Liraglutide via Activation of AMP-Activated Protein Kinase-Hypoxia Inducible Factor-1α-Heme Oxygenase-1 Signaling Promotes Wound Healing by Preventing Endothelial Dysfunction in Diabetic Mice

Sitagliptin Ameliorates Creb5/lncRNA ENSMUST00000213271-Mediated Vascular Endothelial Dysfunction in Obese Mice

PURPOSE

Obesity is mediated by the changes in dyslipidemia, oxidative stress, and inflammation, leading to vascular endothelial dysfunction. Glucagon-like peptide-1 (GLP-1) analogues and dipeptidyl peptidase-4 inhibitors prevent the development of endothelial dysfunction. However, the underlying mechanism still remains largely unclear. Long non-coding RNAs (lncRNAs), one class of non-coding small RNAs, have been shown to exert a regulatory impact on the endothelial function in obesity. This study aimed to investigate whether the elevation of GLP-1 by a DPP-4 inhibitor sitagliptin improved vascular endothelial function by modulating lncRNAs in obese mice and to clarify the underlying molecular mechanism.

METHODS

Male C57BL/6J mice were fed a high-fat diet for 4 months to induce obesity and some obese mice were treated with sitagliptin for the last 1 month. Levels of total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and glucagon-like peptide-1 (GLP-1) in plasma were detected by ELISA. LncRNA expression profile was analyzed via microarray. Aortic relaxations were examined by myograph. Protein expressions and phosphorylations were determined using western blot. The differentially expressed lncRNAs were validated using qRT-PCR.

RESULTS

Obese mice exhibited increased levels of TC and LDL, decreased concentrations of HDL and GLP-1 in plasma, and impaired aortic endothelium-dependent relaxations; such effects could be reversed by sitagliptin. Moreover, the altered expression profile of lncRNAs in the obese mouse aortae could be modulated by sitagliptin. Consistent with microarray analysis, qRT-PCR also revealed that lncRNA ENSMUST00000213271 was up-regulated in obese mouse aortae and aortic endothelial cells (ECs), which could be down-regulated by sitagliptin. Creb5 silencing reduced lncRNA ENSMUST00000213271 in obese mouse ECs. Knockdown of either Creb5 or lncRNA ENSMUST00000213271 restored the activation of AMPK/eNOS in obese mouse ECs. Furthermore, sitagliptin also suppressed Creb5 and lncRNA ENSMUST00000213271 and increased the phosphorylations of AMPK and eNOS in obese mice.

CONCLUSION

Creb5/lncRNA ENSMUST00000213271 mediated vascular endothelial dysfunction through inhibiting AMPK/eNOS cascade in obesity. Elevation of GLP-1 by sitagliptin possibly improved endothelial function by suppressing Creb5/lncRNA ENSMUST00000213271 and subsequently restoring AMPK/eNOS activation in obese mice. This study will provide new evidence for the benefits of GLP-1 against vasculopathy in obesity.

GLI family zinc finger protein 2 promotes skin fibroblast proliferation and DNA damage repair by targeting the miR-200/ataxia telangiectasia mutated axis in diabetic wound healing

Diabetic foot ulcer (DFU) is a serious complication of diabetic patients which negatively affects their foot health. This study aimed to estimate the role and mechanism of the miR-200 family in DNA damage of diabetic wound healing. Human foreskin fibroblasts (HFF-1 cells) were stimulated with high glucose (HG). Db/db mice were utilized to conduct the DFU in vivo model. Cell viability was evaluated using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assays. Superoxide dismutase activity was determined using detection kits. Reactive oxygen species determination was conducted via dichlorodihydrofluorescein-diacetate assays. Enzyme-linked immunosorbent assay was used to evaluate 8-oxo-7,8-dihydro-2'deoxyguanosine levels. Genes and protein expression were analyzed by quantitative real-time polymerase chain reaction, western blotting, or immunohistochemical analyses. Luciferase reporter gene and RNA immunoprecipitation assays determined the interaction with miR-200a/b/c-3p and GLI family zinc finger protein 2 (GLI2) or ataxia telangiectasia mutated (ATM) kinase. HG repressed cell proliferation and DNA damage repair, promoted miR-200a/b/c-3p expression, and suppressed ATM and GLI2. MiR-200a/b/c-3p inhibition ameliorated HG-induced cell proliferation and DNA damage repair repression. MiR-200a/b/c-3p targeted ATM. Then, the silenced ATM reversed the miR-200a/b/c-3p inhibition-mediated alleviative effects under HG. Next, GLI2 overexpression alleviated the HG-induced cell proliferation and DNA damage repair inhibition via miR-200a/b/c-3p. MiR-200a/b/c-3p inhibition significantly promoted DNA damage repair and wound healing in DFU mice. GLI2 promoted cell proliferation and DNA damage repair by regulating the miR-200/ATM axis to enhance diabetic wound healing in DFU.

