Lipopolysaccharide regulated protein expression is only partly impaired in monocytes from patients with type I diabetes

Targeting macrophages with phosphatidylserine-rich liposomes as a potential antigen-specific immunotherapy for type 1 diabetes

Type 1 diabetes (T1D) results from a breakdown in immunological tolerance, with pivotal involvement of antigen-presenting cells. In this context, antigen-specific immunotherapies have been developed to arrest autoimmunity, such as phosphatidylserine (PS)-liposomes. However, the role of certain antigen-presenting cells in immunotherapy, particularly human macrophages (Mφ) in T1D remains elusive. The aim of this study was to determine the role of Mφ in antigen-specific immune tolerance and T1D. To that end, we evaluated Mφ ability to capture apoptotic-body mimicking PS-liposomes in mice and conducted a phenotypic and functional characterisation of four human monocyte-derived Mφ (MoMφ) subpopulations (M0, M1, M2a and M2c) after PS-liposomes uptake. Our findings in mice identified Mφ as the most phagocytic cell subset in the spleen and liver. In humans, while phagocytosis rates were comparable between T1D and control individuals, PS-liposome capture dynamics differed among Mφ subtypes, favouring inflammatory (M1) and deactivated (M2c) Mφ. Notably, high nanoparticle concentrations did not affect macrophage viability. PS-liposome uptake by Mφ induced alterations in membrane molecule expression related to immunoregulation, reduced secretion of IL-6 and IL-12, and diminished autologous T-cell proliferation in the context of autoantigen stimulation. These results underscore the tolerogenic effects of PS-liposomes and emphasize their potential to target human Mφ, providing valuable insights into the mechanism of action of this preclinical immunotherapy.

Type 1 diabetes, its complications, and non-ischemic cardiomyopathy: a mendelian randomization study of European ancestry

BACKGROUND

Type 1 diabetes (T1D) is a significant risk factor for a range of cardiovascular diseases. Nonetheless, the causal relationship between T1D and non-ischemic cardiomyopathy (NICM) remains to be elucidated. Furthermore, the mechanisms responsible for the progression from T1D to NICM have not been definitively characterized.

OBJECTIVE

The aim of this study was to conduct a Mendelian randomization (MR) study to investigate the causal effects of T1D and its complications on the development of NICM. Additionally, this study aimed to conduct a mediation analysis to identify potential mediators within this correlation.

METHODS

Genetic variants were used as instrumental variables for T1D. The summary data for T1D were obtained from two genome-wide association study datasets. The summary data for T1D with complications and NICM were obtained from the Finnish database. Two-sample MR, multivariable MR and mediation MR were conducted in this study.

RESULTS

The study revealed a causal association between T1D, T1D with complications, and NICM (with odds ratios of 1.02, 95% CI 1.01-1.04, p = 1.17e-04 and 1.03, 95% CI 1.01-1.05, p = 3.15e-3). Even after adjusting for confounding factors such as body mass index and hypertension, T1D remained statistically significant (with odds ratio of 1.02, 95% CI 1.01-1.04, p = 1.35e-4). Mediation analysis indicated that monokine induced by gamma interferon may play a mediating role in the pathogenesis of T1D-NICM (mediation effect indicated by odds ratio of 1.005, 95% CI 1.001-1.01, p = 4.9e-2).

CONCLUSION

The study demonstrates a causal relationship between T1D, its complications, and NICM. Additionally, monokine induced by gamma interferon may act as a potential mediator in the pathogenesis of T1D-NICM.

Advancements in Free-Radical Pathologies and an Important Treatment Solution with a Free-Radical Inhibitor

Unsaturated carbon-carbon double bonds particularly at exposed end groups of nonsolid fluids are susceptible to free-radical covalent bonding on one carbon atom creating a new free radical on the opposite carbon atom. Subsequent reactive secondary sequence free-radical polymerization can then continue across extensive carbon-carbon double bonds to form progressively larger molecules with ever-increasing viscosity and eventually produce solids. In a fluid solution when carbon-carbon double bonds are replaced by carbon-carbon single bonds to decrease fluidity, increasing molecular organization can interfere with molecular oxygen (O2) diffusion. During normal eukaryote cellular energy synthesis O2 is required by mitochondria to combine with electrons from the electron transport chain and hydrogen cations from the proton gradient to form water. When O2 is absent during periods of irregular hypoxia in mitochondrial energy synthesis, the generation of excess electrons can develop free radicals or excess protons can produce acid. Free radicals formed by limited O2 can damage lipids and proteins and greatly increase molecular sizes in growing vicious cycles to reduce oxygen availability even more for mitochondria during energy synthesis. Further, at adequate free-radical concentrations a reactive crosslinking unsaturated aldehyde lipid breakdown product can significantly support free-radical polymerization of lipid oils into rubbery gel-like solids and eventually even produce a crystalline lipid peroxidation with the double bond of O2. Most importantly, free-radical inhibitor hydroquinone intended for medical treatments in much pathology such as cancer, atherosclerosis, diabetes, infection/inflammation and also ageing has proven extremely effective in sequestering free radicals to prevent chain-growth reactive secondary sequence polymerization.

