Diabetic Microenvironment Research Articles

Antibacterial carboxymethyl chitosan hydrogel loaded with antioxidant cascade enzymatic system for immunoregulating the diabetic wound microenvironment

Diabetic wound healing faces several complex challenges, such as hypoxia, oxidative stress, and bacterial infections, which severely inhibit the wound-healing process. Herein, a quaternary ammonium salt-crosslinked carboxymethyl chitosan hydrogel (TPC) with excellent antioxidant and antibacterial properties was developed to immunoregulate the diabetic wound microenvironment. The TPC hydrogel was prepared by first mixing carboxymethyl chitosan (CMCS) and protocatechualdehyde (PA), followed by the addition of a quaternary ammonium cross-linker (TSPBA) and a superoxide dismutase (SOD)–catalase (CAT) cascade system. The immobilized SOD and CAT retained their activity, continuously converting endogenous ·O2− and H2O2 to O2 and H2O. PA also provided the TPC hydrogel excellent oxygen and nitrogen radical scavenging capacity. The quaternary ammonium groups in TSPBA significantly enhanced the inherent antibacterial ability of CMCS-based hydrogels. In diabetic wound-healing experiments, this porous and adhesive TPC hydrogel effectively closed wounds and regenerated skin tissue, resulting in shorter wound edges, thicker granulation, and higher collagen deposition levels compared with other groups. The TPC hydrogel also promoted macrophage polarization toward the M2 phenotype, accelerating wound healing by upregulating IL-10 expression, downregulating IL-6 expression, and enhancing angiogenesis. These results demonstrate the great potential of TPC hydrogel as a promising therapeutic dressing for treating diabetic wounds.

Exosomes Derived from Diabetic Microenvironment-Preconditioned Mesenchymal Stem Cells Ameliorate Nonalcoholic Fatty Liver Disease and Inhibit Pyroptosis of Hepatocytes

AimPyroptosis, a type of programmed cell death, is a key mechanism underlying non-alcoholic fatty liver disease (NAFLD). Mesenchymal stem cell (MSC)-derived exosomes (MSC-Exos) have the potential to ameliorate NAFLD, an effect that is enhanced by curcumin preconditioning. We previously reported that diabetic microenvironment preconditioning enhances the secretion capacity and anti-inflammatory activity of MSCs. Therefore, we hypothesized that MSC-Exos would inhibit hepatocyte pyroptosis and thereby ameliorate NAFLD, and that diabetic microenvironment preconditioning would enhance these effects. MethodsMSCs were preconditioned in a diabetic microenvironment (pMSCs). MSC-Exos and pMSC-Exos collected from MSCs or pMSCs were applied to methionine- and choline-deficient (MCD)-induced NAFLD mice and in vitro models involving induction with lipopolysaccharide or palmitic acid to mimic hepatic steatosis and injury. MCC950 treatment was used as a positive control. We analyzed the characteristics of NAFLD and pyroptosis markers. Protein profiles of MSC-Exos and pMSC-Exos were evaluated by label-free quantitative proteomics. ResultsIn vivo, MSC-Exos partially attenuated inflammation and fibrosis, but not lipid deposition and NAFLD progression in the livers of NAFLD mice. pMSC-Exos significantly improved lipid metabolism, hepatic steatosis, inflammation, and fibrosis but also retarded the progression of NAFLD. Pyroptosis was upregulated in the liver of NAFLD mice. MSC-Exos and pMSC-Exos inhibited pyroptosis, and the effect of the latter was greater than that of the former. In vitro, MSC-Exos and pMSC-Exos ameliorated hepatocyte steatosis, lipid metabolism disorder, and inflammation, and pMSC-Exos exerted a greater inhibitory effect on hepatocyte pyroptosis than MSC-Exos did, which were remitted after inhibition of peroxiredoxin-1 (PRDX-1). ConclusionMSC-Exos ameliorated NAFLD and inhibited hepatocyte pyroptosis by downregulating the NLRP3/Caspase-1/GSDMD pathway, effects enhanced by pMSC-Exos, partly due to PRDX-1 upregulation.

