued the downregulation of Wnt/β-catenin pathway both in vivo in diabetic mice and in vitro in HUVECs and induced the phosphorylation of AKT and ERK 1/2 in HUVECs under high glucose conditions. This study defines a positive regulatory role of IL-25-mediated-IL-17RB signaling in diabetic wound healing and suggests that induction of IL-25-mediated-IL-17RB signaling may be a novel therapeutic strategy for treating poor healing diabetic wounds.

Notoginsenoside R1 Facilitated Wound Healing in High-Fat Diet/Streptozotocin-Induced Diabetic Rats

Diabetic ulcers bring about high morbidity and mortality in patients and cause a great economic burden to society as a whole. Since existing treatments cannot fulfil patient requirements, it is urgent to find effective therapies. In this study, the wound healing effect of topical notoginsenoside R1 (NR1) treatment on diabetic full-thickness wounds in type II diabetes mellitus (T2DM) was induced by the combination of a high-fat diet and streptozotocin (STZ) injection. NR1 significantly increased the wound closure rate, enhanced extracellular matrix (ECM) secretion, promoted collagen growth, increased platelet endothelial cell adhesion molecule-1 (CD31) expression, and decreased cleaved caspase-3 expression. RNA-Seq analysis identified ECM remodeling and inflammation as critical biological processes and Timp1 and Mmp3 as important targets in NR1-mediated wound healing. Further experiments showed that NR1-treated wounds demonstrated higher expression of tissue inhibitor of metalloproteinase 1 (TIMP1) and transforming growth factor-β1 (TGFβ1) and lower expression of matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 3 (MMP3), interleukin-1β (IL-1β), and interleukin-6 (IL-6) than diabetic wounds. These investigations promote the understanding of the mechanism of NR1-mediated diabetic wound healing and provide a promising therapeutic drug to enhance diabetic wound healing.

Pro- and Anti-Angiogenic Factors: Their Relevance in Diabetic Foot Syndrome-A Review

Peripheral arterial disease can involve tissue loss in up to 50% of patients with diabetic foot syndrome (DFS). Consequently, revascularization of narrowed or occluded arteries is one of the most common forms of comprehensive treatment. However, technically successful angioplasty does not always result in the healing of ulcers. The pathomechanism of this phenomenon is still not fully understood, but inadequate angiogenesis in tissue repair may play an essential role. Changes in pro- and anti-angiogenic factors among patients with DFS are not always clear and conclusive. In particular, some studies underline the role of decreased concentration of pro-angiogenic factors and higher levels of anti-angiogenic mediators. Nevertheless, there are still controversial issues, including the paradox of impaired wound healing despite high concentrations of some pro-angiogenic factors, dynamics of their expression during the healing process, and their mutual relationships. Exploring this process among diabetic patients may provide new insight into well-known methods of treatment and show their real benefits and chances for improving outcomes.

The Anti-inflammatory and Proangiogenic Properties of High-Density Lipoproteins: An Emerging Role in Diabetic Wound Healing

Significance: Prolonged inflammation and impaired angiogenesis are the two principal factors that prevent successful wound healing, which is exacerbated in people with diabetes. There is a significant need for new wound healing treatments that target both these factors simultaneously. This review discusses the emerging evidence that high-density lipoproteins (HDL) have pleiotropic wound healing benefits. Recent Advances: Numerous in vitro and in vivo studies have demonstrated the anti-inflammatory and proangiogenic effects of HDL. In endothelial cells, HDL mediate these effects through interaction with the scavenger receptor SR-BI, which activates the PI3K/Akt pathway, causing a decrease in inflammatory protein production and an increase in proangiogenic growth factors. In macrophages, HDL inhibit inflammation through suppression of the nuclear factor kappa B activation pathway. This review details the molecular disturbances that cause impaired wound healing in diabetes with a particular focus on inflammation and angiogenesis and the pathways in which HDL provide benefit. Critical Issues: Diabetic foot ulcers (DFUs) impose a major public health challenge worldwide. It is estimated that 20% patients with DFUs require amputation, which is accompanied by a significant social and economic burden. To date, there are no therapeutic agents with pleiotropic effects that actively improve wound healing, highlighting a therapeutic void for this complex disease.