Dysregulated Toll-like receptor-induced interleukin-1β and interleukin-6 responses in subjects at risk for the development of type 1 diabetes

We tested the hypothesis that altered Toll-like receptor (TLR) signaling may be involved in early stages of type 1 diabetes (T1D). To do so, we analyzed TLR-induced interleukin (IL)-1β and IL-6 responses in freshly isolated peripheral blood mononuclear cells (PBMNCs) from seropositive compared with seronegative subjects. Similar frequencies of myeloid dendritic cells (mDCs), plasmacytoid DCs (pDCs), and monocytes were observed in seropositive and seronegative subjects. Subjects with autoantibodies had increased proportions of monocytes expressing IL-1β ex vivo. Activating PBMNCs with TLR3, TLR4, or TLR7/8 agonists in vitro led to increased percentages of IL-1β-expressing monocytes and mDCs from seropositive versus seronegative subjects. TLR ligation also resulted in a diminished IL-6 response in seropositive individuals as lower frequencies of IL-6-expressing monocytes and mDCs were induced. The dysregulated TLR-induced IL-1β and IL-6 pathways were more readily detectable in children aged <11 years and from 11 to <21 years, respectively, and did not involve altered HbA(1c) or the presence of one or more autoantibodies. Finally, subjects with autoantibodies had lower amounts of serum chemokine (C-X-C motif) ligand 10 compared with autoantibody-negative subjects. Our data may imply that alterations in innate immune pathways are detectable in genetically susceptible individuals and could be linked with the early course of T1D.

Upregulation of proinflammatory cytokine production in response to bacterial pathogen-associated molecular patterns in dogs with diabetes mellitus undergoing insulin therapy

BACKGROUND

Metabolic alterations associated with diabetes mellitus alter innate immunity. Dogs often develop infectious or inflammatory complications related to diabetes mellitus, yet little is known about the effects of diabetes mellitus on the immune system in this species.

METHODS

Prospective evaluation in dogs with poorly regulated spontaneous type 1 diabetes mellitus (T1DM). In vitro leukocyte cytokine response to lipopolysaccharide (LPS), lipoteichoic acid (LTA), and peptidoglycan (PG) was compared between dogs with T1DM and healthy dogs. Additionally, the effect of acute in vitro glucose exposure on leukocyte tumor necrosis factor (TNF) production from healthy dogs was measured.

RESULTS

Leukocytes from dogs with T1DM had significantly greater TNF production after LTA and PG stimulation compared with leukocytes from healthy dogs. Leukocyte interleukin (IL)-6 production was greater after stimulation with LPS, LTA, PG, and phosphate-buffered saline in the T1DM group. No such difference was noted when evaluating IL-10 production between groups regardless of stimulant. Dogs with T1DM had significantly greater IL-6 to IL-10 production ratios than healthy dogs. Acute exposure to dextrose did not augment cytokine production from healthy canine leukocytes.

CONCLUSIONS

Dogs with T1DM have altered innate immunity characterized by upregulation of proinflammatory cytokine production without a concurrent change in anti-inflammatory cytokine production. This may be one explanation for the common infectious and inflammatory complications associated with T1DM in dogs.

Monocyte-derived DC maturation strategies and related pathways: a transcriptional view

Ex vivo production of highly stimulator mature dendritic cells (DCs) for cellular therapy has been used to treat different pathological conditions with the aim of inducing a specific immune response. In the last decade, several protocols have been developed to mature monocyte-derived DCs: each one has led to the generation of DCs showing different phenotypes and stimulatory abilities, but it is not yet known which one is the best for inducing effective immune responses. We grouped several different maturation protocols according to the downstream pathways they activated and reviewed the shared features at a transcriptomic level to reveal the potential of DCs matured by each protocol to develop Th-polarized immune responses.

Application of serial analysis of gene expression to the study of human genetic disease

Sequence tag analysis using serial analysis of gene expression (SAGE) is a powerful strategy for the quantitative analysis of gene expression in human genetic disorders. SAGE facilitates the measurement of mRNA transcripts and generates a non-biased gene expression profile of normal and pathological disease tissue. In addition, the SAGE technique has the capacity of detecting the expression of novel transcripts allowing for the identification of previously uncharacterised genes, thus providing a unique advantage over the traditional microarray-based approach for expression profiling. The technique has been successful in providing pathological gene expression profiles in a number of common genetic disorders including diabetes, cardiovascular disease, Parkinson disease and Down syndrome. When combined with next generation sequencing platforms, SAGE has the potential to become a more powerful and sensitive technique making it more amenable for diagnostic use. This review will therefore discuss the application of SAGE to several common genetic disorders and will further evaluate its potential use in diagnosing human genetic disease.

Adiponectin-induced secretion of interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1, CCL2) and interleukin-8 (IL-8, CXCL8) is impaired in monocytes from patients with type I diabetes

Background

Systemic adiponectin is reduced in patients with cardiovascular disease (CVD) and low adiponectin may contribute to the pathogenesis of atherosclerosis. However, circulating adiponectin is elevated in type 1 diabetes (T1D) patients, who have also a higher incidence to develop CVD. Because monocytes play an important role in atherosclerosis, we analysed the influence of adiponectin on cytokine and chemokine release in monocytes from T1D patients and controls.

Methods

Systemic adiponectin was determined in the plasma and the high-molecular weight (HMW) form of adiponectin was analysed by immunoblot. Monocytes were isolated from T1D patients and controls and the adiponectin-stimulated release of interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1, CCL2) and interleukin-8 (IL-8, CXCL8) was analysed.

Results

Systemic adiponectin was higher in T1D patients. Immunoblot analysis of the plasma indicate abundance of HMW adiponectin in T1D patients and controls. IL-6, CCL2 and CXCL8 secretion in response to adiponectin were found induced in monocytes from controls whereas only IL-6 was upregulated in T1D cells. The induction of IL-6 by adiponectin was abrogated by an inhibitor of the NFκB pathway.

Conclusion

These data indicate that adiponectin-mediated induction of IL-6, CCL2 and CXCL8 is disturbed in monocytes from T1D patients and therefore elevated systemic adiponectin in T1D patients may be less protective when compared to controls.