Diabetic Mouse Model Research Articles

Antidiabetic potential of Selenium nanoparticles and plasma-rich platelets in diabetic mice

Diabetes mellitus is a widespread endocrine disorder, which is categorized as the fourth leading cause of global mortality. Allopathic medicine has yet to provide a satisfactory cure for this condition. Consequently, there is an urgent demand for innovative antidiabetic treatment approaches with enhanced management and minimum side effects and costs. The study investigated the synergistic antidiabetic potential of combining selenium nanoparticles (Se NPs) and plasma-rich platelets (PRP) in diabetic mice. Antidiabetic activity of the proposed combination (Se NPs and PRP) was evaluated from histopathological and biochemical perspectives. The experiment involved alloxan monohydrate induced diabetic mouse model. In the in vivo study, several biochemical parameters for assessing the antidiabetic effect of the novel combination of (Se NPs and PRP) were performed such as blood glucose levels, body weight, lipid profiles, and liver damage markers (AST and ALT). Scavenging antioxidant activity was assessed by evaluation levels of hepatic and renal GSH, MDA, SOD, and CAT activities. Complete histopathological examinations of vital internal organs were carried out. Results revealed that combining Se NPs and PRP presents a novel approach for better diabetes management and reduced complications associated with the disease. These findings have therapeutic implications for managing diabetes mellitus.

Dual phage-incorporated electrospun polyvinyl alcohol-eudragit nanofiber matrix for rapid healing of diabetic wound infected by Pseudomonas aeruginosa and Staphylococcus aureus.

Diabetic wound healing remains a healthcare challenge due to co-occurring multidrug-resistant (MDR) bacterial infections and the constraints associated with sustained drug delivery. Here, we integrate two new species of phages designated as PseuPha1 and RuSa1 respectively lysing multiple clinical MDR strains of P. aeruginosa and S. aureus into a novel polyvinyl alcohol-eudragit (PVA-EU†) nanofiber matrix through electrospinning for rapid diabetic wound healing. PVA-EU† evaluated for characteristic changes that occurred due to electrospinning and subjected to elution, stability and antibacterial assays. The biocompatibility and wound healing ability of PVA-EU† were assessed through mouse fibroblast cell line NIH3T3, followed by validation through diabetic mice excision wound co-infected with P. aeruginosa and S. aureus. The electrospinning resulted in the incorporation of ~ 75% active phages at PVA-EU†, which were stable at 25°C for 30days and at 4°C for 90days. PVA-EU† showed sustained release of phages for 18h and confirmed to be detrimental to both mono- and mixed-cultures of target pathogens. The antibacterial activity of PVA-EU† remained unaltered in the presence of high amounts of glucose, whereas alkaline pH promoted the activity. The matrix exerted no cytotoxicity on NIH3T3, but showed significant (p < 0.0001) wound healing in vitro and the process was rapid as validated through a diabetic mice model. The sustained release, quick wound closure, declined abundance of target MDR bacteria in situ and histopathological signs of recovery corroborated the therapeutic efficacy of PVA-EU†. Taken together, our data signify the potential application of PVA-EU† in the rapid treatment of diabetic wounds without the aid of antibiotics.

Knockout of C1q/tumor necrosis factor-related protein-9 aggravates cardiac fibrosis in diabetic mice by regulating YAP-mediated autophagy.