Proliferative Diabetic Retinopathy Microenvironment Drives Microglial Polarization and Promotes Angiogenesis and Fibrosis via Cyclooxygenase-2/Prostaglandin E2 Signaling

Diabetic retinopathy (DR) is the leading cause of visual impairment, particularly in the proliferative form (proliferative DR [PDR]). The impact of the PDR microenvironment on microglia, which are the resident immune cells in the central nervous system, and the specific pathological changes it may induce remain unclear. This study aimed to investigate the role of microglia in the progression of PDR under hypoxic and inflammatory conditions. We performed a comprehensive gene expression analysis using human-induced pluripotent stem cell-derived microglia under different stimuli (dimethyloxalylglycine (DMOG), lipopolysaccharide (LPS), and DMOG + LPS) to mimic the hypoxic inflammatory environment characteristic of PDR. Principal component analysis revealed distinct gene expression profiles, with 76 genes synergistically upregulated under combined stimulation. Notably, prostaglandin-endoperoxide synthase 2 (encoding cyclooxygenase (COX)-2) exhibited the most pronounced increase, leading to elevated prostaglandin E2 (PGE2) levels and driving pathological angiogenesis and inflammation via the COX-2/PGE2/PGE receptor 2 signaling axis. Additionally, the upregulation of the fibrogenic genes snail family transcriptional repressor 1 and collagen type I alpha 1 chain suggested a role for microglia in fibrosis. These findings underscore the critical involvement of microglia in PDR and suggest that targeting both the angiogenic and fibrotic pathways may present new therapeutic strategies for managing this condition.

NIR-II Image-Guided Wound Healing in Hypoxic Diabetic Foot Ulcers: The Potential of Ergothioneine-Luteolin-Chitin Hydrogels.

Hypoxic diabetic foot ulcers (HDFUs) pose a challenging chronic condition characterized by oxidative stress damage, bacterial infection, and persistent inflammation. This study introduces a novel therapeutic approach combining ergothioneine (EGT), luteolin (LUT), and quaternized chitosan oxidized dextran (QCOD) to address these challenges and facilitate wound healing in hypoxic DFUs. In vitro, assessments have validated the biosafety, antioxidant, and antimicrobial properties of the ergothioneine-luteolin-chitin (QCOD@EGT-LUT) hydrogel. Furthermore, near-infrared II (NIR-II) fluorescence image-guided the application of QCOD@EGT-LUT hydrogel in simulated HDFUs. Mechanistically, QCOD@EGT-LUT hydrogel modulates the diabetic wound microenvironment by reducing reactive oxygen species (ROS). In vivo studies demonstrated increased expression of angiogenic factors mannose receptor (CD206)and latelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), coupled with decreased inflammatory factors tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6), thereby promoting diabetic wound healing through up-regulation of transforming growth factor β-1 (TGF-β1).

Glucose-fueled cationic nanomotors for promoting the healing of infected diabetic wounds

Hyperglycemia-promoted bacterial infection will seriously exacerbate diabetic wounds, and its current clinical treatments are suffering from the adverse effects associated with off-target, bacterial resistance, and glycemic fluctuation. Herein, we present a kind of glucose-fueled cationic nanomotors capable of remarkably enhancing antibacterial efficacy, and thus expediting diabetic wound healing. The nanomotors have positively charged surfaces, and consist of mesoporous bowl-shaped polydopamine nanoparticles grafted with quaternized polymer brushes and coupled with glucose oxidase (GOx) and catalase (CAT). Stemming from the GOx-CAT cascade reaction in diabetic wound microenvironment, they can perform robust chemotactic motion towards both high glucose regions, where bacteria proliferation predominantly occurs, and elevated H2O2 levels, which bacterial metabolism produced. This enables the nanomotors to facilitate targeted migration towards bacteria-rich regions and simultaneous downregulation of glycemic levels, as well as to significantly enhance the electrostatic interaction between antibacterial components and bacteria. Consequently, the nanomotors exhibit amplified contact-killing effects of their attached cationic molecules, leading to an almost 10-fold enhancement in antibacterial efficacy compared to previous counterparts. The in vivo experiments approved that the nanomotors demonstrated the accelerated healing of infected diabetic wounds by S. aureus and biosafety. The results herein provide an insight into the clinical treatment of infected diabetic wounds.

