Increased levels of ligands of Toll-like receptors 2 and 4 in type 1 diabetes

Influence of Maqian essential oil on gut microbiota and immunoresponses in type 1 diabetes: In silico study

Diversity and homeostasis of gut bacterial composition is highly associated with the pathogenesis of insulin dysfunction and type 1 diabetes melittus (T1D), hence emerged in parallel with the activation of autoimmunity. We aimed to study the bioactive potential of essential oil from Zanthoxylum myriacanthum var. pubescens Huang (Maqian) through computational approaches. Twelve chemical constituents derived from Maqian essential oil were docked with selected proteins (i.e., 3pig, 1kho, 7dmq, 4m4d, 2z65, 4glp, and 3fxi) in which are involved in gut microbiota modulation in T1D. Subsequently, the prediction of bioavailability properties of the small molecules were evaluated. Among all chemical constituents, the post-docking interaction analysis demonstrated that α-phellandrene exhibits the strongest binding affinity and induces gut microbiota modulation with β-fructofuranosidase from Bifidobacterium longum. The current result revealed the potential of 3-Carene and α-Pinene in inducing specific changes in gut microbiota downregulating Clostridium perfringens and quenching Leptotrichia shahii respectively. β-Pinene possess exceptionally strong binding affinity that effectively disrupt the interaction between lipopolysaccharide and its cognate receptors, while α-Phellandrene was exhibited the uppermost binding affinity with TLR4/MD2 and could likely target TLR4 stimulating lipopolysaccharide. Our results are the first to report on the gut microbiota modulation effects of α-Phellandrene and β-Phellandrene via actions on LPS binding to CD14 and the TLR4 co-receptor signaling. In conclusion, our findings based on computational approaches, small molecules from Maqian present as promising agents which could regulate inflammatory response and modulate gut microbiota in type 1 diabetes mellitus.

From Gut to Glucose: A Comprehensive Review on Functional Foods and Dietary Interventions for Diabetes Management

BACKGROUND

In the realm of diabetes research, considerable attention has been directed toward elucidating the intricate interplay between the gastrointestinal tract and glucose regulation. The gastrointestinal tract, once exclusively considered for its role in digestion and nutrient assimilation, is presently acknowledged as a multifaceted ecosystem with regulatory supremacy over metabolic homeostasis and glucose metabolism. Recent studies indicate that alterations in the composition and functionality of the gut microbiota could potentially influence the regulation of glucose levels and glucose homeostasis in the body. Dysbiosis, characterized by perturbations in the equilibrium of gut microbial constituents, has been irrevocably linked to an augmented risk of diabetes mellitus (DM). Moreover, research has revealed the potential influence of the gut microbiota on important factors, like inflammation and insulin sensitivity, which are key contributors to the onset and progression of diabetes. The key protagonists implicated in the regulation of glucose encompass the gut bacteria, gut barrier integrity, and the gut-brain axis. A viable approach to enhance glycemic control while concurrently mitigating the burden of comorbidities associated with diabetes resides in the strategic manipulation of the gut environment through adapted dietary practices.

OBJECTIVE

This review aimed to provide a deep understanding of the complex relationship between gut health, glucose metabolism, and diabetes treatment.

CONCLUSION

This study has presented an exhaustive overview of dietary therapies and functional foods that have undergone extensive research to explore their potential advantages in the management of diabetes. It looks into the role of gut health in glucose regulation, discusses the impact of different dietary elements on the course of diabetes, and evaluates how well functional foods can help with glycemic control. Furthermore, it investigates the mechanistic aspects of these therapies, including their influence on insulin sensitivity, β-cell activity, and inflammation. It deliberates on the limitations and potential prospects associated with integrating functional foods into personalized approaches to diabetes care.

The role of toll-like receptors (TLRs) and their therapeutic applications in glomerulonephritis

One of the most important features of innate immunity is the presence of a special group of pattern recognition receptors (PRRs) called toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), resulting in a quick and effective immune response to them. Glomerulonephritis (GN) is one of the most important categories of renal disorders characterized by destructive responses of the immune system to the glomerulus. To date, the association of TLRs as important innate immune system members with GN has been one of the topics that attracted the attention of researchers in this field. However, the exact role of these receptors in the immunopathogenesis of GN has not yet been fully discussed. Therefore, this study aims to overview the role of TLRs in GN and the possibility of using them as a potential therapeutic target.

Disease Duration and Chronic Complications Associate With Immune Activation in Individuals With Longstanding Type 1 Diabetes

CONTEXT

Type 1 diabetes (T1D) is associated with alterations of the immune response which persist even after the autoimmunity aspect is resolved. Clinical factors that cause dysregulation, however, are not fully understood.

OBJECTIVE

To identify clinical factors that affect immune dysregulation in people with longstanding T1D.

DESIGN

In this cross-sectional study, 243 participants with longstanding T1D were recruited between February 2016 and June 2017 at the Radboudumc, the Netherlands. Blood was drawn to determine immune cell phenotype and functionality, as well as circulating inflammatory proteome. Multivariate linear regression was used to determine the association between glycated hemoglobin (HbA1c) levels, duration of diabetes, insulin need, and diabetes complications with inflammation.

RESULTS

HbA1c level is positively associated with circulating inflammatory markers (P < .05), but not with immune cell number and phenotype. Diabetes duration is associated with increased number of circulating immune cells (P < .05), inflammatory proteome (P < .05), and negatively associated with adaptive immune response against Mycobacterium tuberculosis and Rhizopus oryzae (P < .05). Diabetes nephropathy is associated with increased circulating immune cells (P < .05) and inflammatory markers (P < .05).

CONCLUSION

Disease duration and chronic complications associate with persistent alterations in the immune response of individuals with long standing T1D.

Identification and validation of diagnostic biomarkers of coronary artery disease progression in type 1 diabetes via integrated computational and bioinformatics strategies

OBJECTIVE

Our study aimed to identify early peripheral blood diagnostic biomarkers and elucidate the immune mechanisms of coronary artery disease (CAD) progression in patients with type 1 diabetes mellitus (T1DM).

METHODS

Three transcriptome datasets were retrieved from the Gene Expression Omnibus (GEO) database. Gene modules associated with T1DM were selected with weighted gene co-expression network analysis. Differentially expressed genes (DEGs) between CAD and acute myocardial infarction (AMI) peripheral blood tissues were identified using limma. Candidate biomarkers were selected with functional enrichment analysis, node gene selection from a constructed protein-protein interaction (PPI) network, and 3 machine learning algorithms. Candidate expression was compared, and the receiver operating characteristic curve (ROC) and nomogram were constructed. Immune cell infiltration was assessed with the CIBERSORT algorithm.

RESULTS

A total of 1283 genes comprising 2 modules were detected as the most associated with T1DM. In addition, 451 DEGs related to CAD progression were identified. Among them, 182 were common to both diseases and mainly enriched in immune and inflammatory response regulation. The PPI network yielded 30 top node genes, and 6 were selected using the 3 machine learning algorithms. Upon validation, 4 genes (TLR2, CLEC4D, IL1R2, and NLRC4) were recognized as diagnostic biomarkers with the area under the curve (AUC) > 0.7. All 4 genes were positively correlated with neutrophils in patients with AMI.

CONCLUSION

We identified 4 peripheral blood biomarkers and provided a nomogram for early diagnosing CAD progression to AMI in patients with T1DM. The biomarkers were positively associated with neutrophils, indicating potential therapeutic targets.