Diabetic cardiomyopathy (DCM) is predominantly distinguished by impairment in ventricular function and myocardial fibrosis. Previous studies revealed the cardioprotective properties of C1q/tumor necrosis factor-related protein 9 (CTRP9). However, whether CTRP9 affects diabetic myocardial fibrosis and its underlying mechanisms remains unclear. We developed a type 1 diabetes (T1DM) model in CTRP9-KO mice via streptozotocin (STZ) induction to examine cardiac function, histopathology, fibrosis extent, Yes-associated protein (YAP) expression, and the expression of markers for autophagy such LC3-II and p62. Additionally, we analyzed the direct impact of CTRP9 on high glucose (HG)-induced transdifferentiation, autophagic activity, and YAP protein levels in cardiac fibroblasts. In diabetic mice, CTRP9 expression was decreased in the heart. The absence of CTRP9 aggravated cardiac dysfunction and fibrosis in mice with diabetes, alongside increased YAP expression and impaired autophagy. In vitro, HG induced the activation of myocardial fibroblasts, which demonstrated elevated cell proliferation, collagen production, and α-smooth muscle actin (α-SMA) expression. CTRP9 countered these adverse effects by restoring autophagy and reducing YAP protein levels in cardiac fibroblasts. Notably, the protective effects of CTRP9 were negated by the inhibition of autophagy with chloroquine (CQ) or by YAP overexpression through plasmid intervention. Notably, the protective effect of CTRP9 was negated by inhibition of autophagy caused by chloroquine (CQ) or plasmid intervention with YAP overexpression. Our findings suggest that CTRP9 can enhance cardiac function and mitigate cardiac remodeling in DCM through the regulation of YAP-mediated autophagy. CTRP9 holds promise as a potential candidate for pharmacotherapy in managing diabetic cardiac fibrosis.

Methionine sulfoxide reductase B2 protects against cardiac complications in diabetes mellitus

Diabetes mellitus (DM) is a progressive, chronic metabolic disorder characterized by high oxidative stress, which can lead to cardiac damage. Methionine sulfoxylation (MetO) of proteins by excessive reactive oxygen species (ROS) can impair the basic functionality of essential cellular proteins, contributing to heart failure. Methionine sulfoxide reductase B2 (MsrB2) can reverse oxidation induced MetO in mitochondrial proteins, so we investigated its role in diabetic cardiomyopathy. We observed that DM-induced heart damage in diabetic mice model is characterized by increased ROS, increased protein MetO with mitochondria structural pathology, and cardiac fibrosis. In addition, MsrB2 was significantly increased in mouse DM cardiomyocytes, supporting the induction of a protective process. Further, MsrB2 directly induces Parkin and LC3 activation (mitophagy markers) in cardiomyocytes. In MsrB2, knockout mice displayed abnormal electrophysiological function, as determined by ECG analysis. Histological analysis confirmed increased cardiac fibrosis and disrupted cardiac tissue in MsrB2 knockout DM mice. We then corroborated our findings in human DM heart samples. Our study demonstrates that increased MsrB2 expression in the heart protects against diabetic cardiomyopathy.Graphic

Exosomes derived from cord blood Treg cells promote diabetic wound healing by targeting monocytes

Chronic nonhealing diabetic wounds are a critical clinical challenge. Regulatory T cells (Tregs) are immunosuppressive modulators affecting wound healing progression by controlling the inflammatory response. The current study attempted to investigate whether the exosomes derived from cord blood (CB) Tregs can accelerate the healing process. Exosomes were isolated from CB-Treg cultures using ultracentrifugation and validated with different specific markers of exosomes. The purified CB-Treg-derived exosomes were co-cultured with peripheral blood mononuclear cells (PBMCs) and CD14+ monocytes. The migration-promoting effect of CB-Treg-derived exosomes on fibroblasts and endothelial cells was investigated. We used thermosensitive Pluronic F-127 hydrogel (PF-127) loaded with CB-Treg-derived exosomes in a diabetic wound healing mouse model. CB-Treg-derived exosomes with 30–120 nm diameters revealed exosome-specific markers, such as TSG101, Alix, and CD63. CB-Treg-derived exosomes were mainly bound to the monocytes when co-cultured with PBMCs, and promoted monocyte polarization to the anti-inflammatory phenotype (M2) in vitro. CB-Treg-derived exosomes enhanced the migration of endothelial cells and fibroblasts. Furthermore, CB-Treg-derived exosomes treatment accelerated wound healing by downregulating inflammatory factor levels and upregulating the M2 macrophage ratio in vivo. Our findings indicated that CB-Treg-derived exosomes could be a promising cell-free therapeutic strategy for diabetic wound healing, partly by targeting monocytes.

Effects of metformin on knee joint capsule fibrosis in a diabetic mouse model.