Nanocarrier-Assisted Delivery of Berberine Promotes Diabetic Alveolar Bone Regeneration by Scavenging ROS and Improving Mitochondrial Dysfunction.

Oxidative stress and mitochondrial dysfunction are potential contributors to the compromised tissue regeneration capacity of alveolar bone in diabetic patients. Berberine, an active plant alkaloid, exhibits multiple pharmacological effects including antioxidation, blood glucose- and blood lipid-lowering properties. However, it remains uncertain whether berberine can improve impaired osteogenesis in type 2 diabetes mellitus (T2DM), and its poor solubility and oral bioavailability also constrain its applications in bone regeneration. Thus, our study aimed to probe the effects of berberine on bone marrow stem cells (BMSCs) in a diabetic microenvironment, with a greater emphasis on developing a suitable nano-delivery system for berberine and assessing its capability to repair diabetic alveolar bone defects. Firstly, BMSCs were exposed to berberine within a high glucose and palmitate (HG+PA) environment. Reactive oxygen species levels, mitochondrial membrane potential, ATP generation, cell apoptosis, and osteogenic potential were subsequently assessed. Next, we explored the regulatory mechanism of autophagy flux in the positive effects of berberine. Furthermore, a nanocarrier based on emulsion electrospinning for sustained local delivery of berberine (Ber@SF/PCL) was established. We assessed its capacity to enhance bone healing in the alveolar bone defect of T2DM rats through micro-computed tomography and histology analysis. Berberine treatment could inhibit reactive oxygen species overproduction, mitochondrial dysfunction, apoptosis, and improve osteogenesis differentiation by restoring autophagy flux under HG+PA conditions. Notably, Ber@SF/PCL electrospun nanofibrous membrane with excellent physicochemical properties and good biological safety had the potential to promote alveolar bone remodeling in T2DM rats. Our study shed new lights into the protective role of berberine on BMSCs under T2DM microenvironment. Furthermore, berberine-loaded composite electrospun membrane may serve as a promising approach for regenerating alveolar bone in diabetic patients.

Tea polyphenol nano-crosslinked dynamical hyaluronic acid-based hydrogel for diabetic wound healing

Diabetic wound healing remains a significant clinical challenge for the complex wound microenvironment characterized by oxidative stress, inflammation, and bacterial infection. To address these challenges, we present a novel hydrogel incorporates tea polyphenol-stabilized silver nanoparticles (TP@Ag NPs) into a dynamic hyaluronic acid-phenylboronic acid network crosslinked via borate ester bonds. This design leverages the inherent biocompatibility and biodegradability of hyaluronic acid alongside the antioxidant, anti-inflammatory, and antibacterial properties of tea polyphenols and silver nanoparticles. The HP-TP@Ag hydrogel exhibited glucose-responsive degradation and TP@Ag NPs release, enabling targeted delivery within the diabetic wound microenvironment. In vitro assays demonstrated the hydrogel's potent antioxidant activity, effectively scavenging ROS and protecting both HaCaT and RAW264.7 cells from oxidative stress. Furthermore, the HP-TP@Ag hydrogel significantly suppressed the production of pro-inflammatory cytokines and exhibited robust antibacterial activity against both E. coli and S. aureus. In vivo studies using a diabetic mouse model revealed accelerated wound closure, reduced inflammation, enhanced collagen deposition, and promoted angiogenesis and tissue remodeling in HP-TP@Ag hydrogel-treated wounds. These findings highlight the promise of HP-TP@Ag hydrogel as an advanced wound dressing for effective diabetic wound management, offering a synergistic approach to overcome the multifaceted challenges associated with this complex condition.