M2 macrophage-derived exosomes induce angiogenesis and increase skin flap survival through HIF1AN/HIF-1α/VEGFA control

BACKGROUND

Skin flap transplantation is a routine strategy in plastic and reconstructive surgery for skin-soft tissue defects. Recent research has shown that M2 macrophages have the potential for pro-angiogenesis during tissue healing.

METHODS

In our research, we extracted the exosomes from M2 macrophages(M2-exo) and applied the exosomes in the model of skin flap transplantation. The flap survival area was measured, and the choke vessels were assessed by morphological observation. Hematoxylin and eosin (H&E) staining and Immunohistochemistry were applied to assess the neovascularization. The effect of M2-exo on the function of Human umbilical vein endothelial cells (HUVECs) was also investigated. We also administrated 2-methoxyestradiol (2-ME2, an inhibitor of HIF-1α) to explore the underlying mechanism. We tested the effects of M2-Exo on the proliferation of HUVECs through CCK8 assay and EdU staining assay.

RESULTS

The survival area and number of micro-vessels in the skin flaps were increased in the M2-exo group. Besides, the dilation rate of choke vessels was also enhanced in the M2-exo group. Additionally, compared with the control group, M2-exo could accelerate the proliferation, migration and tube formation of HUVECs in vitro. Furthermore, the expression of the pro-angiogenesis factors, HIF-1α and VEGFA, were overexpressed with the treatment of the M2-exo. The expression of HIF1AN protein level was decreased in the M2-exo group. Finally, treatment with HIF-1α inhibitor reverses the pro-survival effect of M2-exo on skin flaps by interfering with the HIF1AN/HIF-1α/VEGFA signaling pathway.

CONCLUSION

This study showed that M2-exosomes promote skin flap survival by enhancing angiogenesis, with HIF1AN/HIF-1α/VEGFA playing a crucial role in this process.

A comprehensive review on the composition, biogenesis, purification, and multifunctional role of exosome as delivery vehicles for cancer therapy

All forms of life produce nanosized extracellular vesicles called exosomes, which are enclosed in lipid bilayer membranes. Exosomes engage in cell-to-cell communication and participate in a variety of physiological and pathological processes. Exosomes function via their bioactive components, which are delivered to target cells in the form of proteins, nucleic acids, and lipids. Exosomes function as drug delivery vehicles due to their unique properties of innate stability, low immunogenicity, biocompatibility, biodistribution, accumulation in desired tissues, low toxicity in normal tissues, and the stimulation of anti-cancer immune responses, and penetration capacity into distance organs. Exosomes mediate cellular communications by delivering various bioactive molecules including oncogenes, oncomiRs, proteins, specific DNA, messenger RNA (mRNA), microRNA (miRNA), small interfering RNA (siRNA), and circular RNA (circRNA). These bioactive substances can be transferred to change the transcriptome of target cells and influence tumor-related signaling pathways. After considering all of the available literature, in this review we discuss the biogenesis, composition, production, and purification of exosomes. We briefly review exosome isolation and purification techniques. We explore great-length exosomes as a mechanism for delivering a variety of substances, including proteins, nucleic acids, small chemicals, and chemotherapeutic drugs. We also talk about the benefits and drawbacks of exosomes. This review concludes with a discussion future perspective and challenges. We hope that this review will provide us a better understanding of the current state of nanomedicine and exosome applications in biomedicine.

The use of sodium-glucose co-transporter-2 inhibitors or glucagon-like peptide-1 receptor agonists versus sulfonylureas and the risk of lower limb amputations: a nation-wide cohort study

BACKGROUND

Numerous studies have investigated the potential association of sodium-glucose co-transporter-2 inhibitors (SGLT2-Is) with an increased risk of lower limb amputations (LLAs), but have produced conflicting results. Particularly studies comparing SGLT2-Is to glucagon-like peptide-1 receptor agonists (GLP1-RAs) seem to find a higher LLA risk with SGLT2-I use. This raises the question whether the results are driven by a protective GLP1-RA-effect rather than a harmful SGLT2-I-effect. GLP1-RAs could promote wound healing and therefore reduce the risk of LLAs, but the associations between both drug classes and LLA remain uncertain. Therefore, the aim of the current study was to investigate the risk of LLA and diabetic foot ulcer (DFU) with SGLT2-I use and GLP1-RA use versus sulfonylurea use.

METHODS

A retrospective population-based cohort study was conducted using data from the Danish National Health Service (2013-2018). The study population (N = 74,475) consisted of type 2 diabetes patients aged 18 + who received a first ever prescription of an SGLT2-I, GLP1-RA or sulfonylurea. The date of the first prescription defined the start of follow-up. Time-varying Cox proportional hazards models estimated the hazard ratios (HRs) of LLA and DFU with current SGLT2-I use and GLP1-RA use versus current SU use. The models were adjusted for age, sex, socio-economic variables, comorbidities and concomitant drug use.

RESULTS

Current SGLT2-I use was not associated with a higher risk of LLA versus sulfonylureas {adjusted HR 1.10 [95% confidence interval (CI) 0.71-1.70]}. Current GLP1-RA use, on the other hand, was associated with a lower risk of LLA [adjusted HR 0.57 (95%CI 0.39-0.84)] compared to sulfonylureas. The risk of DFU was similar to that with sulfonylureas with both exposures of interest.