The antidiabetic agent metformin inhibits fibrosis in various organs. This study aims to elucidate the effects of hyperglycaemia and metformin on knee joint capsule fibrosis in mice. Eight-week-old wild-type (WT) and type 2 diabetic (db/db) mice were divided into four groups without or with metformin treatment (WT met(-/+), Db met(-/+)). Mice received daily intraperitoneal administration of metformin and were killed at 12 and 14 weeks of age. Fibrosis morphology and its related genes and proteins were evaluated. Fibroblasts were extracted from the capsules of 14-week-old mice, and the expression of fibrosis-related genes in response to glucose and metformin was evaluated in vitro. The expression of all fibrosis-related genes was higher in Db met(-) than in WT met(-) and was suppressed by metformin. Increased levels of fibrosis-related genes, posterior capsule thickness, and collagen density were observed in the capsules of db/db mice compared with those in WT mice; these effects were suppressed by metformin. Glucose addition increased fibrosis-related gene expression in both groups of mice in vitro. When glucose was added, metformin inhibited the expression of fibrosis-related genes other than cellular communication network factor 2 (Ccn2) in WT mouse cells. Hyperglycaemia promotes fibrosis in the mouse knee joint capsule, which is inhibited by metformin. These findings can help inform the development of novel strategies for treating knee joint capsule fibrosis.

A lysosomal-targeted and viscosity-ultrasensitive near-infrared fluorescent probe for sensing viscosity in cells and a diabetic mice model

Diabetes, as a metabolic disorder, has been implicated in organ dysfunction, often correlated with aberrant changes in viscosity. Lysosomal viscosity serves as an indicator of the lysosome's condition and activity, as it always varies synchronously with the change of lysosome's positioning, structure, and internal constituents. Diabetes, a condition within the metabolic disease category, has the potential to disrupt organ function due to irregular changes in viscosity. Therefore, early and precise diagnosis of diabetes is crucial for the prevention and management of diabetic conditions. Understanding the correlation between viscosity variations and lysosomal changes in vivo is vitally important for researching associated diseases. In this study, we developed Lyso-V, a near-infrared (NIR) fluorescent probe targeting lysosomes, with ultrasensitivity to viscosity changes. This probe, designed with a donor-π-bridge-acceptor (D-π-A) structure, exhibits a significant increase in NIR fluorescence intensity (approximately 690 times) when responding to viscosity, due to a twisted intramolecular charge transfer (TICT) mechanism. Furthermore, the probe designed specifically for lysosomes, enables the detection of changes in lysosomal viscosity as well as autophagy processes. Notably, through the application of this probe, we have detected an increased viscosity within the pathological model of the diabetic mouse. Moreover, Lyso-V was employed to measure the viscosity in diabetic mice. Owing to the multifaceted nature of the Lyso-V probe, it is anticipated to act as a practical and potent resource for deepening our understanding of the pathophysiological aspects of diabetes and aiding in its early detection.

Uncovering the Role of Anoikis-Related Genes in Modulating Immune Infiltration and Pathogenesis of Diabetic Kidney Disease.

Diabetic kidney disease (DKD) is an intricate complication of diabetes with limited treatment options. Anoikis, a programmed cell death activated by loss of cell anchorage to the extracellular matrix, participated in various physiological and pathological processes. Our study aimed to elucidate the role of anoikis-related genes in DKD pathogenesis. Differentially expressed genes (DEGs) associated with anoikis in DKD were identified. Weighted gene co-expression network analysis (WGCNA) was conducted to identify DKD-correlated modules and assess their functional implications. A diagnostic model for DKD was developed using LASSO regression and Gene set variation analysis (GSVA) was performed for enrichment analysis. Experimental validation was employed to validate the significance of selected genes in the progression of DKD. We identified 10 anoikis-related DEGs involved in key signaling pathways impacting DKD progression. WGCNA highlighted the yellow module's significant enrichment in immune response and regulatory pathways. Correlation analysis further revealed the association between immune infiltration and anoikis-related DEGs. Our LASSO regression-based diagnostic model demonstrated a well-predictive efficacy with seven identified genes. GSVA indicated that gene function in the high-risk group was primarily associated with immune regulation. Further experimental validation using diabetic mouse models and data analysis in the single-cell dataset confirmed the significance of PYCARD and SFN in DKD progression. High glucose stimulation in RAW264.7 and TCMK-1 cells showed significantly increased expression levels of both Pycard and Sfn. Co-expression analysis demonstrated distinct functions of PYCARD and SFN, with KEGG pathway analysis showing significant enrichment in immune regulation and cell proliferation pathway. In conclusion, our study provides valuable insights into the molecular mechanisms involved in DKD pathogenesis, specifically highlighting the role of anoikis-related genes in modulating immune infiltration. These findings suggest that targeting these genes may hold promise for future diagnostic and therapeutic approaches in DKD management.