Diabetic wound healing: The impact of diabetes on myofibroblast activity and its potential therapeutic treatments

Diabetes is a systemic disease in which the body cannot regulate the amount of sugar, namely glucose, in the blood. High glucose toxicity has been implicated in the dysfunction of diabetic wound healing, following insufficient production (Type 1) or inadequate usage (Type 2) of insulin. Chronic non-healing diabetic wounds are one of the major complications of both types of diabetes, which are serious concerns for public health and can impact the life quality of patients significantly. In general, diabetic wounds are characterized by deficient chemokine production, an unusual inflammatory response, lack of angiogenesis and epithelialization, and dysfunction of fibroblasts. Increasing scientific evidence from available experimental studies on animal and cell models strongly associates impaired wound healing in diabetes with dysregulated fibroblast differentiation to myofibroblasts, interrupted myofibroblast activity, and inadequate extracellular matrix production. Myofibroblasts play an important role in tissue repair by producing and organizing extracellular matrix and subsequently promoting wound contraction. Based on these studies, hyperglycaemic conditions can interfere with cytokine signalling pathways (such as growth factor-β pathway) affecting fibroblast differentiation, alter fibroblast apoptosis, dysregulate dermal lipolysis, and enhance hypoxia damage, thus leading to damaged microenvironment for myofibroblast formation, inappropriate extracellular matrix modulation, and weakened wound contraction. In this review, we will focus on the current available studies on the impact of diabetes on fibroblast differentiation and myofibroblast function, as well as potential treatments related to the affected pathways.

A small molecule HIF-1α stabilizer that accelerates diabetic wound healing

Impaired wound healing and ulcer complications are a leading cause of death in diabetic patients. In this study, we report the design and synthesis of a cyclometalated iridium(III) metal complex 1a as a stabilizer of hypoxia-inducible factor-1α (HIF-1α). In vitro biophysical and cellular analyses demonstrate that this compound binds to Von Hippel-Lindau (VHL) and inhibits the VHL-HIF-1α interaction. Furthermore, the compound accumulates HIF-1α levels in cellulo and activates HIF-1α mediated gene expression, including VEGF, GLUT1, and EPO. In in vivo mouse models, the compound significantly accelerates wound closure in both normal and diabetic mice, with a greater effect being observed in the diabetic group. We also demonstrate that HIF-1α driven genes related to wound healing (i.e. HSP-90, VEGFR-1, SDF-1, SCF, and Tie-2) are increased in the wound tissue of 1a-treated diabetic mice (including, db/db, HFD/STZ and STZ models). Our study demonstrates a small molecule stabilizer of HIF-1α as a promising therapeutic agent for wound healing, and, more importantly, validates the feasibility of treating diabetic wounds by blocking the VHL and HIF-1α interaction.

Predictors of wound leakage in patients undergoing surgery for neck of femur fractures

AIMS

Persistent wound leakage following joint arthroplasty is a known risk for periprosthetic joint infection. Little is known of the predictors of wound leakage, particularly in patients with a fractured neck of femur. We aimed to determine patient and surgical risk factors for wound leakage in this cohort.

MATERIALS AND METHODS

All patients undergoing surgery for a fractured neck of femur at Leicester Royal Infirmary between May and August 2017 were included. Patients were identified from a prospective database and placed into two groups: those with wound leakage later than three days postoperatively and those without leakage. All previously reported potential risk factors for wound leakage were compared between groups using a chi-square test and logistic regression. A Kattan-style nomogram was also created to allow probabilities output for the regression predictive models in a visual representation.

RESULTS

Two hundred patients underwent surgery for a fractured neck of femur. Overall, 17% of patients (33/200) developed a persistent leaky wound. A multivariable model highlighted increased age (p = 0.01), raised body mass index (BMI; > 25 kg/m²; p = 0.047), diabetes (p = 0.03) and intramedullary hip screw fixation (p = 0.03) as significant risk factors for wound leakage. Patients with persistent wound leakage had significantly longer hospital admission than those without (p = 0.001).

DISCUSSION

Our analysis identified four perioperative risk factors for wound leakage following fractured neck of femur surgery. We also developed a novel tool to identify those patients at highest risk of leakage. Once identified, the aggressive management of certain medical comorbidities in these patients may help to reduce their incidence of wound issues and the prolonged admissions that result.

Beyond the NFAT Horizon: From Cyclosporine A-Induced Adverse Skin Effects to Novel Therapeutics

The immunophilin ligand, cyclosporine A (CsA), which inhibits nuclear factor of activated T cells (NFAT) activity, is a cornerstone of immunosuppressive therapy. Yet, the molecular basis of its prominent, nonimmunosuppression-related adverse skin effects, namely drug-induced excessive hair growth (hypertrichosis), is insufficiently understood. Here, we argue that analysis of these adverse effects can uncover clinically important, previously unknown mechanisms of CsA and identify new molecular targets and lead compounds for therapeutic intervention. We exemplify this through our recent discovery that CsA suppresses the potent Wnt inhibitor, secreted frizzled related protein (SFRP)1, in human hair follicles, thereby promoting hair growth and causing hypertrichosis. On this basis, we advocate a new focus on deciphering the molecular basis of the adverse effects of CsA in suitable human model systems as a lead to developing novel therapeutics.