Silencing TLR4 using an ultrasound-targeted microbubble destruction-based shRNA system reduces ischemia-induced seizures in hyperglycemic rats

The toll-like receptor 4 (TLR4) pathway is involved in seizures. We investigated whether ultrasound-targeted microbubble destruction (UTMD)-mediated delivery of short hairpin RNA (shRNA) targeting the TLR4 gene (shRNA-TLR4) can reduce ischemia-induced seizures in rats with hyperglycemia. A total of 100 male Wistar rats were randomly assigned to five groups: (1) Sham; (2) normal saline (NS); (3) shRNA-TLR4, where rats were injected with shRNA-TLR4; (4) shRNA-TLR4 + US, where rats were injected with shRNA-TLR4 followed by ultrasound (US) irradiation; and (5) shRNA-TLR4 + microbubbles (MBs) + US, where rats were injected with shRNA-TLR4 mixed with MBs followed by US irradiation. Western blot and immunohistochemical staining were used to measure TLR4-positive cells. Half of the rats in the NS group developed tonic-clonic seizures, and TLR4 expression in the CA3 region of the hippocampus was increased in these rats. In addition, the NS group showed an increased number of TLR4-positive cells compared with the Sham group, while there was a decreased number of TLR4-positive cells in the shRNA, shRNA + US, and shRNA + MBs + US groups. Our findings indicate that the TLR4 pathway is involved in the pathogenesis of ischemia-induced seizures in hyperglycemic rats and that UTMD technology may be a promising strategy to treat brain diseases.

Role of gut microbiota in the pathogenesis and treatment of diabetes mullites: Advanced research-based review

Gut microbiota plays an important role in the proper functioning of human organisms, while its dysbiosis is associated with disease in various body organs. Diabetes mellitus (DM) is a set of heterogeneous metabolic diseases characterized by hyperglycemia caused by direct or indirect insulin deficiency. There is growing evidence that gut microbiota dysbiosis is closely linked to the development of DM. Gut microbiota composition changes in type 1 diabetes mullites (T1DM) and type 2 diabetes mullites (T2DM) patients, which may cause gut leakiness and uncontrolled entry of antigens into the circulation system, triggering an immune response that damages the isle β cells or metabolic disorders. This review summarizes gut microbiota composition in healthy individuals and compares it to diabetes mullites patients. The possible pathogenesis by which gut microbiota dysbiosis causes DM, particularly gut leakiness and changes in gut microbiota metabolites is also discussed. It also presents the process of microbial-based therapies of DM.

Mechanisms Linking COPD to Type 1 and 2 Diabetes Mellitus: Is There a Relationship between Diabetes and COPD?

Chronic obstructive pulmonary disease (COPD) patients frequently suffer from multiple comorbidities, resulting in poor outcomes for these patients. Diabetes is observed at a higher frequency in COPD patients than in the general population. Both type 1 and 2 diabetes mellitus are associated with pulmonary complications, and similar therapeutic strategies are proposed to treat these conditions. Epidemiological studies and disease models have increased our knowledge of these clinical associations. Several recent genome-wide association studies have identified positive genetic correlations between lung function and obesity, possibly due to alterations in genes linked to cell proliferation; embryo, skeletal, and tissue development; and regulation of gene expression. These studies suggest that genetic predisposition, in addition to weight gain, can influence lung function. Cigarette smoke exposure can also influence the differential methylation of CpG sites in genes linked to diabetes and COPD, and smoke-related single nucleotide polymorphisms are associated with resting heart rate and coronary artery disease. Despite the vast literature on clinical disease association, little direct mechanistic evidence is currently available demonstrating that either disease influences the progression of the other, but common pharmacological approaches could slow the progression of these diseases. Here, we review the clinical and scientific literature to discuss whether mechanisms beyond preexisting conditions, lifestyle, and weight gain contribute to the development of COPD associated with diabetes. Specifically, we outline environmental and genetic confounders linked with these diseases.

Microbiota in health and diseases

The role of microbiota in health and diseases is being highlighted by numerous studies since its discovery. Depending on the localized regions, microbiota can be classified into gut, oral, respiratory, and skin microbiota. The microbial communities are in symbiosis with the host, contributing to homeostasis and regulating immune function. However, microbiota dysbiosis can lead to dysregulation of bodily functions and diseases including cardiovascular diseases (CVDs), cancers, respiratory diseases, etc. In this review, we discuss the current knowledge of how microbiota links to host health or pathogenesis. We first summarize the research of microbiota in healthy conditions, including the gut-brain axis, colonization resistance and immune modulation. Then, we highlight the pathogenesis of microbiota dysbiosis in disease development and progression, primarily associated with dysregulation of community composition, modulation of host immune response, and induction of chronic inflammation. Finally, we introduce the clinical approaches that utilize microbiota for disease treatment, such as microbiota modulation and fecal microbial transplantation.

A study of diabetes-induced erectile dysfunction treated with human umbilical cord mesenchymal stem cells

The present study aimed to assess the value of human umbilical cord mesenchymal stem cells (hUC-MSCs) for the treatment of diabetes-induced erectile dysfunction (DMED). We established a type 1 diabetes model through intra-abdominal streptozotocin injection. After 10 weeks, an apomorphine test was performed to screen the rats for erectile dysfunction (ED). The rats were divided into three groups: normal control group (n = 10), DMED group (n = 9) and DMED+hUC-MSC group (n = 9). After 4 weeks of hUC-MSC therapy, erectile function was evaluated by intracavernous pressure measurements, and penile tissue collagen and smooth muscle were examined by haematoxylin-eosin and Masson's trichrome staining. In addition, western blotting, immunohistochemistry and RT-PCR analysis of TLR4, VEGF and eNOS were performed. The results showed that hUC-MSC treatment restored erectile function (p < .05) and reversed the smooth muscle/collagen ratio changes of DMED rats (p < .05). Furthermore, hUC-MSC treatment inhibited the expression of TLR4 (p < .05) and enhanced VEGF and eNOS expression (p < .05). In conclusion, hUC-MSC treatment restored the erectile function of diabetic rats by inhibiting TLR4, improving corpora cavernosa fibrosis, and increasing VEGF and eNOS expression.

Probiotic normalization of systemic inflammation in siblings of type 1 diabetes patients: an open-label pilot study

The incidence of type 1 diabetes (T1D) has increased, coinciding with lifestyle changes that have likely altered the gut microbiota. Dysbiosis, gut barrier dysfunction, and elevated systemic inflammation consistent with microbial antigen exposure, have been associated with T1D susceptibility and progression. A 6-week, single-arm, open-label pilot trial was conducted to investigate whether daily multi-strain probiotic supplementation could reduce this familial inflammation in 25 unaffected siblings of T1D patients. Probiotic supplementation was well-tolerated as reflected by high participant adherence and no adverse events. Community alpha and beta diversity were not altered between the pre- and post-supplement stool samplings. However, LEfSe analyses identified post-supplement enrichment of the family Lachnospiraceae, producers of the anti-inflammatory short chain fatty acid butyrate. Systemic inflammation was measured by plasma-induced transcription and quantified with a gene ontology-based composite inflammatory index (I.I._com). Post-supplement I.I._com was significantly reduced and pathway analysis predicted inhibition of numerous inflammatory mediators and activation of IL10RA. Subjects with the greatest post-supplement reduction in I.I._com exhibited significantly lower CD4+ CD45RO+ (memory):CD4+ CD45RA+ (naïve) T-cell ratios after supplementation. Post-supplement IL-12p40, IL-13, IL-15, IL-18, CCL2, and CCL24 plasma levels were significantly reduced, while post-supplement butyrate levels trended 1.4-fold higher. Probiotic supplementation may modify T1D susceptibility and progression and warrants further study.

The Role of the Gut Microbiota in the Pathogenesis of Diabetes

Diabetes mellitus is a significant clinical and therapeutic problem because it can lead to serious long-term complications. Its pathogenesis is not fully understood, but there are indications that dysbiosis can play a role in the development of diabetes, or that it appears during the course of the disease. Changes in microbiota composition are observed in both type 1 diabetes (T1D) and type 2 diabetes (T2D) patients. These modifications are associated with pro-inflammation, increased intestinal permeability, endotoxemia, impaired β-cell function and development of insulin resistance. This review summarizes the role of the gut microbiota in healthy individuals and the changes in bacterial composition that can be associated with T1D or T2D. It also presents new developments in diabetes therapy based on influencing the gut microbiota as a promising method to alter the course of diabetes. Moreover, it highlights the lacking data and suggests future directions needed to prove the causal relationship between dysbiosis and diabetes, both T1D and T2D.