Branched-Chain Amino Acids Deficiency Promotes Diabetic Neuropathic Pain Through Upregulating LAT1 and Inhibiting Kv1.2 Channel.

Diabetic neuropathic pain (DNP), one of the most common complications of diabetes, is characterized by bilateral symmetrical distal limb pain and substantial morbidity. To compare the differences is aimed at serum metabolite levels between 81 DNP and 73 T2DM patients without neuropathy and found that the levels of branched-chain amino acids (BCAA) are significantly lower in DNP patients than in T2DM patients. In high-fat diet/low-dose streptozotocin (HFD/STZ)-induced T2DM and leptin receptor-deficient diabetic (db/db) mouse models, it is verified that BCAA deficiency aggravated, whereas BCAA supplementation alleviated DNP symptoms. Mechanistically, using a combination of RNA sequencing of mouse dorsal root ganglion (DRG) tissues and label-free quantitative proteomic analysis of cultured cells, it is found that BCAA deficiency activated the expression of L-type amino acid transporter 1 (LAT1) through ATF4, which is reversed by BCAA supplementation. Abnormally upregulated LAT1 reduced Kv1.2 localization to the cell membrane, and inhibited Kv1.2 channels, thereby increasing neuronal excitability and causing neuropathy. Furthermore, intraperitoneal injection of the LAT1 inhibitor, BCH, alleviated DNP symptoms in mice, confirming that BCAA-deficiency-induced LAT1 activation contributes to the onset of DNP. These findings provide fresh insights into the metabolic differences between DNP and T2DM, and the development of approaches for the management of DNP.

Systemic Deletion of ARRDC4 Improves Cardiac Reserve and Exercise Capacity in Diabetes.

Exercise intolerance is an independent predictor of poor prognosis in diabetes. The underlying mechanism of the association between hyperglycemia and exercise intolerance remains undefined. We recently demonstrated that the interaction between ARRDC4 (arrestin domain-containing protein 4) and GLUT1 (glucose transporter 1) regulates cardiac metabolism. To determine whether this mechanism broadly impacts diabetic complications, we investigated the role of ARRDC4 in the pathogenesis of diabetic cardiac/skeletal myopathy using cellular and animal models. High glucose promoted translocation of MondoA into the nucleus, which upregulated Arrdc4 transcriptional expression, increased lysosomal GLUT1 trafficking, and blocked glucose transport in cardiomyocytes, forming a feedback mechanism. This role of ARRDC4 was confirmed in human muscular cells from type 2 diabetic patients. Prolonged hyperglycemia upregulated myocardial Arrdc4 expression in multiple types of mouse models of diabetes. We analyzed hyperglycemia-induced cardiac and skeletal muscle abnormalities in insulin-deficient mice. Hyperglycemia increased advanced glycation end-products and elicited oxidative and endoplasmic reticulum stress leading to apoptosis in the heart and peripheral muscle. Deletion of Arrdc4 augmented tissue glucose transport and mitochondrial respiration, protecting the heart and muscle from tissue damage. Stress hemodynamic analysis and treadmill exhaustion test uncovered that Arrdc4-knockout mice had greater cardiac inotropic/chronotropic reserve with higher exercise endurance than wild-type animals under diabetes. While multiple organs were involved in the mechanism, cardiac-specific overexpression using an adenoassociated virus suggests that high levels of myocardial ARRDC4 have the potential to contribute to exercise intolerance by interfering with cardiac metabolism through its interaction with GLUT1 in diabetes. Importantly, the ARRDC4 mutation mouse line exhibited greater exercise tolerance, showing the potential therapeutic impact on diabetic cardiomyopathy by disrupting the interaction between ARRDC4 and GLUT1. ARRDC4 regulates hyperglycemia-induced toxicities toward cardiac and skeletal muscle, revealing a new molecular framework that connects hyperglycemia to cardiac/skeletal myopathy to exercise intolerance.