SDF-1α Gene-Activated Collagen Scaffold Restores Pro-Angiogenic Wound Healing Features in Human Diabetic Adipose-Derived Stem Cells

Non-healing diabetic foot ulcers (DFUs) can lead to leg amputation in diabetic patients. Autologous stem cell therapy holds some potential to solve this problem; however, diabetic stem cells are relatively dysfunctional and restrictive in their wound healing abilities. This study sought to explore if a novel collagen-chondroitin sulfate (coll-CS) scaffold, functionalized with polyplex nanoparticles carrying the gene encoding for stromal-derived factor-1 alpha (SDF-1α gene-activated scaffold), can enhance the regenerative functionality of human diabetic adipose-derived stem cells (ADSCs). We assessed the impact of the gene-activated scaffold on diabetic ADSCs by comparing their response against healthy ADSCs cultured on a gene-free scaffold over two weeks. Overall, we found that the gene-activated scaffold could restore the pro-angiogenic regenerative response in the human diabetic ADSCs similar to the healthy ADSCs on the gene-free scaffold. Gene and protein expression analysis revealed that the gene-activated scaffold induced the overexpression of SDF-1α in diabetic ADSCs and engaged the receptor CXCR7, causing downstream β-arrestin signaling, as effectively as the transfected healthy ADSCs. The transfected diabetic ADSCs also exhibited pro-wound healing features characterized by active matrix remodeling of the provisional fibronectin matrix and basement membrane protein collagen IV. The gene-activated scaffold also induced a controlled pro-healing response in the healthy ADSCs by disabling early developmental factors signaling while promoting the expression of tissue remodeling components. Conclusively, we show that the SDF-1α gene-activated scaffold can overcome the deficiencies associated with diabetic ADSCs, paving the way for autologous stem cell therapies combined with novel biomaterials to treat DFUs.

Advances of hydrogel dressings in diabetic wounds

The hydrogel dressings with various functions for diabetic wound treatment.

Anti-Ageing Protein β-Klotho Rejuvenates Diabetic Stem Cells for Improved Gene-Activated Scaffold Based Wound Healing

Skin wounds can lead to serious morbidity complications in diabetic patients due to the reduced healing potential of autologous stem cells. One reason for the low functional potency of stem cells from diabetic patients (diabetic stem cells) is attributed to their senescent-like nature. Here, we investigated if an anti-ageing protein, β-klotho, could be used to rejuvenate diabetic stem cells and to promote pro-angiogenic gene-activated scaffold (GAS)-induced functional response for wound healing applications. Human stem cells derived from the adipose tissue (adipose-derived stem cells (ADSCs)) of normal and diabetic (type 2) donors were used for the study. We report that the β-klotho priming facilitated inflammatory signal pruning by reducing interleukin-8 release by more than half while concurrently doubling the release of monocyte chemoattractant protein-1. Additionally, β-klotho priming enhanced the pro-angiogenic response of diabetic ADSCs on GAS by dampening the release of anti-angiogenic factors (i.e., pigment epithelium-derived factor, tissue inhibitor of metalloproteinase-1 and thrombospondin-1) while simultaneously supporting the expression of pro-angiogenic factors (i.e., Vascular Endothelial Growth Factor (VEGF), angiopoietin-2 and angiogenin). Finally, we show that β-klotho pre-treatment expedites the cellular expression of matrix proteins such as collagen IV and collagen VI, which are implicated in tissue maturation. Taken together, our study provides evidence that the synergistic effect of the pro-angiogenic GAS and β-klotho activation effectively accelerates the functional development of diabetic ADSCs for wound healing applications.

Cryptotanshinone enhances wound healing in type 2 diabetes with modulatory effects on inflammation, angiogenesis and extracellular matrix remodelling

CONTEXT

Cryptotanshinone (CT) is a diterpene quinone compound from Salvia miltiorrhiza Bge. Labiatae has been widely used in cardio-cerebral vascular diseases, which could be potentially effective in treating diabetic wounds.

OBJECTIVE

This study evaluates the wound healing activity of CT by employing an excisional wound splinting model in db/db mice.

MATERIALS AND METHODS

Wounds were induced at the dorsum of non-diabetic (db/+) and diabetic (db/db) mice and treated with sodium carboxymethyl cellulose (CMC-Na) or 300 mg/kg/d CT for 16 days. Wound closure was measured every two days. Body weight, fasting blood glucose, re-epithelialization, granulation, leukocyte infiltration, capillary density, collagen deposition and expressions of CXCL1, CXCL2, VEGF, Ang-1, p-eNOS, eNOS, α-SMA, MMP2 and MMP9 were analysed. Expression of VEGF and tube formation was measured in vitro with human umbilical vein endothelial cells (HUVECs).

