Glial fibrillary acidic protein (GFAP) is a novel biomarker for the prediction of autoimmune diabetes

Okinawa-Based Nordic Diet Decreases Plasma Glial Fibrillary Acidic Protein Levels in Type 2 Diabetes Patients

Elevated levels of glial fibrillary acidic protein (GFAP) in plasma reflect neuroinflammation and are linked to cognitive decline. Preclinical studies show that dietary change can attenuate astrocyte reactivity and neuroinflammation. In the current study, we investigate if the Okinawa-based Nordic (O-BN) diet alters plasma GFAP levels in patients with Type 2 Diabetes (T2D), a metabolic disorder associated with cognitive disturbances and an increased risk of dementia. Plasma GFAP levels were measured in T2D patients (n = 30) at baseline, after 3 months of the diet, and after a subsequent 4 months of unrestricted diets. The GFAP levels decreased significantly after 3 months of the diet (p = 0.048) but reverted to baseline levels after 4 months of unrestricted diets. At baseline, the GFAP levels correlated significantly with levels of the neurodegeneration marker neurofilament light polypeptide (r = 0.400*) and, after correcting for age, sex, and body mass index, with proinflammatory plasma cytokines (ranging from r = 0.440* to r = 0.530**) and the metabolic hormone islet amyloid polypeptide (r = 0.478*). We found no correlation with psychological well-being. These results suggest that the O-BN diet reduces neuroinflammation in T2D patients and may thus be an important preventive measure for managing T2D and reducing the risk of neurodegenerative disorders.

APOE ε4 carrier status modifies plasma p-tau181 concentrations in cognitively healthy super-seniors

INTRODUCTION

This study investigates the effect of apolipoprotein E (APOE) genotype on neurology plasma biomarkers in cognitively healthy Super-Seniors.

METHODS

Three hundred seventy plasma specimens from Super-Senior participants ≥ 85 years old, who have never been diagnosed with dementia, cancer, diabetes, cardiovascular, or major pulmonary disease, were analyzed on the Quanterix Simoa HD-X analyzer using commercial Neurology 4-plex E and phosphorylated tau (p-tau)181 assays.

RESULTS

Eighty (22%) participants were APOE ε4 carriers and 290 (73%) were non-carriers. No significant differences were found between APOE ε4 carriers and non-carriers regarding age, sex, or Mini-Mental State Examination scores. In APOE ε4 carriers, plasma amyloid beta 42/40 was lower and p-tau181 and glial fibrillary acidic protein were higher compared to non-APOE ε4 carriers. After adjusting for demographic variables, p-tau181 was the only biomarker to remain significantly associated with APOE ε4 carrier status.

DISCUSSION

APOE ε4 genotype modifies plasma p-tau181 concentration in seniors resilient to age-related clinical disease, suggesting that some Super-Seniors may have Alzheimer's disease pathology without progressing to cognitive decline.

HIGHLIGHTS

Healthy seniors enable identification of associations that may be masked by disease. Plasma phosphorylated tau (p-tau)181 concentrations associate with apolipoprotein E (APOE) ε4 carriership in healthy seniors. APOE should be accounted for when interpreting p-tau181, regardless of disease.

The analgesic effects of insulin and its disorders in streptozotocin-induced short-term diabetes

Evidence suggests that insulin resistance plays an important role in developing diabetes complications. The association between insulin resistance and pain perception is less well understood. This study aimed to investigate the effects of peripheral insulin deficiency on pain pathways in the brain. Diabetes was induced in 60 male rats with streptozotocin (STZ). Insulin was injected into the left ventricle of the brain by intracerebroventricular (ICV) injection, then pain was induced by subcutaneous injection of 2.5% formalin. Samples were collected at 4 weeks after STZ injection. Dopamine (DA), serotonin, reactive oxygen species (ROS), and mitochondrial glutathione (mGSH) were measured by ELISA, and gene factors were assessed by RT-qPCR. In diabetic rats, the levels of DA, serotonin, and mGSH decreased in the nuclei of the thalamus, raphe magnus, and periaqueductal gray, and the levels of ROS increased. In addition, the levels of expression of the neuron-specific enolase and receptor for advanced glycation end genes increased, but the expression of glial fibrillary acidic protein expression was reduced. These results support the findings that insulin has an analgesic effect in non-diabetic rats, as demonstrated by the formalin test. ICV injection of insulin reduces pain sensation, but this was not observed in diabetic rats, which may be due to cell damage ameliorated by insulin.

Vaccine for Diabetes-Where Do We Stand?