YAP1-mediated dysregulation of ACE-ACE2 activity augments cardiac fibrosis upon induction of hyperglycemic stress

BackgroundDiabetic stress acts on the cardiac tissue to induce cardiac hypertrophy and fibrosis. Diabetes induced activated renin angiotensin system (RAS) has been reported to play a critical role in mediating cardiac hypertrophy and fibrosis. Angiotensin converting enzyme (ACE) in producing Angiotensin-II, promotes cardiomyocyte hypertrophy and fibrotic damage. ACE2, a recently discovered molecule structurally homologous to ACE, has been reported to be beneficial in reducing the effect of RAS driven pathologies. MethodsIn vivo diabetic mouse model was used and co-labelling immunostaining assay have been performed to analyse the fibrotic remodeling and involvement of associated target signaling molecules in mouse heart tissue. For in vitro analyses, qPCR and western blot experiments were performed in different groups for RNA and protein expression analyses. ResultsFibrosis markers were observed to be upregulated in the diabetic mouse heart tissue as well as in high glucose treated fibroblast and cardiomyocyte cells. Hyperglycemia induced overexpression of YAP1 leads to increased expression of β-catenin (CTNNB1) and ACE with downregulated ACE2 expression. The differential expression of ACE/ACE2 promotes TGFB1-SMAD2/3 pathway in the hyperglycemic cardiomyocyte and fibroblast resulting in increased cardiac fibrotic remodeling. ConclusionIn the following study, we have reported YAP1 modulates the RAS signaling pathway by inducing ACE and inhibiting ACE2 activity to augment cardiomyocyte hypertrophy and fibrosis in hyperglycemic condition. Furthermore, we have shown that hyperglycemia induced dysregulation of ACE-ACE2 activity by YAP1 promotes cardiac fibrosis through β-catenin/TGFB1 dependent pathway.

Semaglutide outperforms insulin in restoring neutrophil function against implant-related infection in diabetic and obese mice: experimental research.

Bone and joint infections (BJI) are a significant complication after arthroplasty and fracture fixation, particularly challenging in patients with type 2 diabetes mellitus (T2DM) and obesity. Semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), have shown efficacy in managing T2DM and obesity. However, its impact on BJI risk and neutrophil function remains unclear. To investigate whether preoperative semaglutide treatment (1) reduces the risk of BJI in diabetic and obese mice undergoing intra-articular implants, and (2) outperforms insulin in restoring neutrophil function to mitigate implant-related infection. A C57BL/6 mouse model of T2DM/obesity was induced using a high-fat diet (HFD) for 12 weeks. Mice received preoperative insulin or semaglutide therapy for 1-28 days. BJI risk was assessed using an intraarticular-implant model challenged with S. aureus or E. coli. Neutrophil function was evaluated through bactericidal activity, superoxide production, and migration ability. Semaglutide treatment led to a significant and sustained reduction in body weight and improved glucose tolerance in HFD mice. Both insulin and semaglutide therapies significantly reduced BJI risk, with semaglutide showing a more pronounced effect over time. Semaglutide therapy also enhanced neutrophil bactericidal activity, superoxide production, and migration ability compared to insulin therapy. Preoperative semaglutide treatment effectively reduces BJI risk and improves neutrophil function in diabetic and obese mouse models. These findings suggest that semaglutide may be a promising pharmacological intervention to mitigate infection risk in orthopedic patients with T2DM or obesity.

Network approach reveals preferential T-cell and macrophage association with α-linked β-cells in early stage of insulitis in NOD mice.