RESULTS

CT significantly accelerated rate of wound closure, as the contraction ratio increased from 68% (non-treated group) to 83% (CT-treated group) at days 16 post-injury. A significant increase was observed in re-epithelialization and granulation tissue formation. Mechanistically, CT suppressed leukocyte infiltration and CXCL1 and CXCL2 expression. CT treatment also increased blood vessel density and expression level of VEGF, Ang-1 and p-eNOS. In vitro, CT boosted expression of VEGF and tube formation of endothelial cells. Moreover, extracellular matrix (ECM) remodelling was enhanced by CT via promoting fibroblast transformation and inhibiting MMP2 and MMP9.

CONCLUSIONS

Our study provides evidence that CT could be developed as a potential therapeutic agent for the treatment of chronic diabetic wound healing.

Curcumin Therapeutic Modulation of the Wnt Signaling Pathway

Curcumin, isolated from the rhizome of Curcuma longa, is one of the most extensively studied phytochemicals. This natural compound has a variety of pharmacological effects including antioxidant, anti-inflammatory, anti-tumor, cardio-protective, hepato-protective and anti-diabetic. Wnt signaling pathway, one of the potential targets of curcumin through upregulation and/or downregulation, plays a significant role in many diseases, even in embryogenesis and development of various organs and systems. In order to exert an anti-tumor activity in the organism, curcumin seems to inhibit the Wnt pathway. The downstream mediators of Wnt signaling pathway such as c-Myc and cyclin D1 are also modified by curcumin. This review demonstrates how curcumin influences the Wnt signaling pathway and is beneficial for the treatment of neurological disorders (Alzheimer's and Parkinson's diseases), cancers (melanoma, lung cancer, breast cancer, colon cancer, endothelial carcinoma, gastric carcinoma and hepatocellular carcinoma) and other diseases, such as diabetes mellitus or bone disorders.

Elevated pigment epithelium-derived factor induces diabetic erectile dysfunction via interruption of the Akt/Hsp90β/eNOS complex

AIMS/HYPOTHESIS

Diabetes mellitus erectile dysfunction (DMED) is a common complication of diabetes. The level of pigment epithelium-derived factor (PEDF) is significantly upregulated in the serum of individuals with obesity and diabetes. However, whether elevated PEDF levels contribute to DMED remains unknown. This study aimed to investigate the pathogenic role of PEDF and its related mechanism in DMED.

METHODS

We enrolled 65 men, of whom 20 were nondiabetic control participants, 21 participants with diabetes but without erectile dysfunction, and 24 with DMED. The International Index of Erectile Function (IIEF-5) questionnaire was administered to evaluate erectile function. Plasma PEDF in diabetic participants and streptozotocin (STZ)-induced diabetic animals was detected by ELISA. Erectile function was evaluated by measuring the intracavernous pressure (ICP) and the ICP/mean arterial pressure (MAP) ratio in STZ-induced diabetic rats treated with PEDF-neutralising antibody (PEDF-Ab), db/db mice treated with PEDF-Ab, and Pedf knockout mice with STZ-induced diabetes. The overexpression of PEDF was implemented by intraperitoneal injection of recombinant PEDF and intracavernous injection of PEDF-expressing adenovirus. A mechanistic study was performed by immunofluorescence staining, bimolecular fluorescence complementation (BiFC), immunoprecipitation and western blotting.

RESULTS

We found that the plasma level of PEDF was significantly higher in participants with DMED compared with diabetic counterparts without erectile dysfunction and nondiabetic controls. Interestingly, PEDF levels were negatively correlated with plasma nitrite/nitrate levels and erectile function in DMED patients and STZ-induced diabetic rats. Furthermore, overexpression of PEDF significantly suppressed ICP and endothelial nitric oxide synthase (eNOS) phosphorylation in control rats. In contrast, the PEDF-Ab and Pedf knockout ameliorated ICP and eNOS phosphorylation in diabetic rats and mice. Mechanistically, PEDF promoted the membrane translocation of Hsp90β and directly bound to the amino acid residues 341-724 of Hsp90β on the endothelial cell surface, subsequently blocking intracellular Hsp90β/Akt/eNOS complex formation and downregulating eNOS phosphorylation.

CONCLUSIONS/INTERPRETATION

These results indicate that elevated PEDF levels contribute to impaired erectile function by suppressing Hsp90β-mediated eNOS phosphorylation and that PEDF may represent a novel therapeutic target for diabetic erectile dysfunction. Graphical abstract.