A ROS‐Responsive Lipid Nanoparticles Release Multifunctional Hydrogel Based on Microenvironment Regulation Promotes Infected Diabetic Wound Healing

AbstractThe continuous imbalance of the diabetic wound microenvironment is an important cause of chronic nonhealing, which manifests as a vicious cycle between excessive accumulation of reactive oxygen species (ROS) and abnormal healing. Regulating the microenvironment by suppressing wound inflammation, oxidative stress, and bacterial infection is a key challenge in treating diabetic wounds. In this study, ROS‐responsive hydrogels are developed composed of silk fibroin methacrylated (SFMA), modified collagen type III (rCol3MA), and lipid nanoparticles (LNPs). The newly designed hydrogel system demonstrated stable physicochemical properties and excellent biocompatibility. Moreover, the release of antimicrobial peptide (AMP) and puerarin (PUE) demonstrated remarkable efficacy in eradicating bacteria, regulating inflammatory responses, and modulating vascular functions. This multifunctional hydrogel is a simple and efficient approach for the treatment of chronic diabetic infected wounds and holds tremendous potential for future clinical applications.

Hydrogel Microsphere-Encapsulated Bimetallic Nanozyme for Promoting Diabetic Bone Regeneration via Glucose Consumption and ROS Scavenging.

The healing of bone defects among diabetic patients presents a critical challenge due to the pathological microenvironment, characterized by hyperglycemia, excessive reactive oxygen species (ROS) production, and inflammation. Herein, multifunctional composite microspheres, termed GMAP are developed, using a microfluidic technique by incorporating Au@Pt nanoparticles (NPs) and GelMA hydrogel to modulate the diabetic microenvironment for promoting bone regeneration. The GMAP enables the sustained release of Au@Pt NPs, which function as bimetallic nanozymes with dual enzyme-like activities involving glucose oxidase and catalase. The synergistic effect allows for efficient glucose consumption and ROS elimination concurrently. Thus, the GMAP effectively protects the proliferation of bone marrow mesenchymal stem cells (BMSCs) under adverse high-glucose conditions. Furthermore, it also promotes the osteogenic differentiation and paracrine capabilities of BMSCs, and subsequently inhibits inflammation and enhances angiogenesis. In vivo diabetic rats bone defect model, it is demonstrated that GMAP microspheres significantly improve bone regeneration, as verified by micro-computed tomography and histological examinations. This study provides a novel strategy for bone regeneration by modulating the diabetic microenvironment, presenting a promising approach for addressing the complex challenges associated with bone healing in diabetic patients.

Temperature-responsive self-contraction nanofiber/hydrogel composite dressing facilitates the healing of diabetic-infected wounds

Bacterial infections and long-term inflammation cause serious secondary damage to chronic diabetic wounds and hinder the wound healing processes. Currently, multifunctional hydrogels have shown promising effects in chronic wound repair. However, traditional hydrogels only keep the wound moist and protect it from bacterial infection, and cannot provide mechanical force to contract the wound edges to achieve facilitated wound closure. Here, an asymmetric composite dressing was created by combining biaxially oriented nanofibers and hydrogel, inspired by the double-layer structure of the traditional Chinese medicinal plaster patch, for managing chronic wounds. Specifically, electrospun Poly-(lactic acid-co-trimethylene carbonate) (PLATMC) nanofibers and methacrylate gelatin (GelMa) hydrogel loaded with Epinecidin-1@chitosan (Epi-1@CS) nanoparticles are assembled as the temperature-responsive self-contracting nanofiber/hydrogel (TSNH) composite dressing. The substrate layer of PLATMC nanofibers combines topological morphology with material properties to drive wound closure through temperature-triggered contraction force. The functional layer of GelMa hydrogel is loaded with Epi-1@CS nanoparticles that combine satisfactory cytocompatibility, and antioxidant, anti-inflammatory, and antibacterial properties. Strikingly, in vivo, the TSNH dressing could regulate the diabetic wound microenvironment, thereby promoting collagen deposition, facilitating angiogenesis, and reducing the inflammatory response, which promotes the rapid healing of chronic wounds. This study highlights the potential of synergizing mechanical and biochemical signals in enhancing chronic wound treatment. Overall, this TSNH composite dressing is provided as a reliable approach to solving the long-standing problem of chronically infected wound healing.