Toll-Like Receptors (TLRs) and their potential therapeutic applications in diabetic neuropathy

One of the most common diabetic microvascular complications is diabetic neuropathy (DN). Immune cell infiltration in the peripheral nerve system (PNS), myelin loss, Schwann cell death, and axonal damage are all hallmarks of DN, which is currently believed to be a chronic inflammatory disease. Toll-like receptors (TLRs) are found in various types of nervous system cells, including Schwann cells, microglia, oligodendrocytes, astrocytes, and neurons. Proinflammatory mediators released at the end of TLR signal transduction can trigger an inflammatory response involving the nervous system. Studies on the association between TLRs and DN began as early as 2004. Since then, several studies have been conducted to assess the involvement of TLRs in the pathogenesis of DN. The focus of this review is to give a complete summary of the researches that have been done in this context, as well as an overview of the role of TLRs and their therapeutic applications in DN.

Impaired Innate Immunity in Pediatric Patients Type 1 Diabetes-Focus on Toll-like Receptors Expression

Type 1 diabetes (DM1) is classified as an autoimmune disease. An uncontrolled response of B and T lymphocytes to the body's own tissues develops in the absence of immune tolerance. The main aim of the study was to evaluate the effect of the duration of type 1 diabetes in children on the expression of TLR receptors and the relationship with the parameters of glycemic control in patients. As a result, we showed significant differences in the level of TLR2, TLR4 and TLR9 expression in patients with DM1 in the early stage of the disease and treated chronically compared to the healthy group. Additionally, in this study, we found that the numbers of CD19+ B cells, CD3+ CD4+, CD3+ CD8+ T cells and NK cells are different for newly diagnosed DM1 individuals, patients receiving chronic treatment and for healthy controls, indicating an important role of these cells in killing pancreatic beta cells. Moreover, higher levels of IL-10 in patients with newly diagnosed DM1 have also been found, confirming the reports found in the literature.

Type-I diabetes aggravates post-hemorrhagic stroke cognitive impairment by augmenting oxidative stress and neuroinflammation in mice

Diabetes Mellitus (DM) is a major comorbid condition that increases susceptibility to stroke. Intracerebral hemorrhage (ICH), a devastating type of stroke, accounts for only 13% of the total stroke cases but is associated with higher mortality. Multimorbid models of DM and ischemic stroke have been widely studied; however, fewer pieces of evidence are available on the impact of DM on the outcomes of ICH injury. In this study, we investigated the effect of DM on ICH-induced injury and cognitive impairments. Streptozotocin (STZ) induced type-I DM (T1DM) animal model was used, and experimental ICH was induced by intrastriatal injection of collagenase. Our results demonstrated that DM is associated with a significant increase in hematoma volume and deficits in post-stroke locomotor, sensorimotor, and cognitive behavior in mice. The levels of neuroinflammation, oxidative/nitrosative stress, and glial cell activation were also increased in the diabetic mice following ICH injury. This study provides a better understanding of the influence of DM comorbidity on hemorrhagic stroke outcomes and uncovers the important pathological mechanisms underlying DM-induced exacerbation of ICH injury.

The Role of the Gut Microbiome in Diabetes and Obesity-Related Kidney Disease

Diabetic kidney disease (DKD) is a progressive disorder, which is increasing globally in prevalence due to the increased incidence of obesity and diabetes mellitus. Despite optimal clinical management, a significant number of patients with diabetes develop DKD. Hence, hitherto unrecognized factors are likely to be involved in the initiation and progression of DKD. An extensive number of studies have demonstrated the role of microbiota in health and disease. Dysregulation in the microbiota resulting in a deficiency of short chain fatty acids (SCFAs) such as propionate, acetate, and butyrate, by-products of healthy gut microbiota metabolism, have been demonstrated in obesity, type 1 and type 2 diabetes. However, it is not clear to date whether such changes in the microbiota are causative or merely associated with the diseases. It is also not clear which microbiota have protective effects on humans. Few studies have investigated the centrality of reduced SCFA in DKD development and progression or the potential therapeutic effects of supplemental SCFAs on insulin resistance, inflammation, and metabolic changes. SCFA receptors are expressed in the kidneys, and emerging data have demonstrated that intestinal dysbiosis activates the renal renin-angiotensin system, which contributes to the development of DKD. In this review, we will summarize the complex relationship between the gut microbiota and the kidney, examine the evidence for the role of gut dysbiosis in diabetes and obesity-related kidney disease, and explore the mechanisms involved. In addition, we will describe the role of potential therapies that modulate the gut microbiota to prevent or reduce kidney disease progression.

Activation of Peripheral Blood Mononuclear Cells and Leptin Secretion: New Potential Role of Interleukin-2 and High Mobility Group Box (HMGB)1

Activation of innate immunity and low-grade inflammation contributes to hyperglycemia and an onset of Type 2 Diabetes Mellitus (T2DM). Interleukin-2 (IL-2), leptin, High Mobility Group Box-1 (HMGB-1), and increased glucose concentrations are mediators of these processes also by modulating peripheral blood mononuclear cells (PBMCs) response. The aim of this study was to investigate if HMGB-1 and IL-2 turn on PBMCs and their leptin secretion. In isolated human PBMCs and their subpopulations from healthy individuals and naïve T2DM patients, leptin release, pro-inflammatory response and Toll-like Receptors (TLRs) activation was measured. After treatment with IL-2 and HMGB1, NK (Natural Killer) have the highest amount of leptin secretion, whilst NK-T have the maximal release in basal conditions. TLR4 (TAK242) and/or TLR2 (TLR2-IgA) inhibitors decreased leptin secretion after IL-2 and HMGB1 treatment. A further non-significant increase in leptin secretion was reported in PBMCs of naive T2DM patients in response to IL-2 and HMGB-1 stimulation. Finally, hyperglycemia or hyperinsulinemia might stimulate leptin secretion from PBMCs. The amount of leptin released from PBMCs after the different treatments was enough to stimulate the secretion of IL-1β from monocytes. Targeting leptin sera levels and secretion from PBMCs could represent a new therapeutic strategy to counteract metabolic diseases such as T2DM.

Interplay between Heat Shock Proteins, Inflammation, and Pain: A promising Therapeutic Approach

Heat Shock Proteins (HSPs) are important molecular chaperones that facilitate many functions of the cells. They also play a pivotal role in cell survival, especially in the presence of stressors, including nutritional deprivation, lack of oxygen, fever, alcohol, inflammation, oxidative stress, heavy metals, as well as conditions that cause injury and necrosis. In the face of a painful stimulus encounter, many factors could be associated with pain that may include nitric oxide, excitatory amino acids, reactive oxygen species (ROS) formation, prostaglandins, and inflammatory cytokines. One influential factor affecting pain reduction is the expression of HSPs that act as a ROS scavenger, regulate the inflammatory cytokines, and reduce pain responses subsequently. Hence, we assembled information on the painkilling attributes of HSPs. In this field of research, new painkillers could be developed by targetting HSPs to alleviate pain and widen our grasp of pain in pathological conditions and neurological diseases.

Ipragliflozin Ameliorates Diabetic Nephropathy Associated with Perirenal Adipose Expansion in Mice

Sodium glucose cotransporter-2 (SGLT2) inhibitors inhibit the development of diabetic nephropathy (DN). We determined whether changes in perirenal fat (PRAT) by a SGLT2 inhibitor ipragliflozin (Ipra) contribute to the suppression of DN development. High-fat diet (HFD)-fed mice were used as a DN model and were treated with or without Ipra for 6 weeks. Ipra treatment reduced urinary albumin excretion (UAE) and glomerular hypertrophy in HFD-fed mice. In the PRAT of Ipra-treated mice, adipocyte size was increased, and inflammation, fibrosis, and adipocyte death were suppressed. In conditioned medium made from PRAT (PRAT-CM) of Ipra-treated mice, the concentration of leptin was significantly lower than PRAT-CM of mice without Ipra treatment. Serum leptin concentration in renal vein positively correlated with UAE. PRAT-CM from HFD-fed mice showed greater cell proliferation signaling in mouse glomerular endothelial cells (GECs) than PRAT-CM from standard diet-fed mice via p38MAPK and leptin-dependent pathways, whose effects were significantly attenuated in PRAT-CM from Ipra-treated mice. These findings suggest that Ipra-induced PRAT expansion may play an important role in the improvement of DN in HFD-fed mice. In vitro experiments suggest that reduced PRAT-derived leptin by Ipra could inhibit GECs proliferation, possibly contributing to the suppression of DN development.