Potential role of hydrogen sulfide in diabetes-impaired angiogenesis and ischemic tissue repair

Diabetes is one of the most prevalent metabolic disorders and is estimated to affect 400 million of 4.4% of population worldwide in the next 20 year. In diabetes, risk to develop vascular diseases is two-to four-fold increased. Ischemic tissue injury, such as refractory wounds and critical ischemic limb (CLI) are major ischemic vascular complications in diabetic patients where oxygen supplement is insufficient due to impaired angiogenesis/neovascularization. In spite of intensive studies, the underlying mechanisms of diabetes-impaired ischemic tissue injury remain incompletely understood. Hydrogen sulfide (H₂S) has been considered as a third gasotransmitter regulating angiogenesis under physiological and ischemic conditions. Here, the underlying mechanisms of insufficient H₂S-impaired angiogenesis and ischemic tissue repair in diabetes are discussed. We will primarily focuses on the signaling pathways of H₂S in controlling endothelial function/biology, angiogenesis and ischemic tissue repair in diabetic animal models. We summarized that H₂S plays an important role in maintaining endothelial function/biology and angiogenic property in diabetes. We demonstrated that exogenous H₂S may be a theraputic agent for endothelial dysfunction and impaired ischemic tissue repair in diabetes.

Integrated analysis of circRNA-miRNA-mRNA regulatory network identifies potential diagnostic biomarkers in diabetic foot ulcer

Diabetic foot ulcer (DFU) is a common and serious complication of diabetes mellitus, which influences patients’ quality of life. Recently, circRNA regulated the mRNA levels by functioning as miRNA sponge in various disease, including diabetes mellitus. Nevertheless, the circRNA-miRNA-mRNA regulatory network involved in DFU remains obscure. The aim of this study is to construct a competing endogenous RNA (ceRNA) network and screen biological indicators as diagnostic factors in DFU.

All the differentially expressed circRNAs, miRNAs and mRNAs were derived from Gene Expression Omnibus database. Furthermore, circRNAs identified by cytoHubba analysis and miRNAs obtained by human miRNA-disease database were used to construct DFU-specific ceRNA network with intersection of mRNAs. Functional enrichment analysis displayed the function and pathway of dysregulated mRNAs. Hub genes with high diagnostic value were screened by ClusterONE, GO semantic similarity and receiver operating characteristic (ROC) curve.

Here, the ceRNA network consisted of 8 circRNAs, 11 miRNAs and 91 mRNAs. Functional enrichment analysis demonstrated diabetic complications-related pathway including TGF-beta, FoxO and Wnt signaling pathway. GO semantic similarity and ROC curve analysis showed 6 hub genes with high diagnostic value (the area under the ROC curve ≥ 0.8) in patients with DFU, including BCL2, CCND1, IRAK4, SMAD4, SP1 and SUFU, which were identified as potential target genes for DFU diagnosis. In conclusion, the present study looked at a circRNA-miRNA-mRNA regulatory network with DFU and screened the potential function of mRNA, then identified novel diagnostic biomarkers and therapeutic targets for patients with DFU.

Dysregulation of microRNA expression in diabetic skin

BACKGROUND

Clinical skin manifestations are common in diabetes; however, molecular mechanisms underlying such defects are largely unknown. Several findings indicate a role for microRNAs (miRNAs) in skin homeostasis.

OBJECTIVE

To investigate whether miRNA expression is altered in diabetic skin.

METHODS

Type 1 and 2 mouse models of diabetes were used. MiRNA profiling was performed on RNA extracted from the skin of type 1 diabetic mice and non-diabetic controls. Expression levels of pri-miRNAs and of miRNA-biogenesis genes were also analyzed. Biogenesis gene expression analysis was performed in human dermal fibroblasts cultured in hyperglycemic, hypoxic or oxidative stress conditions.

RESULTS

Several miRNAs were differentially expressed in diabetic skin with a general down-modulation as compared to controls. Bioinformatics analysis of signature-miRNA target genes showed the enrichment in pathways involved in skin homeostasis, such as TGF-β and Wnt. MiRNA alteration in diabetic skin associated with reduced expression levels of DROSHA, DGCR8, XPO5, DICER1, AGO2, both as mRNA and protein. Reduced biogenesis gene expression did not correlate with accumulation of pri-miRNAs, which displayed differences in expression levels similar to those found for their mature miRNAs. Experiments with cultured fibroblasts showed that hypoxia and oxidative stress induced the down-regulation of miRNA-biogenesis genes in this skin cell type.

CONCLUSION

A general down-regulation of differentially expressed miRNAs was found in diabetic skin. This alteration is part of and is dependent from a wider transcriptional defect also affecting the expression of pri-miRNAs and of genes responsible for miRNA biogenesis. Such an alteration is likely contributing to diabetic skin manifestations.