Enhancement of Bone Repair in Diabetic Rats with Metformin-Modified Silicified Collagen Scaffolds.

Regenerating bone defects in diabetic rats presents a significant challenge due to the detrimental effects of reactive oxygen species and impaired autophagy on bone healing. To address these issues, a metformin-modified biomimetic silicified collagen scaffold is developed utilizing the principles of biomimetic silicification. In vitro and in vivo experiments demonstrated that the scaffold enhanced bone tissue regeneration within the diabetic microenvironment through the release of dual bio-factors. Further analysis reveals a potential therapeutic mechanism whereby these dual bio-factors synergistically promoted osteogenesis in areas of diabetic bone defects by improving mitochondrial autophagy and maintaining redox balance. The present study provides critical insights into the advancement of tissue engineering strategies aimed at bone regeneration in diabetic patients. The study also sheds light on the underlying biological mechanisms.

Self-adaptive bioactive scaffolds orchestrate diabetic microenvironment remodeling and vascularized bone regeneration

The repair of diabetic bone defects is still challenging as the innate healing process is impaired by adverse microenvironments such as excessive reactive oxygen species (ROS) and insufficient angiogenesis and osteogenesis. Herein, a self-adaptive biocomposite scaffold that can orchestrate sequential regulation of diabetic microenvironment and vascularized bone regeneration was developed for efficient diabetic bone defect repair. The therapeutic scaffold system was meticulously constructed through the incorporation of hydrogel and 3D-printed architecture. In response to the multiple diabetic microenvironment (high level of glucose and ROS), the hydrogel consisting of Vitamin C-loaded phenylboric acid-grafted poly (glutamic acid)/poly (vinyl alcohol) showed adaptive degradation and antioxidative properties by scavenging the intracellular ROS, as well as promoting M2 polarization of macrophages. Furthermore, the copper-doped bioactive glass-contained 3D-printed polycaprolactone within the scaffold system was demonstrated to enhance the mechanical strength and stimulate the in vitro angiogenic and osteogenic performance by releasing copper and silicon ions. Moreover, in a diabetic rat femoral defect model, the biocomposite scaffold showed better angiogenesis and bone regeneration by following diabetic microenvironment remodeling. Therefore, the designed self-adaptive biocomposite scaffold can promote diabetic bone regeneration by sequentially regulating pathological and regenerative cues. This study offers vital insight into the design of a self-adaptive bioactive scaffold for the treatment of diabetic bone defects.

Multifunctional and immunoregulatory microenvironment-responsive hydrogel for whole course management of infected diabetic wounds

Infective diabetic wounds can significantly delay healing and pose severe infection risks. The process of infective diabetic wounds healing (DWH) are not only re-epithelialization and angiogenesis but also anti-bacterial, hair follicles regeneration and nerve growth. In this study, a stable dynamic hydrogel system was formulated by incorporating dynamic borate easter bond and carbon–carbon double bond, which based on tannic acid (TA) − acrylic phenyl boric acid (APBA) and acrylamide (AM). Subsequently, a hydrogel (ATAN-Met) was obtained by modifying the antibacterial ammonium cationic (N+) and loading metformin (Met). This system demonstrated impressive wet adhesion, self-healing, wearable and peelable properties, responding to glucose/reactive oxygen species (ROS) for drug release. In vitro and vivo experiments illustrated that ATAN-Met recruited mesenchymal stem cell (MSC), facilitating interaction between MSC and neural cells, regulating macrophage polarization, and modulating the diabetic wound microenvironment while exhibiting anti-bacterial property, ultimately leading to re-epithelialization and neurovascular-hair follicles regeneration. RNA and metabolomic sequencing indicated that ATAN-Met activate the Hippo pathway, inhibit the TNF pathway, and regulate wound metabolism to improve the diabetic wound microenvironment. These results suggest that the microenvironment-responsive ATAN-Met hydrogel shows considerable potential for the whole course management of infective DWH.