The Impact of Insulin Resistance on Cardiovascular Control During Exercise in Diabetes

Patients with diabetes display heightened blood pressure response to exercise, but the underlying mechanism remains to be elucidated. There is no direct evidence that insulin resistance (hyperinsulinemia or hyperglycemia) impacts neural cardiovascular control during exercise. We propose a novel paradigm in which hyperinsulinemia or hyperglycemia significantly influences neural regulatory pathways controlling the circulation during exercise in diabetes.

Age-dependent messenger RNA expression of toll-like receptor 4 and intercellular adhesion molecule-1 in peripheral blood mononuclear cells

BACKGROUND

Inflammation plays an important role in the ageing process in which monocytes/macrophages are important players. Intercellular adhesion molecule-1 (ICAM-1), tumour necrosis factor-α (TNF-α) and Toll-like receptor 4 (TLR4) are well-known inflammatory markers. This study aimed to investigate the relationship between age and the expression and correlation of ICAM-1, TNF-α and TLR4 mRNA in peripheral blood mononuclear cells (PBMCs).

METHODS

A total of 239 participants were recruited in a medical centre in Taiwan. The mRNA isolated from the PBMCs was used to determine the levels of ICAM-1, TNF-α and TLR4 mRNAs with real-time polymerase chain reaction (PCR). The propensity-matched analysis was also applied for subgroup analysis.

RESULTS

When compared 189 older adults (≧65 years) to 50 younger adults (<65 years), the ICAM-1, TNF-α and TLR4 mRNA levels in PBMCs were significantly higher in older adults (2.00 ± 0.72 vs 0.87 ± 0.34 for ICAM-1, 2.32 ± 0.69 vs 1.15 ± 0.44 for TNF-α and 1.56 ± 0.47 vs 1.05 ± 0.51 for TLR4, and all P < .0001). Also, both age and TLR4 were independent factors affecting mononuclear cell ICAM-1 in the multiple linear regression analysis (P < .0001).

CONCLUSION

The mRNA levels of ICAM-1 and TLR4 in PBMCs are higher in older adults than those in younger adults. TLR4 is an independent factor affecting ICAM-1 expression in PBMCs, especially in older adults. This may suggest that ICAM-1 and TLR4 in PBMCs are potential biomarkers and their relationship may shed some light on the ageing process.

The role of inflammation in diabetic kidney disease

Diabetic kidney disease (DKD) has been the leading cause of chronic kidney disease for over 20 years. Yet, over these two decades, the clinical approach to this condition has not much improved beyond the administration of glucose-lowering agents, renin-angiotensin-aldosterone system blockers for blood pressure control, and lipid-lowering agents. The proportion of diabetic patients who develop DKD and progress to end-stage renal disease has remained nearly the same. This unmet need for DKD treatment is caused by the complex pathophysiology of DKD, and the difficulty of translating treatment from bench to bed, which further adds to the growing argument that DKD is not a homogeneous disease. To better capture the full spectrum of DKD in our design of treatment regimens, we need improved diagnostic tools that can better distinguish the subgroups within the condition. For instance, DKD is typically placed in the broad category of a non-inflammatory kidney disease. However, genome-wide transcriptome analysis studies consistently indicate the inflammatory signaling pathway activation in DKD. This review will utilize human data in discussing the potential for redefining the role of inflammation in DKD. We also comment on the therapeutic potential of targeted anti-inflammatory therapy for DKD.

Valproic Acid Suppresses Autoimmune Recurrence and Allograft Rejection in Islet Transplantation through Induction of the Differentiation of Regulatory T Cells and Can Be Used in Cell Therapy for Type 1 Diabetes

Type 1 diabetes mellitus (T1D) results from the destruction of insulin-producing β cells in the islet of the pancreas by lymphocytes. Non-obese diabetic (NOD) mouse is an animal model frequently used for this disease. It has been considered that T1D is a T cell-mediated autoimmune disease. Both CD4+ and CD8+ T cells are highly responsible for the destruction of β cells within the pancreatic islets of Langerhans. Previous studies have revealed that regulatory T (Treg) cells play a critical role in the homeostasis of the immune system as well as immune tolerance to autoantigens, thereby preventing autoimmunity. Valproic acid (VPA), a branched short-chain fatty acid, is widely used as an antiepileptic drug and a mood stabilizer. Previous reports have demonstrated that VPA treatment decreases the incidence and severity of collagen-induced arthritis and experimental autoimmune neuritis by increasing the population of Treg cells in these mouse disease models. Given the effect of VPA in the induction of Treg cells’ population, we evaluated the therapeutic potential and the protective mechanism of VPA treatment in the suppression of graft autoimmune rejection and immune recurrence in syngeneic or allogenic islet transplantation mouse models. In our study, we found that the treatment of VPA increased the expression of forkhead box P3 (FOXP3), which is a critical transcription factor that controls Treg cells’ development and function. Our data revealed that 400 mg/kg VPA treatment in recipients effectively prolonged the survival of syngeneic and allogenic islet grafts. The percentage of Treg cells in splenocytes increased in VPA-treated recipients. We also proved that adoptive transfer of VPA-induced Tregs to the transplanted recipients effectively prolonged the survival of islet grafts. The results of this study provide evidence of the therapeutic potential and the underlying mechanism of VPA treatment in syngeneic islet transplantation for T1D. It also provides experimental evidence for cell therapy by adoptive transferring of in vitro VPA-induced Tregs for the suppression of autoimmune recurrence.

High-mobility group box-1 promotes vascular calcification in diabetic mice via endoplasmic reticulum stress

Several studies reported the role of endoplasmic reticulum stress (ERS) in vascular calcification. High-mobility group box-1 (HMGB-1) plays a substantial role in diabetes and its complications. However, relatively little information is available regarding the association between HMGB-1 and calcification, and the underlying mechanism has still remained elusive. Therefore, in the present study, we attempted to indicate whether HMGB-1 could promote vascular calcification via ERS in diabetes. After induction of diabetes by Streptozotocin (STZ), mice were treated with glycyrrhizin (Gly) or 4-phenylbutyrate (4-PBA). Mineral deposition was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and calcium assay. In cell experiments, calcification of vascular smooth muscle cells (VSMCs) was performed with Alizarin Red staining, alkaline phosphatase (ALP) activity and RT-PCR. Expression and location of HMGB-1 in aortic tissue were detected by Western blotting, immunocytochemistry (ICC) and immunohistochemistry (IHC). Diabetic mice demonstrated increased HMGB-1 expression, ERS and vascular calcification. However, inhibition of HMGB-1 with Gly or inhibition of ERS with 4-PBA ameliorated the enhanced vascular calcification and ERS in diabetic mice. In vitro experiments unveiled that inhibition of HMGB-1 attenuated advanced glycation end products (AGEs)-induced ERS in VSMCs. In addition, AGEs promoted translocation and secretion of HMGB-1 in VSMCs, which was reversed by 4-PBA. Moreover, VSMCs exhibited increased mineralization and osteogenic gene expressions in response to HMGB-1 and AGEs. However, inhibition of ERS with 4-PBA partially, although noticeably, attenuated VSMC calcification induced by HMGB-1. Thus, diabetes induced translocation and secretion of HMGB-1 via ERS, which resulted in calcification in diabetic mice and in AGEs-treated VSMCs.

TLR4 knockout ameliorates streptozotocin-induced osteoporosis in a mouse model of diabetes

Type 1 diabetes mellitus (T1DM) is characterized by hyperglycemia manifesting as insufficient insulin. Toll-like receptor-4 (TLR4) has been implicated in diabetic osteoporosis. We established streptozotocin (STZ)-induced diabetic mouse model and examined the relevant osteoporosis factors in different experimental groups, the WT-CON group, WT-STZ group, KO-CON group and KO-STZ group, respectively. No obvious protection of TLR4 deletion was shown in mice with diabetes. There was no obvious difference in the body weight or blood glucose concentration between WT-STZ group and KO-STZ group. However, TLR4 deletion reduced the receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation. Furthermore, TLR4 knockout attenuated STZ-induced diabetic osteoporosis via inhibiting osteoblasts and pre-inflammation factors mediated by the NF-κB pathway. TLR4 deletion ameliorated STZ-induced diabetic osteoporosis in mice, and TLR4 may be used as a potential therapeutic target for the treatment of diabetic osteoporosis.