Expression Pattern of Plexin Domain Containing 2 in Human Hepatocellular Carcinoma

Plexin domain containing 2 (PLXDC2) is expressed in endothelial cells of tumor stroma, neural progenitor cells, and pluripotent stem cells, but their respective tissue expression pattern is not fully understood. In this study, we investigated the expression pattern of PLXDC2 in human hepatocellular carcinoma (HCC) tissues using a highly specific anti-PLXDC2 rabbit monoclonal antibody, which was recently developed. PLXDC2 was expressed in human HCC tissues including HCC cells, tumor vascular endothelial cells, and some infiltrating cells. The developed anti-PLXDC2 antibody allowed for highly specific and low background staining. Based on these current findings of PLXDC2 expression in human HCC tissues, the window may now be open to explore the role of PLXDC2 in human HCC.

Pigment epithelium-derived factor alleviates depressive-like behaviors in mice by modulating adult hippocampal synaptic growth and Wnt pathway

Pigment epithelium-derived factor (PEDF, also known as SERPINF1) is a secreted glycoprotein with neuroprotective effects. However, the potential role of PEDF in major depressive disorder (MDD) remains largely unknown. Here, applying two-dimensional gel electrophoresis (2-DE) proteomics, we found that PEDF levels were significantly decreased in the plasma of 12 first-episode treatment-naïve MDD patients (FETND) compared to the levels in 12 healthy controls (HCs). PEDF levels were especially lower in MDD patients than in HCs and patients with bipolar disorder (BD) and schizophrenia (SCZ), and elevated PEDF were consistent with decreased HAM-D scores in patients given antidepressant therapy (ADT). Animal research indicated that PEDF was decreased in the periphery and hippocampus of two well-known depression rodent models (the chronic unpredictable mild stress (CUMS) rat model and chronic social defeat stress (CSDS) mouse model). Decreased PEDF levels in the hippocampus led to depressive-like behaviors, synaptic impairments and aberrant Wnt signaling in C57BL mice, while increased PEDF resulted in the opposite results. Mechanistic studies indicated that PEDF contributes to dendritic growth and Wnt signaling activation in the hippocampus of adult mice. Taken together, the results of our study demonstrate the involvement of PEDF and its related mechanism in depression, thus providing translational evidence suggesting that PEDF may be a novel therapeutic target for depression.

Vitamin D (1,25-(OH)2D3) regulates the gene expression through competing endogenous RNAs networks in high glucose-treated endothelial progenitor cells

Vitamin D (vit-D) supplementation can improve endothelial cell function in type 2 diabetes mellitus patients with vit-D insufficiency or deficiency. In the present study, we aimed to compare the expression profiles of circRNAs, lncRNAs, miRNAs, and mRNAs between 1,25-(OH)₂D₃-treated endothelial progenitor cells (EPCs) and control cells, and to further construct the 1,25-(OH)₂D₃-regulated ceRNA networks in EPCs. RNA sequencing was performed on the 1,25-(OH)₂D₃-treated EPCs and control cells derived from the bone marrow (BM). Bioinformatics analyses were performed to identify differentially expressed (DE) microRNAs (miRNAs), circular RNAs (circRNAs), mRNAs, and long non-coding RNAs (lncRNAs). Then Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to predict the function of genes. Competing endogenous RNA (ceRNA) networks were constructed with Cytoscape software. 1,25-(OH)₂D₃ application induced changes in the expression profiles of 1791 mRNAs, 2726 lncRNAs, 205 circRNAs, and 45 miRNAs in EPCs treated with high levels of glucose. These DE RNAs were associated with MMP and GTPase activities, specific signaling pathways, and components of actin, extracellular matrix, or adherens junction. DE circRNAs, which functioned independently of their linear host genes, interacted with miRNAs to serve as miRNA sponges in complex ceRNA networks. The data indicated that circRNAs and lncRNAs comprised ceRNAs to sponge effects of miRNAs on the expressions of mRNAs following 1,25-(OH)₂D₃ application in EPCs. 1,25-(OH)₂D₃ improved the function of EPCs via associated ceRNA interaction networks in diabetes patients.