The Bioactive Interface of Titanium Implant with Both Anti-Oxidative Stress and Immunomodulatory Properties for Enhancing Osseointegration under Diabetic Condition.

The poor implant-osseointegration under diabetic condition remains a challenge to be addressed urgently. Studies have confirmed that the diabetic pathological microenvironment is accompanied by excessive oxidative stress, imbalanced immune homeostasis, and persistent chronic inflammation, which seriously impairs the osteogenic process. Herein, a multifunctional bioactive interface with both anti-oxidative stress and immunomodulatory properties is constructed on titanium implants. Briefly, manganese dioxide nanosheets are coated onto mesoporous polydopamine nanoparticles loaded with carbon monoxide gas precursor, namely MnO2-CO@MPDA NPs, and then they are integrated on the titanium implant to obtain MCM-Ti. In the simulated diabetic microenvironment, under the action of MnO2 nanoenzymes, MCM-Ti can effectively eliminate intracellular reactive oxygen species while alleviating hypoxic state. Interestingly, the microenvironment mediates the responsive release of CO gas, which effectively drives macrophages toward M2 polarization, thereby ameliorating inflammatory response. The potential mechanism is that CO gas up-regulates the expression of heme oxygenase-1, further activating the Notch/Hes1/Stat3 signaling pathway. Furthermore, the conditioned medium derived from macrophages on MCM-Ti surface significantly enhances the osteogenic differentiation of BMSCs. In a type 2 diabetic rat model, MCM-Ti implant effectively alleviates the accompanying inflammation and enhances the osseointegration through the synergistic effects of resisting oxidative stress and remodeling immune homeostasis.

Design and development of titanium-coated implants with advanced antioxidant properties for enhanced regenerative repair of diabetic bone

The aging population is closely associated with chronic metabolic diseases, including diabetes, hypertension, and other metabolic disorders. Metabolic dysfunction is a primary characteristic of diabetic patients, which can impair cellular response to insulin and lead to increased production of reactive oxygen species (ROS), hindering bone healing. Therefore, the development of multifunctional titanium (Ti) implants with the ability to eliminate reactive oxygen and promote bone formation is the optimal strategy to address this issue. In this study, we designed a thioctic acid(Ta) coating loaded with strontium(Sr), forming a strong bond with the Ti implant (Ti-Ta@Sr). During treatment, sulfuric acid demonstrated the ability to release monomers in the early stages, effectively eliminating excess reactive oxygen produced in high-glucose environments and regulating the diabetic microenvironment. The delayed in-situ release of strontium ions also enhanced osteogenic differentiation efficiency. Both in vivo and in vitro experiments confirmed that Ti-Ta@Sr significantly restored the osteogenic capacity and proliferation of osteoblasts under high-glucose conditions. These advantages make Ti-Ta@Sr a promising candidate material for orthopedic implants, suitable for repairing bone defects in diabetic patients.

A nanoenzyme reactor fueled by a High-Glucose microenvironment for augmented diabetic tumor therapy

Diabetes is recognized as an independent risk factor for the onset and advancement of cancer. However, there has been limited emphasis on investigating the diabetic tumor microenvironment (TME) and harnessing its inherent microenvironmental distinctions to facilitate tumor ablation. The management of cancer with diabetes is often challenging. Herein, an activatable hollow mesoporous manganese silicate (H-Mn)/indocyanine green (ICG)/glucose oxidase (GOX) nanoenzyme (H-MIG) was developed for diabetic tumor therapy. This micro-reactor consumes glucose to trigger a sequential cascade reaction to biologically amplify the antitumor effect under hyperglycemia conditions. H-Mn degrades within the TME, releasing O2 and Mn2+. The presence of O2 promotes GOX-induced glucose consumption, leading to the subsequent production of H2O2. This glucose-fueled oxidation also provides reactants for chemodynamic therapy, as H2O2 and Mn2+ in the TME subsequently undergo a Fenton-like reaction. In addition, by inhibiting the expression of the heat shock protein 90, which is highly expressed in diabetic TME, GOX enhances ICG-guided mild-temperature photothermal therapy. In vitro and in vivo experiments demonstrated that the domino effect fueled by this high-glucose TME improves anticancer efficacy. By exploiting the complementary cascade reactions, this endogenous enzyme-based strategy could inspire the design of more promising advanced platforms for more efficient diabetic cancer therapy.