Patterns of Toll-Like Receptor Expressions and Inflammatory Cytokine Levels and Their Implications in the Progress of Insulin Resistance and Diabetic Nephropathy in Type 2 Diabetic Patients

Background: Diabetic nephropathy (DNP) is a type 2 diabetes mellitus (T2DM) chronic complication, which is the largest single cause of end-stage kidney disease. There is an increasing evidence of the role of inflammation and Toll-like receptors (TLRs) as part of innate immune system in its development and progression. In addition, Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) downward signaling causes the production of proinflammatory cytokines, which can induce insulin (INS) resistance in T2DM.

Objective: The goal of this study was to estimate the expression of TLRs (TLR2 and TLR4) in relation to inflammation and INS resistance in nephrotic type 2 diabetic patients with or without renal failure and to discuss the role of these TLRs in DNP progression.

Patients and Methods: In this study, blood samples were obtained from type 2 diabetic patients with or without renal failure, and patients with non-diabetic renal failure were compared to healthy controls. All participants were tested for analysis of fasting plasma glucose and serum insulin, kidney function tests, C-reactive protein (CRP), and proinflammatory cytokines, including tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and interleukin 6 (IL-6) as well as expression of TLR2 and TLR4 in peripheral blood (PB). Statistical analysis of data was done by using SPSS.

Results: Diabetic patients with renal failure exhibited significant increase in TLR2, TLR4 mRNA expression in PB in comparison with normal subjects, diabetic patients without renal failure and non-diabetic patients with renal failure. Both diabetic patients with or without kidney failure and non-diabetic patients with renal failure had increased TLR2 and TLR4 mRNA expression in association with increased levels of proinflammatory cytokines (TNF-α, IFN-γ, and IL-6) compared to normal subjects. The diabetic patients with kidney failure exhibited the highest elevation of TLRs, Th1 cytokines and CRP in association the highest record of insulin resistance.

Conclusion: Toll-like receptor 2 and Toll-like receptor 4 increased expression and Th2 cytokines may have an important role in the progression of DNP and deteriorations in insulin resistance in type 2 diabetic patients. Therefore, TLR2 and TLR4 may be a promising therapeutic target to prevent or retard DNP in type 2 diabetic patients.

Expression profiles and potential corneal epithelial wound healing regulation targets of high-mobility group box 1 in diabetic mice

As a damage-associated molecular pattern molecule, high-mobility group box 1 protein (HMGB1) is involved in diabetes and its complications. However, the role of HMGB1 in diabetic keratopathy is not yet understood. The purpose of this study was to investigate the potential roles of HMGB1 in the development of diabetic keratopathy as well as potential strategies to block HMGB1 in order to prompt epithelial wound healing and nerve regeneration in diabetic corneas. The results demonstrated that diabetic keratopathy developed in mice over the duration of the diabetic condition with typical symptoms, including damaged ocular surfaces and corneal nerves. The diabetic corneas had significantly increased protein expression levels of HMGB1 and its receptors-the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4)-compared to the age-matched normal corneas (P < 0.05). Corneal HMGB1 levels significantly increased during the corneal wound healing process of the diabetic mice, peaking on the first day after the wound was created and then decreasing to the unwounded level on the seventh day. Exogenous HMGB1 peptide significantly retarded wound and nerve healing, while glycyrrhizin (an HMGB1 inhibitor) significantly prompted wound and nerve healing. Further, the western blot results confirmed that RAGE and TLR4 were also involved in corneal wound and nerve healing. In conclusion, these data showed that HMGB1 and its related receptors are highly involved in the development of diabetic keratopathy. This finding indicates that the blockage of HMGB1 might serve as a strategy to prompt diabetic corneal and nerve wound healing.

Effect of Artemisia absinthium ethanolic extract on oxidative stress markers and the TLR4, S100A4, Bax and Bcl-2 genes expression in the kidney of STZ-induced diabetic rats

OBJECTIVES

The present study was conducted to examine antidiabetic effects of Artemisia absinthium ethanolic extract [A. absinthium] and to investigate its effects on oxidative stress markers and the expression of TLR4, S100A4, Bax and Bcl-2 genes in the kidney of STZ-induced diabetic rats.

METHODS

Thirty six rats (weight 200-250 g) were randomly divided into diabetes and control groups. Induction of diabetes was performed using STZ (55 mg/kg.bw). Biochemical parameters and oxidative stress markers (SOD and MDA) were measured using spectrophotometry after 60 days of treatment. The expression of TLR4, S100A4, Bax and Bcl-2 were analyzed by real-time PCR. One-way analysis of variance (ANOVA) and Bonferroni post hoc test were used to compare the data.

RESULTS

Diabetes significantly impairs the serum fasting blood glucose (FBG), lipid profile, urea, creatinine and albumin. At the end of treatment with A. absinthium extract, these parameters were close to the normal range. The results showed that the A. absinthium extract significantly decreased the kidney expression of TLR4, S100A4, Bax and increased the expression of Bcl-2 and improved oxidative stress markers (SOD and MDA) in the kidney tissues of treated rats. Also, all of these beneficial effects of the A. absinthium were dose-dependent.

CONCLUSIONS

The extract of A. absinthium possesses antidiabetic effects. A. absinthium decreased the expression of TLR4, S100A4, Bax and increased the expression of Bcl-2 and improved oxidative stress. Therefore, this herbal extract can be used as an adjuvant treatment for diabetic complications.

Toll-like Receptor as a Molecular Link between Metabolic Syndrome and Inflammation: A Review

Metabolic Syndrome (MetS) involves a cluster of five conditions, i.e. obesity, hyperglycaemia, hypertension, hypertriglyceridemia and low High-Density Lipoprotein (HDL) cholesterol. All components of MetS share an underlying chronic inflammatory aetiology, manifested by increased levels of pro-inflammatory cytokines. The pathogenic role of inflammation in the development of MetS suggested that toll-like receptor (TLR) activation may trigger MetS. This review summarises the supporting evidence on the interactions between MetS and TLR activation, bridged by the elevation of TLR ligands during MetS. The regulatory circuits mediated by TLR activation, which modulates signal propagation, leading to the state of chronic inflammation, are also discussed. Taken together, TLR activation could be the molecular basis in the development of MetS-induced inflammation.

Harmful effects of high amounts of glucose on the immune system: An updated review

Release and storage of energy can be regulated by the metabolic parameter dependent on the central nervous system. Macrophages are one of the most professional antigen-presenting cells that are formed by the accumulation of dead or damaged cells or in response to the infection, which has the main function of phagocytosis, secretion of cytokines, and presenting antigen to T cells. A proper immune response is needed for the production of effector cytokines along with comprehensive and rapid cell proliferation and growth. Activation of the immune system and immune cells is needed to increase glucose metabolism. When the immune system responds to pathogens, chemokines inform immune cells such as macrophages and T cells to travel to the infected area. Although glucose is vital for the proper function of immune cells and their proliferation, a high amount of glucose may lead to impaired function of the immune system and pathological conditions. However, a suitable amount of glucose is indispensable for the immune system, but its elevated amount leads to excessive proinflammatory cytokines production. In this study, we focused on the master regulatory role of glucose on the immune system.