Canonical Wnt Signaling Promotes Neovascularization Through Determination of Endothelial Progenitor Cell Fate via Metabolic Profile Regulation

Endothelial progenitor cells (EPCs) contribute to blood vessel formation. Canonical Wnt signaling plays an important role in physiological and pathological angiogenesis and EPC fate regulation. However, the mechanism for Wnt signaling to regulate EPC fate in neovascularization (NV) has not been clearly defined. Here, we showed that very low-density lipoprotein receptor knockout (Vldlr ^-/- ) mice, a model of ocular NV induced by Wnt signaling overactivation, have increased EPC numbers in the bone marrow, blood, and retina, as well as an elevated mitochondrial membrane potential indicating higher mitochondrial function of EPCs in the circulation. Isolated EPCs from Vldlr ^-/- mice showed overactivated Wnt signaling, correlating with increased mitochondrial function, mass, and DNA copy numbers, compared with WT EPCs. Our results also demonstrated that Wnt signaling upregulated mitochondrial biogenesis and function, while inhibiting glycolysis in EPCs, which further decreased EPC stemness and promoted EPCs to a more active state toward differentiation, which may contribute to pathologic vascular formation. Fenofibric acid, an active metabolite of fenofibrate, inhibited Wnt signaling and mitochondrial function in EPCs and decreased EPC numbers in Vldlr ^-/- mice. It also decreased mitochondrial biogenesis and reactive oxygen species production in Vldlr ^-/- EPCs, which may be responsible for its therapeutic effect on diabetic retinopathy. These findings demonstrated that Wnt signaling regulates EPC fate through metabolism, suggesting potential application of the EPC metabolic profile as predictor and therapeutic target for neovascular diseases. Stem Cells 2019;37:1331-1343.

Elevated Kallikrein-binding protein in diabetes impairs wound healing through inducing macrophage M1 polarization

Background

The accumulation of M1-polarized macrophages and excessive inflammation are important in the pathogenesis of diabetic foot ulcer (DFU). However, the underlying mechanism of DFU pathogenesis and the crucial regulators of DFU are less well known. Our previous study reported that kallikrein-binding protein (KBP), an angiogenesis inhibitor, was significantly upregulated in diabetic patients compared to its levels in controls. The effects of KBP on monocyte chemotaxis and macrophage M1 polarization were elucidated in this study.

Methods

Plasma KBP levels and monocyte counts were assessed by ELISA and flow cytometry. Wound closure rates in different groups were monitored daily. The phenotype and recruitment of macrophages were measured by real-time PCR, western blot and immunofluorescence assays. The expression of Notch and NF-κB signalling pathway members was determined by the methods mentioned above. ChIP and dual-luciferase reporter gene assays were employed to explore the binding and transcriptional regulation of Hes1 and iNOS.

Results

We found that plasma KBP levels and circulating monocytes were elevated in diabetic patients compared to those in nondiabetic controls, and both were higher in diabetic patients with DFU than in diabetic patients without DFU. KBP delayed wound healing in normal mice; correspondingly, KBP-neutralizing antibody ameliorated delayed wound healing in diabetic mice. Circulating monocytes and macrophage infiltration in the wound were upregulated in KBP-TG mice compared to those in control mice. KBP promoted the recruitment and M1 polarization of macrophages. Mechanistically, KBP upregulated iNOS by activating the Notch1/RBP-Jκ/Hes1 signalling pathway. Hes1 downregulated CYLD, a negative regulator of NF-κB signalling, and then activated the IKK/IκBα/NF-κB signalling pathway.

Conclusions

Our findings demonstrate that KBP is the key regulator of excessive inflammation in DFUs and provide a novel target for DFU therapy.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0376-9) contains supplementary material, which is available to authorized users.

Therapeutic strategies for enhancing angiogenesis in wound healing

The enhancement of wound healing has been a goal of medical practitioners for thousands of years. The development of chronic, non-healing wounds is a persistent medical problem that drives patient morbidity and increases healthcare costs. A key aspect of many non-healing wounds is the reduced presence of vessel growth through the process of angiogenesis. This review surveys the creation of new treatments for healing cutaneous wounds through therapeutic angiogenesis. In particular, we discuss the challenges and advancement that have been made in delivering biologic, pharmaceutical and cell-based therapies as enhancers of wound vascularity and healing.

Human umbilical cord mesenchymal stem cells implantation accelerates cutaneous wound healing in diabetic rats via the Wnt signaling pathway

OBJECTIVE

Difficulty in wound healing is one common complication of diabetes mellitus. The study explored whether the therapeutic effect of human umbilical cord mesenchymal stem cells (hUCMSCs) on diabetic ulcer wound was enhanced by the activation of the Wnt signaling pathway.

METHODS

Rat diabetic model was established by intraperitoneal injection of Streptozotocin (STZ). hUCMSCs were purified and seeded on the collagen-chitosan laser drilling acellular dermal matrix (CCLDADM) scaffold, which was subsequently implanted into the cutaneous wound of normal and diabetic rats, followed by daily injection of Wnt signaling pathway agonist (Wnt3a) or antagonist (sFRP3) at the edge of the scaffold. Wound healing was checked on days 7, 14, and 21, and the fibrous tissue deposition, capillaries, and epidermal regeneration at the wound were examined by hematoxylin-eosin staining. The hUCMSCs-CCLDADM scaffold was cultured in vitro and treated with Wnt3a or sFRP3, followed by evaluation of cell proliferation, cell proliferation rate, survival status, and altered protein levels in the Wnt signaling pathway using BrdU staining, CCK-8 assay, live/dead staining, and Western blotting, respectively.