Exosomes derived from umbilical cord-derived mesenchymal stem cells exposed to diabetic microenvironment enhance M2 macrophage polarization and protect against diabetic nephropathy.

The role of mesenchymal-stem-cell-derived exosomes (MSCs-Exo) in the regulation of macrophage polarization has been recognized in several diseases. There is emerging evidence that MSCs-Exo partially prevent the progression of diabetic nephropathy (DN). This study aimed to investigate whether exosomes secreted by MSCs pre-treated with a diabetic environment (Exo-pre) have a more pronounced protective effect against DN by regulating the balance of macrophages. Exo-pre and Exo-Con were isolated from the culture medium of UC-MSCs pre-treated with a diabetic mimic environment and natural UC-MSCs, respectively. Exo-pre and Exo-Con were injected into the tail veins of db/db mice three times a week for 6 weeks. Serum creatinine and serum urea nitrogen levels, the urinary protein/creatinine ratio, and histological staining were used to determine renal function and morphology. Macrophage phenotypes were analyzed by immunofluorescence, western blotting, and quantitative reverse transcription polymerase chain reaction. Invitro, lipopolysaccharide-induced M1 macrophages were incubated separately with Exo-Con and Exo-pre. We performed microRNA (miRNA) sequencing to identify candidate miRNAs and predict their target genes. An miRNA inhibitor was used to confirm the role of miRNAs in macrophage modulation. Exo-pre were more potent than Exo-Con at alleviating DN. Exo-pre administration significantly reduced the number of M1 macrophages and increased the number of M2 macrophages in the kidney compared to Exo-Con administration. Parallel outcomes were observed in the co-culture experiments. Moreover, miR-486-5p was distinctly expressed in Exo-Con and Exo-pre groups, and it played an important role in macrophage polarization by targeting PIK3R1 through the PI3K/Akt pathway. Reducing miR-486-5p levels in Exo-pre abolished macrophage polarization modulation. Exo-pre administration exhibited a superior effect on DN by remodeling the macrophage balance by shuttling miR-486-5p, which targets PIK3R1.

Simultaneous regulation of AGE/RAGE signaling and MMP-9 expression by an immunomodulating hydrogel accelerates healing in diabetic wounds

PurposeIn chronic hyperglycemia, the advanced glycation end product (AGE) interacts with its receptor (RAGE) and contributes to impaired wound healing by inducing oxidative stress, generating dysfunctional macrophages, and prolonging the inflammatory response. Additionally, uncontrolled levels of proteases, including metallomatrix protease-9 (MMP-9), in the diabetic wound bed degrade the extracellular matrix (ECM) and biological cues that augment healing. A multifunctional antimicrobial hydrogel (Immuno-gel) containing RAGE and MMP-9 inhibitors can regulate the wound microenvironment and promote scar-free healing. ResultsImmuno-gel was characterized and the wound healing efficacy was determined in vitro cell culture and in vivo diabetic Wistar rat wound model using ELISA, Western blot, and Immunofluorescence staining. The Immuno-gel exhibited a highly porous morphology with excellent in vitro cytocompatibility. AGE-stimulated macrophages treated with the Immuno-gel released higher levels of pro-healing cytokines in vitro. In the hydrogel-wound interface of diabetic Wistar rats, Immuno-gel treatment significantly reduced MMP-9 and NF-κB expression and enhanced pro-healing (M2) macrophage population and pro-healing cytokines. ConclusionAltogether, this study suggests that Immuno-gel simultaneously attenuates macrophage dysfunction through the inhibition of AGE/RAGE signaling and reduces MMP-9 overexpression, both of which favor scar-free healing. The combinatorial treatment with RAGE and MMP-9 inhibitors via Immuno-gel simultaneously modulates the diabetic wound microenvironment, making it a promising novel treatment to accelerate diabetic wound healing.