Immunogenicity Risk Assessment for an Engineered Human Cytokine Analogue Expressed in Different Cell Substrates

The purpose of this article is to illustrate how performance of an immunogenicity risk assessment at the earliest stage of product development can be instructive for critical early decision-making such as choice of host system for expression of a recombinant therapeutic protein and determining the extent of analytical characterization and control of heterogeneity in co- and post-translational modifications. Application of a risk-based approach for a hypothetical recombinant DNA analogue of a human endogenous cytokine with immunomodulatory functions is described. The manner in which both intrinsic and extrinsic factors could interact to influence the relative scale of risk associated with expression in alternative hosts, namely Chinese hamster ovary (CHO) cells, Pichia pastoris, Escherichia coli, or Nicotinia tabacum is considered in relation to the development of the investigational product to treat an autoimmune condition. The article discusses how particular product-related variants (primary amino acid sequence modifications and post-translational glycosylation or other modifications) and process-derived impurities (host cell proteins, endotoxins, beta-glucans) associated with the different expression systems might influence the impact of immunogenicity on overall clinical benefit versus risk for a therapeutic protein candidate that has intrinsic MHC Class II binding potential. The implications of the choice of expression system for relative risk are discussed in relation to specific actions for evaluation and measures for risk mitigation, including use of in silico and in vitro methods to understand intrinsic immunogenic potential relative to incremental risk associated with non-human glycan and protein impurities. Finally, practical guidance on presentation of this information in regulatory submissions to support clinical development is provided.

Analysis of Toll-Like Receptor-2 and 4 Expressions in Peripheral Monocyte Subsets in Patients with Type 1 Diabetes Mellitus

Background: Dysfunction of the peripheral blood monocytes in the form of changes in their proportion, cytokines or pattern-recognition receptors (PRR) expressions may be involved in the pathogenesis of type 1 diabetes mellitus (T1DM). Our aim is to analyze the three monocyte subsets; classical, non-classical and intermediate monocytes and their expression of Toll-like receptors 2 (TLR-2) and 4 (TLR-4) in T1DM patients. Methods: The peripheral blood monocytes of 20 T1DM patients were analyzed by Flow cytometry to measure their count and TLR-2 and TLR-4 expression. Results: T1DM patients had more non-classical and intermediate monocytes, whereas classical monocytes were comparable between patients and control (20 healthy volunteers). Classical, non-classical and intermediate monocytes had no significant correlations with hemoglobin (Hb) A1C in controls, while all subsets showed positive correlations with HbA1C in T1DM. TLR-2 and TLR-4 expression were significantly increased in classical monocytes in patients, especially those with diabetic ketoacidosis (DKA), and both of them showed positive correlations with the duration of T1DM. The expression of TLR-2 inside non-classical monocytes showed a negative correlation with LDL cholesterol and TLR-4/TLR-2 ratio showed positive correlations with the duration of T1DM and negative correlations with total cholesterol. The expression of TLR-2 inside intermediate monocytes showed positive correlations with the duration of T1DM and TLR-4/TLR-2 ratio showed negative correlations with the duration of T1DM Conclusions: The observed changes in both proportions and TLR-2 and TLR-4 expression of monocyte subsets can raise the possible role in the pathogenesis of early stages of T1DM and DKA. Abbreviations APC: allophycocyanin; CBC: complete blood picture; DKA: diabetic acidosis; DM: diabetes mellitus; FITC: fluorescein isothiocyanate; FSC: forward scatter; Hb: haemoglobin; MFI: mean channel fluorescence intensity; PE: phycoerythrin; PRR: pattern-recognition receptors; SPSS: statistical package for the social sciences; SSC: side scatter; T1DM: Type1DM; TLRs: toll-like receptors.

Oral butyrate does not affect innate immunity and islet autoimmunity in individuals with longstanding type 1 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

The pathophysiology of type 1 diabetes has been linked to altered gut microbiota and more specifically to a shortage of intestinal production of the short-chain fatty acid (SCFA) butyrate, which may play key roles in maintaining intestinal epithelial integrity and in human and gut microbial metabolism. Butyrate supplementation can protect against autoimmune diabetes in mouse models. We thus set out to study the effect of oral butyrate vs placebo on glucose regulation and immune variables in human participants with longstanding type 1 diabetes.

METHODS

We administered a daily oral dose of 4 g sodium butyrate or placebo for 1 month to 30 individuals with longstanding type 1 diabetes, without comorbidity or medication use, in a randomised (1:1), controlled, double-blind crossover trial, with a washout period of 1 month in between. Participants were randomly allocated to the 'oral sodium butyrate capsules first' or 'oral placebo capsules first' study arm in blocks of five. The clinical investigator received blinded medication from the clinical trial pharmacy. All participants, people doing measurements or examinations, or people assessing the outcomes were blinded to group assignment. The primary outcome was a change in the innate immune phenotype (monocyte subsets and in vitro cytokine production). Secondary outcomes were changes in blood markers of islet autoimmunity (cell counts, lymphocyte stimulation indices and CD8 quantum dot assays), glucose and lipid metabolism, beta cell function (by mixed-meal test), gut microbiota and faecal SCFA. The data was collected at the Amsterdam University Medical Centers.

RESULTS

All 30 participants were analysed. Faecal butyrate and propionate levels were significantly affected by oral butyrate supplementation and butyrate treatment was safe. However, this modulation of intestinal SCFAs did not result in any significant changes in adaptive or innate immunity, or in any of the other outcome variables. In our discussion, we elaborate on this important discrepancy with previous animal work.

CONCLUSIONS/INTERPRETATION

Oral butyrate supplementation does not significantly affect innate or adaptive immunity in humans with longstanding type 1 diabetes.

TRIAL REGISTRATION

Netherlands Trial Register: NL4832 (www.trialregister.nl).

DATA AVAILABILITY

Raw sequencing data are available in the European Nucleotide Archive repository (https://www.ebi.ac.uk/ena/browse) under study PRJEB30292.

FUNDING

The study was funded by a Le Ducq consortium grant, a CVON grant, a personal ZONMW-VIDI grant and a Dutch Heart Foundation grant.

Skeletal Muscle Reflex-Induced Sympathetic Dysregulation and Sensitization of Muscle Afferents in Type 1 Diabetic Rats

The blood pressure response to exercise is exaggerated in the type 1 diabetes mellitus (T1DM). An overactive exercise pressor reflex (EPR) contributes to the potentiated pressor response. However, the mechanism(s) underlying this abnormal EPR activity remains unclear. This study tested the hypothesis that the heightened blood pressure response to exercise in T1DM is mediated by EPR-induced sympathetic overactivity. Additionally, the study examined whether the single muscle afferents are sensitized by PKC (protein kinase C) activation in this disease. Sprague-Dawley rats were intraperitoneally administered either 50 mg/kg streptozotocin (T1DM) or saline (control). At 1 to 3 weeks after administration, renal sympathetic nerve activity and mean arterial pressure responses to activation of the EPR, mechanoreflex, and metaboreflex were measured in decerebrate animals. Action potential responses to mechanical and chemical stimulation were determined in group IV afferents with pPKCα (phosphorylated-PKCα) levels assessed in dorsal root ganglia. Compared with control, EPR (58±18 versus 96±33%; P<0.05), mechanoreflex (21±13 versus 51±20%; P<0.05), and metaboreflex (40±20 versus 88±39%; P<0.01) activation in T1DM rats evoked significant increases in renal sympathetic nerve activity as well as mean arterial pressure. The response of group IV afferents to mechanical (18±24 versus 61±45 spikes; P<0.01) and chemical (0.3±0.4 versus 1.6±0.8 Hz; P<0.01) stimuli were significantly greater in T1DM than control. T1DM rats showed markedly increased pPKCα levels in dorsal root ganglia compared with control. These data suggest that in T1DM, abnormally muscle reflex-evoked increases in sympathetic activity mediate exaggerations in blood pressure. Further, sensitization of muscle afferents, potentially via PKC activation, may contribute to this abnormal circulatory responsiveness.

Innate immunity in diabetic kidney disease

Increasing evidence suggests that renal inflammation contributes to the pathogenesis and progression of diabetic kidney disease (DKD) and that anti-inflammatory therapies might have renoprotective effects in DKD. Immune cells and resident renal cells that activate innate immunity have critical roles in triggering and sustaining inflammation in this setting. Evidence from clinical and experimental studies suggests that several innate immune pathways have potential roles in the pathogenesis and progression of DKD. Toll-like receptors detect endogenous danger-associated molecular patterns generated during diabetes and induce a sterile tubulointerstitial inflammatory response via the NF-κB signalling pathway. The NLRP3 inflammasome links sensing of metabolic stress in the diabetic kidney to activation of pro-inflammatory cascades via the induction of IL-1β and IL-18. The kallikrein-kinin system promotes inflammatory processes via the generation of bradykinins and the activation of bradykinin receptors, and activation of protease-activated receptors on kidney cells by coagulation enzymes contributes to renal inflammation and fibrosis in DKD. In addition, hyperglycaemia leads to protein glycation and activation of the complement cascade via recognition of glycated proteins by mannan-binding lectin and/or dysfunction of glycated complement regulatory proteins. Data from preclinical studies suggest that targeting these innate immune pathways could lead to novel therapies for DKD.