Diabetes is an endocrinological disorder with a rapidly increasing number of patients globally. Over the last few years, the alarming status of diabetes has become a pivotal factor pertaining to morbidity and mortality among the youth as well as middle-aged people. Current developments in our understanding related to autoimmune responses leading to diabetes have developed a cause for concern in the prospective usage of immunomodulatory agents to prevent diabetes. The mechanism of action of vaccines varies greatly, such as removing autoreactive T cells and inhibiting the interactions between immune cells. Currently, most developed diabetes vaccines have been tested in animal models, while only a few human trials have been completed with positive outcomes. In this review, we investigate the undergoing clinical trial studies for the development of a prototype diabetes vaccine.

Systematic Review on Post-Mortem Protein Alterations: Analysis of Experimental Models and Evaluation of Potential Biomarkers of Time of Death

Estimating the post-mortem interval (PMI) is a very complex issue due to numerous variables that may affect the calculation. Several authors have investigated the quantitative and qualitative variations of protein expression on post-mortem biological samples in certain time intervals, both in animals and in humans. However, the literature data are very numerous and often inhomogeneous, with different models, tissues and proteins evaluated, such that the practical application of these methods is limited to date. The aim of this paper was to offer an organic view of the state of the art about post-mortem protein alterations for the calculation of PMI through the analysis of the various experimental models proposed. The purpose was to investigate the validity of some proteins as “molecular clocks” candidates, focusing on the evidence obtained in the early, intermediate and late post-mortem interval. This study demonstrates how the study of post-mortem protein alterations may be useful for estimating the PMI, although there are still technical limits, especially in the experimental models performed on humans. We suggest a protocol to homogenize the study of future experimental models, with a view to the next concrete application of these methods also at the crime scene.

Multi-Omics Comparison of the Spontaneous Diabetes Mellitus and Diet-Induced Prediabetic Macaque Models

The prevalence of diabetes mellitus has been increasing for decades worldwide. To develop safe and potent therapeutics, animal models contribute a lot to the studies of the mechanisms underlying its pathogenesis. Dietary induction using is a well-accepted protocol in generating insulin resistance and diabetes models. In the present study, we reported the multi-omics profiling of the liver and sera from both peripheral blood and hepatic portal vein blood from Macaca fascicularis that spontaneously developed Type-2 diabetes mellitus with a chow diet (sDM). The other two groups of the monkeys fed with chow diet and high-fat high-sugar (HFHS) diet, respectively, were included for comparison. Analyses of various omics datasets revealed the alterations of high consistency. Between the sDM and HFHS monkeys, both the similar and unique alterations in the lipid metabolism have been demonstrated from metabolomic, transcriptomic, and proteomic data repeatedly. The comparison of the proteome and transcriptome confirmed the involvement of fatty acid binding protein 4 (FABP4) in the diet-induced pathogenesis of diabetes in macaques. Furthermore, the commonly changed genes between spontaneous diabetes and HFHS diet-induced prediabetes suggested that the alterations in the intra- and extracellular structural proteins and cell migration in the liver might mediate the HFHS diet induction of diabetes mellitus.

The accentuation in post-traumatic stress disorder-like symptoms induced by diabetes in rats is not associated with a further increase in astrocyte activation in the hippocampus

Individuals with post-traumatic stress disorder (PTSD) show increased rates of several serious metabolic diseases. However, little is known about pre-existing metabolic diseases and the development of PTSD. Therefore, we aimed to evaluate the course of post-traumatic stress disorder (PTSD) development in rats with preexisting diabetes. In addition, we quantified glial fibrillary acidic protein (GFAP) in the hippocampus of the experimental animals. For this, we used male Wistar rats and divided them into two groups: saline and alloxan (150 mg/Kg, i.p.). The animals were weighed, and plasma glucose was measured after 48 h of diabetes induction by alloxan. The animals were either exposed to inescapable footshocks or not, followed by social isolation. After 14 days, the animals were re-exposed to the box, and the freezing time was evaluated for 10 min. Over the following days, the animals were tested on the open field, social interaction and forced swimming tests. In another group of animals, elevated plus maze and object recognition tests were performed. Our results demonstrated that animals with diabetes had more pronounced PTSD-like symptoms as a reduction in social interaction, an increase in immobility time in forced swimming, a reduction in permanence in the open arms of the elevated plus maze, and a deficit in the object recognition index more accentuated. However, this did not reflect astrocyte activation in the hippocampus. In conclusion, diabetes accentuates post-traumatic stress disorder-like symptoms but not astrocyte activation in the hippocampus.