One of the challenges in studying islet inflammation-insulitis-is that it is a transient phenomenon. Traditional reporting of the insulitis progression is based on cumulative, donor-averaged values of leucocyte density in the vicinity of pancreatic islets, that hinder intra- and inter-islet heterogeneity of disease progression. Here, we aimed to understand why insulitis is non-uniform, often with peri-insulitis lesions formed on one side of an islet. To achieve this, we demonstrated the applicability of network theory in detangling intra-islet multi-cellular interactions during insulitis. Specifically, we asked the question "What is unique about regions of the islet that interact with immune cells first". This study utilized the non-obese diabetic mouse model of type one diabetes and examined the interplay among α-, β-, T-cells, myeloid cells, and macrophages in pancreatic islets during the progression of insulitis. Disease evolution was tracked based on the T/β cell ratio in individual islets. In the early stage, we found that immune cells are preferentially interacting with α-cell-rich regions of an islet. At the islet periphery α-linked β-cells were found to be targeted significantly more compared to those without α-cell neighbors. Additionally, network analysis revealed increased T-myeloid, and T-macrophage interactions with all β-cells.

Specialized pro-resolution mediators in the bladder: effects of resolvin E1 on diabetic bladder dysfunction in the type 1 diabetic male Akita mouse model

BackgroundOne of the most common, but least studied, diabetic complication is diabetic bladder dysfunction. Current therapies include glucose control and symptom-based interventions. However, efficacy of these therapies is mixed and often have undesirable side effects. Diabetes is now known to be a chronic inflammatory disease. Specialized pro-resolving mediators are a class of compounds that promote the resolution of inflammation and have been shown to be effective in treating chronic inflammatory conditions. In this study we examine the ability of resolvin E1 to improve signs of diabetic bladder dysfunction.MethodsMale Akita mice (Type 1 diabetic) develop hyperglycemia at 4 weeks and signs of bladder underactivity by 15 weeks. Starting at 15 weeks, mice were given one or two weeks of daily resolvin E1 and compared to age-matched wild type and untreated Akita mice.ResultsResolvin E1 did not affect diabetic blood glucose after one week, although there was a slight decrease after two weeks. Diabetes decreased body weight and increased bladder weights and this was not affected by resolvin E1. Evan’s blue dye extravasation (an indirect index of inflammation) was dramatically suppressed after one week of resolvin E1 treatment, but, surprisingly, had returned to diabetic levels after two weeks of treatment. Using cystometry, untreated Akita mice showed signs of underactivity (increased void volumes and intercontraction intervals). One week of resolvin E1treatment restored these cystometric findings back to control levels. After two weeks of treatment, cystometric changes were changed from controls but still significantly different from untreated levels, indicating a durable treatment effect even in the presence of increased inflammation at 2 weeks.ConclusionsResolvin E1 has a beneficial effect on diabetic bladder dysfunction in the type 1 diabetic male Akita mouse model.

ENAMPT is a novel therapeutic target for mitigation of coronary microvascular disease in type 2 diabetes

Aims/hypothesisIndividuals with diabetes are at high risk of cardiovascular complications, which significantly increase morbidity/mortality. Coronary microvascular disease (CMD) is recognised as a critical contributor to the increased cardiac mortality observed in people with diabetes. Therefore, there is an urgent need for treatments that are specific to CMD. eNAMPT (extracellular nicotinamide phosphoribosyltransferase) is a damage-associated molecular pattern and TLR4 ligand, whose plasma levels are elevated in people with diabetes. This study was thus designed to investigate the pathogenic role of intracellular nicotinamide phosphoribosyltransferase (iNAMPT) and eNAMPT in promoting the development of CMD in a preclinical murine model of type 2 diabetes.MethodsAn inducible type 2 diabetic mouse model was generated by a single injection of low-dose streptozocin (75 mg/kg, i.p.) combined with a high-fat diet for 16 weeks. The in vivo effects of i/eNAMPT inhibition on cardiac endothelial cell (CEC) function were evaluated by using Nampt+/− heterozygous mice, chronic administration of eNAMPT-neutralising monoclonal antibody (mAb) or use of an NAMPT enzymatic inhibitor (FK866).ResultsAs expected, diabetic wild-type mice exhibited significantly lower coronary flow velocity reserve (CFVR), a determinant of coronary microvascular function, compared with control wild-type mice. eNAMPT plasma levels or expression in CECs were significantly greater in diabetic mice than in control mice. Furthermore, in comparison with diabetic wild-type mice, diabetic Nampt+/− heterozygous mice showed markedly improved CFVR, accompanied by increased left ventricular capillary density and augmented endothelium-dependent relaxation (EDR) in the coronary artery. NAMPT inhibition by FK866 or an eNAMPT-neutralising mAb significantly increased CFVR in diabetic mice. Furthermore, administration of the eNAMPT mAb upregulated expression of angiogenesis- and EDR-related genes in CECs from diabetic mice. Treatment with either eNAMPT or NAD+ significantly decreased CEC migration and reduced EDR in coronary arteries, partly linked to increased production of mitochondrial reactive oxygen species.Conclusions/interpretationThese data indicate that increased i/eNAMPT expression contributes to the development of diabetic coronary microvascular dysfunction, and provide compelling support for eNAMPT inhibition as a novel and effective therapeutic strategy for CMD in diabetes.Graphical