Toll-like receptor 4 inhibition prevents autoimmune diabetes in NOD mice

TLR4 is a transmembrane receptor of the innate immune system that recognizes LPS from gram-negative bacteria. Its stimulation induces pro-inflammatory responses and modulates adaptive immunity. Our aim is to determine the role of TLR4 in the activation and proliferation of T lymphocytes in the onset of autoimmune diabetes, using the non-obese diabetic (NOD) mouse model. Antigen-specific activation and proliferation of diabetogenic T cells were assessed in vitro by Carboxyfluorescein succinimidyl ester (CFSE) dilution, in presence of vehicle or CLI-095, a cyclohexene derivative that inhibits TLR4 signaling. NOD mice were treated with vehicle or CLI-095 and sacrificed either before or after the onset of autoimmune diabetes. T lymphocyte activation and proliferation were evaluated in treated and control mice. Insulitis was analyzed by histology and diabetes incidence was determined in treated and control mice. Our results demonstrate that TLR4 blockade decreases CD4+ T lymphocyte activation and auto-antigen-specific proliferation both in vitro and in vivo, decreases the infiltrative insulitis and finally prevents the onset of spontaneous diabetes. Taken together, our data demonstrate that TLR4 signaling contributes to the development and maintenance of autoimmune diabetes. The immunomodulatory effect of CLI-095 could be part of a preventive strategy targeting patients at risk for type 1 diabetes.

MiR-885-3p is down-regulated in peripheral blood mononuclear cells from T1D patients and regulates the inflammatory response via targeting TLR4/NF-κB signaling

BACKGROUND

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by the progressive destruction of insulin-production pancreatic β cells. Recently, microRNAs (miRNAs) have emerged as important regulators in T1D. The present study aimed to determine miR-885-3p expression in T1D patients and to examine the effects of miR-885-3p on the inflammatory response in human monocytes.

METHODS

Relevant gene expression levels were determined by a quantitative polymerase chain reaction; western blotting and enzyme-linked immunosorbent assays determined the respective protein levels; and the interaction between miRNA and the downstream targets was evaluated using a luciferase reporter assay.

RESULTS

MiR-885-3p is down-regulated and the levels of pro-inflammatory cytokines are increased in peripheral blood mononuclear cells (PBMCs) from T1D patients compared to healthy controls. MiR-885-3p overexpression suppressed mRNA expression and secreted protein levels of pro-inflammatory cytokines in THP-1. A luciferase reporter assay showed that miR-885-3p directly targeted the 3'-untranslated region of Toll-like receptor 4 (TLR4) and miR-885-3p overexpression down-regulated TLR4 expression in THP-1 cells. The TLR4 mRNA expression level was increased in PBMCs isolated from T1D patients compared to heathy controls. TLR4 overexpression increased the secretion of pro-inflammatory cytokines and enhanced the activity of NF-κB signaling, and also attenuated the inhibitory effects of miR-885-3p overexpression on pro-inflammatory cytokine secretion and the activity of NF-κB signaling in THP-1 cells.

CONCLUSIONS

The present study identified the down-regulation of miR-885-3p and up-regulation of TLR4 in PBMCs isolated from T1D patients. Further mechanistic data demonstrated that miR-885-3p overexpression represses the production of pro-inflammatory cytokines via targeting TLR4/NF-κB signaling in THP-1 cells.

Fucoidan prevent murine autoimmune diabetes via suppression TLR4-signaling pathways, regulation DC/Treg induced immune tolerance and improving gut microecology

Background

This study was to investigate the effect and its possible mechanism of fucoidan on the development of spontaneous autoimmune diabetes in non-obese diabetic (NOD) mice.

Methods

7-week-old NOD mice were randomly divided into three groups: control group, low-dose (300 mg/kg) and high-dose (600 mg/kg) fucoidan-treatment groups. After 5 weeks of treatment, 10 mice per group were randomly selected to be sacrificed after feces collection. The remaining 12 mice per group were fed until 26 weeks of age to assess the incidence of diabetes.

Results

Treatment with fucoidan increased serum insulin level, delayed the onset and decreased the development of diabetes in NOD mice. Fucoidan reduced the levels of strong Th1 proinflammatory cytokines, but induced Th2-bias ed. cytokine response. And dentridic cells (DCs) in fucoidan treatment group were characterized as low expression of MHC class II and CD86 molecules. TLR4 expressions and the downstream molecules in pancreas were down-regulated in fucoidan-treated groups. There were significant differences in the composition of gut flora between NOD control group and fucoidan group. Lactobacillus and Akkermansia were significantly enriched in fucoidan group.

Conclusions

Fucoidan could prevent the development of autoimmune diabetes in NOD mice via regulating DC/Treg induced immune tolerance, improving gut microecology, down-regulating TLR4 signaling pathway, and maintaining pancreatic internal environment.

Systemic exposure to CpG-ODN elicits low-grade inflammation in the retina

Previous studies have reported that topical exposure to the toll-like receptor (TLR) 9 ligand CpG-ODN causes widespread ocular inflammation, including retinal microglial activation and posterior segment inflammation. Here we sought to determine the effects of systemic exposure to CpG-ODN in the retina and whether this inflammatory response was altered with Cx₃cr1 deficiency or hyperglycemia. Male non-diabetic Cx₃cr1^+/gfp and Cx₃cr1^gfp/gfp littermates (normoglycemic controls) and Cx₃cr1^+/gfpIns2^Akitaand Cx₃cr1^gfp/gfpIns2^Akita diabetic mice were injected intraperitoneally with 40 μg CpG-ODN. Immunofluorescence staining was performed 1 week later to assess the expression of MHC Class II and glial fibrillary acidic protein (GFAP), as well as to identify morphological changes to microglia and changes in retinal macrophage cell density. Systemic exposure to CpG-ODN induced the upregulated expression of both GFAP on retinal Müller cells and MHC Class II on the retinal vasculature. Additionally, there was an increased accumulation of macrophages in the subretinal space 1 week after exposure to systemic CpG-ODN as well as characteristic morphological changes to microglia indicative of an activated phenotype. These preliminary studies demonstrate that low-grade inflammatory changes were not enhanced in Cx₃cr1-deficient or diabetic mice, indicating that the inflammatory response to systemic CpG-ODN in the retina is unaltered in the context of Cx₃cr1 deficiency or prolonged hyperglycemia.

BDNF Alleviates Neuroinflammation in the Hippocampus of Type 1 Diabetic Mice via Blocking the Aberrant HMGB1/RAGE/NF-κB Pathway

Diabetes is a systemic disease that can cause brain damage such as synaptic impairments in the hippocampus, which is partly because of neuroinflammation induced by hyperglycemia. Brain-derived neurotrophic factor (BDNF) is essential in modulating neuroplasticity. Its role in anti-inflammation in diabetes is largely unknown. In the present study, we investigated the effects of BDNF overexpression on reducing neuroinflammation and the underlying mechanism in mice with type 1 diabetes induced by streptozotocin (STZ). Animals were stereotactically microinjected in the hippocampus with recombinant adeno-associated virus (AAV) expressing BDNF or EGFP. After virus infection, four groups of mice, the EGFP+STZ, BDNF+STZ, EGFP Control and BDNF Control groups, received STZ or vehicle treatment as indicated. Three weeks later brain tissues were collected. We found that BDNF overexpression in the hippocampus significantly rescued STZ-induced decreases in mRNA and protein expression of two synaptic plasticity markers, spinophilin and synaptophysin. More interestingly, BDNF inhibited hyperglycemia-induced microglial activation and reduced elevated levels of inflammatory factors (TNF-α, IL-6). BDNF blocked the increase in HMGB1 levels and specifically, in levels of one of the HMGB1 receptors, RAGE. Downstream of HMGB1/RAGE, the increase in the protein level of phosphorylated NF-κB was also reversed by BDNF in STZ-treated mice. These results show that BDNF overexpression reduces neuroinflammation in the hippocampus of type 1 diabetic mice and suggest that the HMGB1/RAGE/NF-κB signaling pathway may contribute to alleviation of neuroinflammation by BDNF in diabetic mice.