GFAP at 50

Fifty years have passed since the discovery of glial fibrillary acidic protein (GFAP) by Lawrence Eng and colleagues. Now recognized as a member of the intermediate filament family of proteins, it has become a subject for study in fields as diverse as structural biology, cell biology, gene expression, basic neuroscience, clinical genetics and gene therapy. This review covers each of these areas, presenting an overview of current understanding and controversies regarding GFAP with the goal of stimulating continued study of this fascinating protein.

Pancreas Optical Clearing and 3-D Microscopy in Health and Diabetes

Although first described over a hundred years ago, tissue optical clearing is undergoing renewed interest due to numerous advances in optical clearing methods, microscopy systems, and three-dimensional (3-D) image analysis programs. These advances are advantageous for intact mouse tissues or pieces of human tissues because samples sized several millimeters can be studied. Optical clearing methods are particularly useful for studies of the neuroanatomy of the central and peripheral nervous systems and tissue vasculature or lymphatic system. Using examples from solvent- and aqueous-based optical clearing methods, the mouse and human pancreatic structures and networks will be reviewed in 3-D for neuro-insular complexes, parasympathetic ganglia, and adipocyte infiltration as well as lymphatics in diabetes. Optical clearing with multiplex immunofluorescence microscopy provides new opportunities to examine the role of the nervous and circulatory systems in pancreatic and islet functions by defining their neurovascular anatomy in health and diabetes.

Immune System Sex Differences May Bridge the Gap Between Sex and Gender in Fibromyalgia

The fibromyalgia syndrome (FMS) is characterized by chronic widespread pain, sleep disturbances, fatigue, and cognitive alterations. A limited efficacy of targeted treatment and a high FMS prevalence (2–5% of the adult population) sums up to high morbidity. Although, altered nociception has been explained with the central sensitization hypothesis, which may occur after neuropathy, its molecular mechanism is not understood. The marked female predominance among FMS patients is often attributed to a psychosocial predisposition of the female gender, but here we will focus on sex differences in neurobiological processes, specifically those of the immune system, as various immunological biomarkers are altered in FMS. The activation of innate immune sensors is compatible with a neuropathy or virus-induced autoimmune diseases. Considering sex differences in the immune system and the clustering of FMS with autoimmune diseases, we hypothesize that the female predominance in FMS is due to a neuropathy-induced autoimmune pathophysiology. We invite the scientific community to verify the autoimmune hypothesis for FMS.

Dietary SCFAs, IL-22, and GFAP: The Three Musketeers in the Gut-Neuro-Immune Network in Type 1 Diabetes

Microbial metabolites have a profound effect on the development of type 1 diabetes (T1D). The cross-talk between the gut microbiota, the nervous system, and immune system is necessary to establish and maintain immune and gut tolerance. As quoted by Hippocrates, "All disease begins in the gut." Although this has been recognized for 2,000 years, the connection between the gut and autoimmune T1D is not yet well-understood. Here, we outline new advances supported by our research and others that have contributed to elucidate the impact of microbial metabolites on the physiology of the pancreas and the gut through their remarkable effect on the immune and nervous system. Among many of the mechanisms involved in the gut-beta-cell-immune cross-talk, glial fibrillary acidic protein (GFAP)-expressing cells are critical players in the development of invasive insulitis. Besides, this review reveals a novel mechanism for microbial metabolites by stimulating IL-22, an essential cytokine for gut homeostasis and beta-cell survival. The close connections between the gut and the pancreas are highlighted through our review as microbial metabolites recirculate through the whole body and intimately react with the nervous system, which controls essential disorders associated with diabetes. As such, we discuss the mechanisms of action of microbial metabolites or short-chain fatty acids (SCFAs), IL-22, and GFAP on beta-cells, gut epithelial cells, neurons, and glial cells via metabolite sensing receptors or through epigenetic effects. The fine-tuned gut-neuro-immune network may be profoundly affected by SCFA deficiency related to dysbiosis and diet alterations at very early stages of the initiation of the disease. Thus, dampening the initial immune response or preventing the perpetuation of the immune response by maintaining the integrity of the gut is among the alternative approaches to prevent T1D.

Pancreatic ductal cell antigens are important in the development of invasive insulitis in Non-Obese Diabetic mice

Type 1 Diabetes (T1D) is an autoimmune disease in which insulin producing beta cells of the pancreas are selectively destroyed. Glial Fibrillary Acidic Protein (GFAP) expressed in peri-islet Schwann cells (pSCs) and in the ductal cells of the pancreas is one of the candidate autoantigens for T1D. Immune responses to GFAP expressing cell types precede the islet autoimmunity in Non-Obese Diabetic (NOD) mice. By removing MHC class I from GFAP expressing cell types, we tested the role of autoantigens presented by these cell types in the development of invasive insulitis. Our findings indicate that antigens expressed by pancreatic ductal cells are important in the development of invasive insulitis in NOD mice.