Diabetic microenvironment deteriorates the regenerative capacities of adipose mesenchymal stromal cells

BackgroundType 2 diabetes is an endocrine disorder characterized by compromised insulin sensitivity that eventually leads to overt disease. Adipose stem cells (ASCs) showed promising potency in improving type 2 diabetes and its complications through their immunomodulatory and differentiation capabilities. However, the hyperglycaemia of the diabetic microenvironment may exert a detrimental effect on the functionality of ASCs. Herein, we investigate ASC homeostasis and regenerative potential in the diabetic milieu.MethodsWe conducted data collection and functional enrichment analysis to investigate the differential gene expression profile of MSCs in the diabetic microenvironment. Next, ASCs were cultured in a medium containing diabetic serum (DS) or normal non-diabetic serum (NS) for six days and one-month periods. Proteomic analysis was carried out, and ASCs were then evaluated for apoptosis, changes in the expression of surface markers and DNA repair genes, intracellular oxidative stress, and differentiation capacity. The crosstalk between the ASCs and the diabetic microenvironment was determined by the expression of pro and anti-inflammatory cytokines and cytokine receptors.ResultsThe enrichment of MSCs differentially expressed genes in diabetes points to an alteration in oxidative stress regulating pathways in MSCs. Next, proteomic analysis of ASCs in DS revealed differentially expressed proteins that are related to enhanced cellular apoptosis, DNA damage and oxidative stress, altered immunomodulatory and differentiation potential. Our experiments confirmed these data and showed that ASCs cultured in DS suffered apoptosis, intracellular oxidative stress, and defective DNA repair. Under diabetic conditions, ASCs also showed compromised osteogenic, adipogenic, and angiogenic differentiation capacities. Both pro- and anti-inflammatory cytokine expression were significantly altered by culture of ASCs in DS denoting defective immunomodulatory potential. Interestingly, ASCs showed induction of antioxidative stress genes and proteins such as SIRT1, TERF1, Clusterin and PKM2.ConclusionWe propose that this deterioration in the regenerative function of ASCs is partially mediated by the induced oxidative stress and the diabetic inflammatory milieu. The induction of antioxidative stress factors in ASCs may indicate an adaptation mechanism to the increased oxidative stress in the diabetic microenvironment.

Dual-responsive metal polyphenol network nanosheets for diabetic wound healing

Diabetic wound healing poses a significant challenge in the biomedical domain. Inadequate angiogenesis and fibroblast dysfunction are two primary characteristics of diabetic microenvironment. Fibroblast dysfunction is characterized by excessive accumulation of reactive oxygen species (ROS) and fragmented mitochondria. Herein, we developed a microenvironment responsive zinc–gallic acid nanosheets (ZnGA NSs) for diabetic wound healing, which slowly release Zn2+ and gallic acid (GA) in response to low pH and excessive ROS. The released Zn2+ enhanced cell proliferation, migration, and endothelial tube formation. And the released GA activated antioxidant enzyme system via the KEAP1/NRF2 pathway and promoted mitochondrial fusion by upregulating MFN1/2 and OPA1, which ultimately reprograms dysfunctional fibroblast. The application of ZnGA NSs effectively facilitated wound healing in a rat diabetic model with full-thickness cutaneous defects. More importantly, skin wounds treated with ZnGA NSs exhibited enhanced angiogenesis, alleviated inflammation, and improved tissue regeneration. These findings highlight the potential of ZnGA NSs as a promising therapeutic modality for diabetic wound treatment.