MicroRNA Post-transcriptional Regulation of the NLRP3 Inflammasome in Immunopathologies

Inflammation has a crucial role in protection against various pathogens. The inflammasome is an intracellular multiprotein signaling complex that is linked to pathogen sensing and initiation of the inflammatory response in physiological and pathological conditions. The most characterized inflammasome is the NLRP3 inflammasome, which is a known sensor of cell stress and is tightly regulated in resting cells. However, altered regulation of the NLRP3 inflammasome is found in several pathological conditions, including autoimmune disease and cancer. NLRP3 expression was shown to be post-transcriptionally regulated and multiple miRNA have been implicated in post-transcriptional regulation of the inflammasome. Therefore, in recent years, miRNA based post-transcriptional control of NLRP3 has become a focus of much research, especially as a potential therapeutic approach. In this review, we provide a summary of the recent investigations on the role of miRNA in the post-transcriptional control of the NLRP3 inflammasome, a key regulator of pro-inflammatory IL-1β and IL-18 cytokine production. Current approaches to targeting the inflammasome product were shown to be an effective treatment for diseases linked to NLRP3 overexpression. Although utilizing NLRP3 targeting miRNAs was shown to be a successful therapeutic approach in several animal models, their therapeutic application in patients remains to be determined.

Effects of a Ganoderma atrum polysaccharide against pancreatic damage in streptozotocin-induced diabetic mice

This study aimed at exploring the role of a Ganoderma atrum polysaccharide (PSG-1) in pancreatic damage in streptozotocin (STZ)-induced type 1 diabetes mellitus (T1DM) mice.

Toll-Like Receptor 2 (TLR-2) Gene Polymorphisms in Type 2 Diabetes Mellitus

Objective

Innate immunity factors are associated with type 2 diabetes (T2DM) and its complications. Therefore, T2DM has been suggested to be an immune-dependent disease. Elevated fasting glucose level and higher concentrations of innate immunity soluble molecules are not only related with insulin resistance, but inflammation is also an important factor in beta cell dysfunction in T2DM. Toll-like receptor 2 (TLR-2), which has an important role in inducing innate immune cells, is thought to have suppressive roles on immune responses in T2DM. We therefore aimed to investigate the possible role of TLR-2 del -196-174 and Arg753Gln variants in T2DM pathogenesis.

Materials and Methods

This study was designed as a case-control study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to genotype the two variants in 100 T2DM patients and 98 age- matched controls.

Results

We found significantly higher frequencies of TLR-2 del -196-174 DD genotype (P=0.003), ID genotype (P=0.009) and D allele (P=0.001) in patients compared with controls. In addition, the II genotype (P=0.001) and the I allele (P=0.003) frequencies were elevated in healthy controls. We did not find any significant differences in frequency distribution for the Arg753Gln variant in study groups.

Conclusion

We suggest that carrying the D allele of the TLR-2 del -196-174 variant may be related as a risk factor for T2DM.

Sensory neuronal sensitisation occurs through HMGB-1-RAGE and TRPV1 in high-glucose conditions

Many potential causes for painful diabetic neuropathy have been proposed including actions of cytokines and growth factors. High mobility group protein B1 (HMGB1) is a RAGE (also known as AGER) agonist whose levels are increased in diabetes and that contributes to pain by modulating peripheral inflammatory responses. HMGB1 enhances nociceptive behaviour in naïve animals through an unknown mechanism. We tested the hypothesis that HMGB1 causes pain through direct neuronal activation of RAGE and alteration of nociceptive neuronal responsiveness. HMGB1 and RAGE expression were increased in skin and primary sensory (dorsal root ganglion, DRG) neurons of diabetic rats at times when pain behaviour was enhanced. Agonist-evoked TRPV1-mediated Ca2+ responses increased in cultured DRG neurons from diabetic rats and in neurons from naïve rats exposed to high glucose concentrations. HMGB1-mediated increases in TRPV1-evoked Ca2+ responses in DRG neurons were RAGE- and PKC-dependent, and this was blocked by co-administration of the growth factor splice variant VEGF-A165b. Pain behaviour and the DRG RAGE expression increases were blocked by VEGF-A165b treatment of diabetic rats in vivo Hence, we conclude that HMGB1-RAGE activation sensitises DRG neurons in vitro, and that VEGF-A165b blocks HMGB-1-RAGE DRG activation, which may contribute to its analgesic properties in vivo.

Epigenetic regulation of Toll-like receptors and its roles in type 1 diabetes

The immune system can be divided into adaptive immunity and innate immunity. Adaptive immunity has been confirmed to be involved in the pathogenesis of autoimmune diseases, including type 1 diabetes (T1D). However, the role of innate immunity in T1D has only been studied recently. T1D is caused by selective autoimmune destruction of pancreatic islet β cells. A series of studies have suggested that TLRs play a critical role in the pathogenesis of T1D. Aberrant TLR signaling will change immune homeostasis and result in immunopathological conditions such as endotoxin shock and autoimmune responses. Thus, TLR signaling pathways are supposed to be strictly and finely regulated. Epigenetics has recently been proven to be a new regulator of TLR expression. DNA methylation, histone modification, and microRNAs are the three main epigenetic modifications. This review will mainly focus on these epigenetic mechanisms of regulation of TLRs and the role of TLRs in the pathogenesis of T1D.

The role of toll-like receptors in diabetic kidney disease

PURPOSE OF REVIEW

Involved in innate immunity, toll-like receptors (TLRs) recognize pathogenic and endogenous ligands. Ligand binding initiates an inflammatory cascade which if sustained leads to fibrosis. This review summarizes the role of TLRs in diabetic kidney disease (DKD) with particular emphasis on TLR2 and TLR4.

RECENT FINDINGS

Collectively, preclinical evidence to date supports the causative role of TLR2 and TLR4 in both type I and type II DKD. The relative importance of each is still unclear. In experimental models, there are increased TLR2 and TLR4 ligands, expression and signalling. Functional studies using inhibitors or knockout animal models confirm causality. Clinical evidence also supports increased ligands and TLR2 and TLR4 expression in diabetes however there are no clinical studies examining whether interruption of these pathways confer renoprotection.

SUMMARY

Preclinical evidence to date supports the role of TLR2 and TLR4 in DKD. It will be useful to examine the value of interrupting these signalling pathways in clinical trials.

Blockade of HMGB1 Attenuates Diabetic Nephropathy in Mice

Activation of TLR2 or TLR4 by endogenous ligands such as high mobility group box 1 (HMGB1) may mediate inflammation causing diabetic kidney injury. We determined whether blockade of HMGB1 signaling by: (1) supra-physiological production of endogenous secretory Receptor for Advanced Glycation End-products (esRAGE), a receptor for HMGB1; (2) administration of HMGB1 A Box, a specific competitive antagonist, would inhibit development of streptozotocin induced diabetic nephropathy (DN). Wild-type diabetic mice developed albuminuria, glomerular injuries, interstitial fibrosis and renal inflammation. Using an adeno-associated virus vector, systemic over-expression of esRAGE afforded significant protection from all parameters. No protection was achieved by a control vector which expressed human serum albumin. Administration of A Box was similarly protective against development of DN. To determine the mechanism(s) of protection, we found that whilst deficiency of TLR2, TLR4 or RAGE afforded partial protection from development of DN, over-expression of esRAGE provided additional protection in TLR2^−/−, modest protection against podocyte damage only in TLR4^−/− and no protection in RAGE^−/− diabetic mice, suggesting the protection provided by esRAGE was primarily through interruption of RAGE and TLR4 pathways. We conclude that strategies to block the interaction between HMGB1 and its receptors may be effective in preventing the development of DN.