The Role of Accessory Cells in Islet Homeostasis

PURPOSES OF REVIEW

Scattered throughout the pancreas, the endocrine islets rely on neurovascular support for signal relay to regulate hormone secretion and for maintaining tissue homeostasis. The islet accessory cells (or components) of neurovascular tissues include the endothelial cells, pericytes, smooth muscle cells, neurons (nerve fibers), and glia. Research results derived from experimental diabetes and islet transplantation indicate that the accessory cells are reactive in islet injury and can affect islet function and homeostasis in situ or in an ectopic environment.

RECENT FINDINGS

Recent advances in cell labeling and tissue imaging have enabled investigation of islet accessory cells to gain insights into their network structures, functions, and remodeling in disease. It has become clear that in diabetes, the islet neurovascular tissues are not just bystanders damaged in neuropathy and vascular complications; rather, they participate in islet remodeling in response to changes in the microenvironment. Because of the fundamental differences between humans and animal models in neuroinsular cytoarchitecture and cell proliferation, examination of islet accessory cells in clinical specimens and donor pancreases warrants further attention.

Gene therapy with the angiogenic neuropeptide secretoneurin ameliorates experimental diabetic neuropathy

The pathogenesis of diabetic neuropathy remains enigmatic. Damage to the vasa nervorum may be responsible for this disorder. Recently, we showed that secretoneurin (SN) induces angiogenesis in hindlimb and myocardial ischemia. Moreover, beneficial effects were observed in wound healing. We therefore hypothesized that SN therapy may ameliorate diabetic neuropathy. We used db/db mice as animal model for neuropathy. Gene therapy was accomplished by intramuscular injection of SN plasmid along the sciatic nerve. Sciatic nerve motor and sensory conduction velocities were then measured for 9 wk. Nerve conduction velocities showed normal values in heterozygous mice for the observational period, but were severely reduced in homozygous mice in which velocities were significantly improved by SN, but not by control plasmid gene therapy. The reaction time in the tail-flick test improved significantly in SN-treated animals. The induction of growth of vasa nervorum seems to be part of the underlying mechanism. In addition, SN positively affected Schwann cell function in vitro and induced activation of important signaling pathways. Our observations suggest that SN exerts beneficial effects on nerve function in vivo and on Schwann cells in vitro. It therefore may be a promising treatment option for diabetic neuropathy.-Theurl, M., Lener, D., Albrecht-Schgoer, K., Beer, A., Schgoer, W., Liu, Y., Stanzl, U., Fischer-Colbrie, R., Kirchmair, R. Gene therapy with the angiogenic neuropeptide secretoneurin ameliorates experimental diabetic neuropathy.

Human cancer stem cells are a target for cancer prevention using (-)-epigallocatechin gallate

Purpose

Our previous experiments show that the main constituent of green-tea catechins, (−)-epigallocatechin gallate (EGCG), completely prevents tumor promotion on mouse skin initiated with 7,12-dimethylbenz(a)anthracene followed by okadaic acid and that EGCG and green tea extract prevent cancer development in a wide range of target organs in rodents. Therefore, we focused our attention on human cancer stem cells (CSCs) as targets of cancer prevention and treatment with EGCG.

Methods

The numerous reports concerning anticancer activity of EGCG against human CSCs enriched from cancer cell lines were gathered from a search of PubMed, and we hope our review of the literatures will provide a broad selection for the effects of EGCG on various human CSCs.

Results

Based on our theoretical study, we discuss the findings as follows: (1) Compared with the parental cells, human CSCs express increased levels of the stemness markers Nanog, Oct4, Sox2, CD44, CD133, as well as the EMT markers, Twist, Snail, vimentin, and also aldehyde dehydrogenase. They showed decreased levels of E-cadherin and cyclin D1. (2) EGCG inhibits the transcription and translation of genes encoding stemness markers, indicating that EGCG generally inhibits the self-renewal of CSCs. (3) EGCG inhibits the expression of the epithelial-mesenchymal transition phenotypes of human CSCs. (4) The inhibition of EGCG of the stemness of CSCs was weaker compared with parental cells. (5) The weak inhibitory activity of EGCG increased synergistically in combination with anticancer drugs.

Conclusions

Green tea prevents human cancer, and the combination of EGCG and anticancer drugs confers cancer treatment with tissue-agnostic efficacy.