CONCLUSION

SGLT2-I use was not associated with a higher risk of LLA, but GLP1-RAs with a lower risk of LLA. Previous studies reporting a higher risk of LLA with SGLT2-I use compared to GLP1-RA use might have been looking at a protective GLP1-RA effect, rather than a harmful SGLT2-I effect.

Adiponectin as a therapeutic target for diabetic foot ulcer

The global burden of diabetic foot ulcers (DFUs) is a significant public health concern, affecting millions of people worldwide. These wounds cause considerable suffering and have a high economic cost. Therefore, there is a need for effective strategies to prevent and treat DFUs. One promising therapeutic approach is the use of adiponectin, a hormone primarily produced and secreted by adipose tissue. Adiponectin has demonstrated anti-inflammatory and anti-atherogenic properties, and researchers have suggested its potential therapeutic applications in the treatment of DFUs. Studies have indicated that adiponectin can inhibit the production of pro-inflammatory cytokines, increase the production of vascular endothelial growth factor, a key mediator of angiogenesis, and inhibit the activation of the intrinsic apoptotic pathway. Additionally, adiponectin has been found to possess antioxidant properties and impact glucose metabolism, the immune system, extracellular matrix remodeling, and nerve function. The objective of this review is to summarize the current state of research on the potential role of adiponectin in the treatment of DFUs and to identify areas where further research is needed in order to fully understand the effects of adiponectin on DFUs and to establish its safety and efficacy as a treatment for DFUs in the clinical setting. This will provide a deeper understanding of the underlying mechanisms of DFUs that can aid in the development of new and more effective treatment strategies.

Diabetic foot ulcer: Challenges and future

Diabetic foot ulcers (DFUs) have become one of the important causes of mortality and morbidity in patients with diabetes, and they are also a common cause of hospitalization, which places a heavy burden on patients and society. The prevention and treatment of DFUs requires multidisciplinary management. By controlling various risk factors, such as blood glucose levels, blood pressure, lipid levels and smoking cessation, local management of DFUs should be strengthened, such as debridement, dressing, revascularization, stem cell decompression and oxygen therapy. If necessary, systemic anti-infection treatment should be administered. We reviewed the progress in the clinical practice of treating DFUs in recent years, such as revascularization, wound repair, offloading, stem cell transplantation, and anti-infection treatment. We also summarized and prospectively analyzed some new technologies and measurements used in the treatment of DFUs and noted the future challenges and directions for the development of DFU treatments.

A Nanozyme-Immobilized Hydrogel with Endogenous ROS-Scavenging and Oxygen Generation Abilities for Significantly Promoting Oxidative Diabetic Wound Healing

Non-healing wound is a common complication of diabetic patients associated with high morbidity and mortality. Engineered therapeutic hydrogels have enviable advantages in tissue regeneration, however, they are suboptimal for the healing of diabetic wounds characterized by reactive oxygen species (ROS) accumulation and chronic hypoxia. Here, a unique biological metabolism-inspired hydrogel, for ameliorating this hostile diabetic microenvironment, is presented. Consisting of natural polymers (hydrazide modified hyaluronic acid and aldehyde modified hyaluronic acid) and a metal-organic frameworks derived catalase-mimic nanozyme (ε-polylysine coated mesoporous manganese cobalt oxide), the engineered nanozyme-reinforced hydrogels can not only capture the endogenous elevated ROS in diabetic wounds, but also synergistically produce oxygen through the ROS-driven oxygen production ability. These fascinating properties of hydrogels protect skin cells (e.g., keratinocytes, fibroblasts, and vascular endothelial cells) from ROS and hypoxia-mediated death and proliferation inhibition. Diabetic wounds treated with the nanozyme-reinforced hydrogels highlight the potential of inducing the macrophages polarization from pro-inflammatory phenotype (M1) to anti-inflammatory subtype (M2). The hydrogel dressings demonstrate a prominently accelerated healing rate as shown by alleviating the excessive inflammatory, inducing efficiently proliferation, re-epithelialization, collagen deposition, and neovascularization. This work provides an effective strategy based on nanozyme-reinforced hydrogel as a ROS-driven oxygenerator for enhancing diabetic wound healing.

Polyphosphate in Chronic Wound Healing: Restoration of Impaired Metabolic Energy State

Many pathological conditions are characterized by a deficiency of metabolic energy. A prominent example is nonhealing or difficult-to-heal chronic wounds. Because of their unique ability to serve as a source of metabolic energy, inorganic polyphosphates (polyP) offer the opportunity to develop novel strategies to treat such wounds. The basis is the generation of ATP from the polymer through the joint action of two extracellular or plasma membrane-bound enzymes alkaline phosphatase and adenylate kinase, which enable the transfer of energy-rich phosphate from polyP to AMP with the formation of ADP and finally ATP. Building on these findings, it was possible to develop novel regeneratively active materials for wound therapy, which have already been successfully evaluated in first studies on patients.