Application of Bletilla striata polysaccharide hydrogel for wound healing among in diabetes

Diabetes has become an increasingly serious global health crisis. Long-term hyperglycemia can lead to vascular and neurological disorders, thus deterring wound healing. Therefore, exploring treatment modalities for wounds in individuals with diabetes is clinically significant. Bletilla striata polysaccharide and bioactive natural polymers carbomer 940 and carboxymethyl chitosan (CMC) are cross-linked to form the Bletilla striata polysaccharide hydrogel (named CCHG/BSP). Upon characterization, we found that the hydrogel has a porous structure and good mechanical and moisture retention properties. A hemolysis test revealed that the hydrogel had high safety. Furthermore, the hydrogel effectively promoted proliferation and migration in mouse L929 fibroblasts. In back wounds inflicted in a streptozotocin-induced mouse model of diabetes, the CCHG/BSP hydrogel significantly promoted wound healing. Hematoxylin-eosin, Masson’s trichrome, and immunohistochemical staining of tissues around the wound suggest that the mechanism underlying wound healing in diabetes may involve the promotion of angiogenesis, regulation of inflammation, and promotion of collagen regeneration. This provides a foundation for studies on and the development of new BSP pharmacotherapeutic products and the clinical application of its hydrogel dressing, and provide novel avenues for treating wounds in individuals with diabetes.

Exploring butyrylcholinesterase expression in living cells and diabetic mouse models using a fluorescent probe with near-infrared excitation and emission maxima

Butyrylcholinesterase (BChE), as a member of the cholinesterase family, is widely expressed in various tissues and cell types. Abnormal activity levels of BChE in organ systems or cells are usually associated with diseases. Therefore, developing effective methods for monitoring the distribution and activity of BChE in vivo is significant for exploring the physiological effects of BChE in organisms and improving prophylaxis, diagnosis or therapy of diseases. In this study, a dihydroxanthene-derived fluorescent probe CHQ-B with near-infrared (NIR) excitation and emission maxima was developed for visualizing endogenous BChE in vivo. This probe exhibits superior selectivity and sensitivity towards BChE, as well as low cytotoxicity and good biocompatibility to biosamples. Furthermore, efficient and robust fluorescence imaging of the distribution and activity of BChE in diabetic mouse models confirmed the high expression of BChE induced by diabetes. Results of experiments demonstrated that CHQ-B is a promising fluorescence imaging tool for exploring butyrylcholinesterase expression in organisms during researches of relationships between BChE expression and various diseases.