RESULTS

On days 7 and 14 postoperatively, the speed of wound healing was significantly lower in diabetic rats than that in normal control rats. This phenomenon was significantly improved by the activation of the Wnt signaling pathway that also elevated the fibrous protein deposition and the abundance of capillary in the granulation tissue. Conversely, blockade of Wnt signaling slowed the healing of skin wound in diabetic rats. The activation of Wnt signaling pathway promoted the proliferation and differentiation and decreased the apoptosis of hUCMSCs, thereby elevating the number of living hUCMSCs on the CCLDADM scaffold, while the suppression exerted a contrary effect.

CONCLUSION

The activation of the Wnt signaling pathway promotes the healing of diabetic skin wound by the regulation of proliferation and differentiation of hUCMSCs on the CCLDADM scaffold.

Increased levels of serum pigment epithelium-derived factor aggravate proteinuria via induction of podocyte actin rearrangement

PURPOSE

To assess the role of serum pigment epithelium-derived factor (PEDF) in the occurrence and development of proteinuria and renal dysfunction and determine its relevant signaling pathway.

METHODS

We analyzed serum PEDF, creatinine, the urinary albumin-to-creatinine ratio, and renal morphology of normal or streptozotocin (STZ)-induced diabetic mice, before and after treatment with PEDF. In vitro, podocytes were stimulated with PEDF under normal or high-glucose conditions; permeability was measured by the transwell assay with fluorescein isothiocyanate (FITC)-dextran; and F-actin cytoskeleton was analyzed by phalloidin staining. Apoptosis was assessed by flow cytometry. RhoA activity and ROCK1, ZO-1, nephrin, and podocin levels were detected by Western blotting.

RESULTS

Diabetic mice exhibited a high serum PEDF level. In vivo, elevated serum PEDF led to proteinuria, increased serum creatinine, and podocyte foot process fusion in normal or diabetic mice. In vitro, both high-glucose and PEDF stimulation activated the RhoA/ROCK1 pathway in podocytes and promoted cell permeability, F-actin rearrangement, and apoptosis. Inhibition of RhoA/ROCK1 alleviated the damage from these effects.

CONCLUSIONS

Elevated serum PEDF aggravates the development of proteinuria and renal dysfunction by inducing F-actin arrangement, foot process fusion, and apoptosis of podocytes in both normal and diabetic mice, and this effect may be mediated by activation of the RhoA/ROCK1 pathway.

Involvement of glucose-regulated protein 78 and spliced X-box binding protein 1 in the protective effect of gliclazide in diabetic nephropathy

AIMS

To testing whether endoplasmic reticulum (ER) stress contributes to the development of diabetic nephropathy. Investigated the effect of gliclazide, an oral antihyperglycemic agent, in a rat model of diabetic nephropathy and the underlying mechanism related to the ER stress response.

METHODS

Sixty SD rats were divided into six groups. Diabetic nephropathy was induced in 30 rats with a streptozotocin (STZ) injection and high fat diet, which were then treated with saline, gliclazide or 4-PBA. 20 rats were treated with Tunicamycin (TM) one-time intraperitoneal injection, following treated with saline or gliclazide. Blood glucose, kidney index and function were evaluated. Light and transmission electron microscopy (TEM) were used to observe kidney histological changes. Quantitative real-time PCR and western blot were performed to access the mRNA and protein levels of glucose-regulated protein 78 (GRP78) and spliced X-box binding protein 1 (sXBP1) in glomeruli.

RESULT

STZ-induced diabetic rats evidenced nephropathy by higher serum creatinine (sCr), blood urea nitrogen (BUN), microalbuminuria (MAU), and kidney index. Histological examination and TEM assay showed abnormal renal structures including thick glomerular basement membrane and mesangial cell expansion. The same changes were found in TM-treated rats. Gliclazide-treated had similar kidney index, but lower glucose levels, sCr, BUN, and MAU, compared with both saline and 4-PBA-treated diabetic rats or saline-treated TM rats. Synchronize with significantly lower Grp78 and sXbp1 mRNA and protein levels.

CONCLUSION

Diabetes-induced nephropathy is associated with ER stress. Gliclazide treatment lessens diabetic nephropathy, probably partially by suppressing the GRP78- and sXBP1-mediated ER response.