Anti-inflammatory PEGylated bilirubin microneedle patch for diabetes treatment

The long-term hyperglycemic environment could easily cause chronic metabolic inflammation with physiological disorders, exacerbate inflammatory cytokine storms, increase the risk of patients contracting other complications. Thus, to develop glucose-responsive insulin delivery microneedles with anti-inflammatory is of much importance. Herein, a novel in-situ H2O2-sensitive insulin delivery microneedle array patch was constructed for the intelligent management of blood glucose in diabetics, which was integrated with nanoparticles (NPs) to achieve synergistic enhancement of anti-inflammatory and antioxidant functions. Specifically, PEGylated bilirubin (BR) nanoparticles were loaded with insulin and glucose-sensing element glucose oxidase (GOD), named as I@PEG-BR/GOD NPs, which could release drugs in response to high concentrations of glucose. Moreover, bilirubin with potent antioxidant and anti-inflammatory functions could induce reprogramming macrophages to M2 type polarization, which was much beneficial to inhibit inflammation caused by hyperglycemia. In vivo results demonstrated such in situ H2O2-sensitive insulin delivery microneedle array patch had good anti-inflammatory and antioxidant therapeutic efficacy in a mice model of diabetes. This novel glucose-responsive insulin delivery combined with the anti-inflammatory functions of microneedle patches show great promising for the treatment of diabetes with safe controlled release of insulin.

Targeting PKCα alleviates iron overload in diabetes and hemochromatosis through the inhibition of ferroportin

AbstractFerroportin (Fpn) is the only iron exporter, playing a crucial role in systemic iron homeostasis. Fpn is negatively regulated by its ligand hepcidin, but other potential regulators in physiological and disease conditions remain poorly understood. Diabetes is a metabolic disorder that develops body iron loading with unknown mechanisms. By using diabetic mouse models and human duodenal specimens, we demonstrated that intestinal Fpn expression was increased in diabetes in a hepcidin-independent manner. Protein kinase C (PKC) is hyperactivated in diabetes. We showed that PKCα was required to sustain baseline Fpn expression and diabetes-induced Fpn upregulation in the enterocytes and macrophages. Knockout of PKCα abolished diabetes-associated iron overload. Mechanistically, activation of PKCα increased the exocytotic trafficking of Fpn and decreased the endocytic trafficking of Fpn in the resting state. Hyperactive PKCα also suppressed hepcidin-induced ubiquitination, internalization, and degradation of Fpn. We further observed that iron loading in the enterocytes and macrophages activated PKCα, acting as a novel mechanism to enhance Fpn-dependent iron efflux. Finally, we demonstrated that the loss-of-function of PKCα and pharmacological inhibition of PKC significantly alleviated hereditary hemochromatosis-associated iron overload. Our study has highlighted, to our knowledge, for the first time, that PKCα is an important positive regulator of Fpn and a new target in the control of iron homeostasis.

Soluble antigen arrays provide increased efficacy and safety over free peptides for tolerogenic immunotherapy.

Autoantigen-specific immunotherapy using peptides offers a more targeted approach to treat autoimmune diseases, but clinical implementation has been challenging. We previously showed that multivalent delivery of peptides as soluble antigen arrays (SAgAs) efficiently protects against spontaneous autoimmune diabetes in the non-obese diabetic (NOD) mouse model. Here, we compared the efficacy, safety, and mechanisms of action of SAgAs versus free peptides. SAgAs, but not their corresponding free peptides at equivalent doses, efficiently prevented the development of diabetes. SAgAs increased the frequency of regulatory T cells among peptide-specific T cells or induce their anergy/exhaustion or deletion, depending on the type of SAgA used (hydrolysable (hSAgA) and non-hydrolysable 'click' SAgA (cSAgA)) and duration of treatment, whereas their corresponding free peptides induced a more effector phenotype following delayed clonal expansion. Over time, the peptides induced an IgE-independent anaphylactic reaction, the incidence of which was significantly delayed when peptides were in SAgA form rather than in free form. Moreover, the N-terminal modification of peptides with aminooxy or alkyne linkers, which was needed for grafting onto hyaluronic acid to make hSAgA or cSAgA variants, respectively, influenced their stimulatory potency and safety, with alkyne-functionalized peptides being more potent and less anaphylactogenic than aminooxy-functionalized peptides. Immunologic anaphylaxis occurred in NOD mice in a dose-dependent manner but not in C57BL/6 or BALB/c mice; however, its incidence did not correlate with the level of anti-peptide antibodies. We provide evidence that SAgAs significantly improve the efficacy of peptides to induce tolerance and prevent autoimmune diabetes while at the same time reducing their anaphylactogenic potential.