In type 1 diabetes (T1D), β-cell loss is silent during disease progression. Methylation-sensitive quantitative real-time PCR (qPCR) of β-cell-derived DNA in the blood can serve as a biomarker of β-cell death in T1D. Amylin is highly expressed by β-cells in the islet. Here we examined whether demethylated circulating free amylin DNA (cfDNA) may serve as a biomarker of β-cell death in T1D. β cells showed unique methylation patterns within the amylin coding region that were not observed with other tissues. The design and use of methylation-specific primers yielded a strong signal for demethylated amylin in purified DNA from murine islets when compared with other tissues. Similarly, methylation-specific primers detected high levels of demethylated amylin DNA in human islets and enriched human β-cells. In vivo testing of the primers revealed an increase in demethylated amylin cfDNA in sera of non-obese diabetic (NOD) mice during T1D progression and following the development of hyperglycemia. This increase in amylin cfDNA did not mirror the increase in insulin cfDNA, suggesting that amylin cfDNA may detect β-cell loss in serum samples where insulin cfDNA is undetected. Finally, purified cfDNA from recent onset T1D patients yielded a high signal for demethylated amylin cfDNA when compared with matched healthy controls. These findings support the use of demethylated amylin cfDNA for detection of β-cell-derived DNA. When utilized in conjunction with insulin, this latest assay provides a comprehensive multi-gene approach for the detection of β-cell loss.

The myelin sheath that coats axons allows rapid propagation of electrical impulses across the nervous system. Oligodendrocytes (ODs) are myelin-producing cells of the central nervous system (CNS) responsible for wrapping the axons of neurons. Multiple sclerosis (MS) is a demyelinating disease of the CNS identifiable by white and gray matter lesions. These lesions consist of axons that have lost their myelin through an autoimmune response to myelin and ODs. Current treatments for MS target the autoimmune aspect of the disease. However, these immunomodulators do not directly enhance the process of remyelination. The ability to remyelinate lesions can be enhanced by neural progenitor cells that can differentiate into ODs and replace lost myelin, although successful remyelination is complex and dependent on multiple factors. The restoration of lost myelin might protect the axon from degeneration and restore optimal conduction of impulses in MS patients, requiring further research on proremyelinating therapies. The combination of immunomodulators and remyelinating enhancers might be the best course of treatment for many MS patients. This Review discusses demyelination in MS, the mechanisms of remyelination, and current therapies designed to promote remyelination in MS patients.

Background: Islet endothelial cells induce pseudoislet formation in ␤ cells and ECM deposition. Results: Pseudoislet formation results in glycosylation and increased cell surface expression of integrin ␤1. Conclusion: Posttranslational modifications of integrins in ␤ cells are a novel mechanism for controlling ␤-cell function. Significance: Alternative integrin ␤1 glycosylation represents a novel mechanism that may control ␤ cells in health and in disease.

Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system (CNS). Minimally invasive biomarkers of MS are required for disease diagnosis and treatment. Differentially methylated circulating-free DNA (cfDNA) is a useful biomarker for disease diagnosis and prognosis, and may offer to be a viable approach for understanding MS. Here, methylation-specific primers and quantitative real-time PCR were used to study methylation patterns of the myelin oligodendrocyte glycoprotein (MOG) gene, which is expressed primarily in myelin-producing oligodendrocytes (ODCs). MOG-DNA was demethylated in O4+ ODCs in mice and in DNA from human oligodendrocyte precursor cells (OPCs) when compared with other cell types. In the cuprizone-fed mouse model of demyelination, ODC derived demethylated MOG cfDNA was increased in serum and was associated with tissue-wide demyelination, demonstrating the utility of demethylated MOG cfDNA as a biomarker of ODC death. Collected sera from patients with active (symptomatic) relapsing-remitting MS (RRMS) demonstrated a higher signature of demethylated MOG cfDNA when compared with patients with inactive disease and healthy controls. Taken together, these results offer a minimally invasive approach to measuring ODC death in the blood of MS patients that may be used to monitor disease progression.

BackgroundGestational diabetes mellitus (GDM) affects approximately 7–17 % of all pregnancies and has been recognized as a significant risk factor to neonatal and maternal health. Postpartum, GDM significantly increases the likelihood of developing type 2 diabetes (T2D). While it is well established that insulin resistance and impaired β-cell function contribute to GDM development, the role of active β-cell loss remains unknown. Differentially methylated circulating free DNA (cfDNA) is a minimally invasive biomarker of β-cell loss in type 1 diabetes mellitus. Here we use cfDNA to examine the levels of β-cell death in women with GDM.MethodsSecond to third-trimester pregnant women with GDM were compared with women with normal pregnancy (PRG), women at postpartum (PP), and non-pregnant (NP) women. Fasting glucose levels, insulin, and C-peptide levels were measured. Serum samples were collected and cfDNA purified and bisulfite treated. Methylation-sensitive probes capable of differentiating between β-cell-derived DNA (demethylated) and non-β-cell-derived DNA (methylated) were used to measure the presence of β-cell loss in the blood.ResultsGDM was associated with elevated fasting glucose levels (GDM = 185.9 ± 5.0 mg/dL) and reduced fasting insulin and c-peptide levels when compared with NP group. Interestingly, β-cell derived insulin DNA levels were significantly lower in women with GDM when compared with PRG, NP, and PP groups (demethylation index: PRG = 7.74 × 10−3 ± 3.09 × 10−3, GDM = 1.01 × 10−3 ± 5.86 × 10−4, p < 0.04; NP = 4.53 × 10−3 ± 1.62 × 10−3, PP = 3.24 × 10−3 ± 1.78 × 10−3).ConclusionsThese results demonstrate that β-cell death is reduced in women with GDM. This reduction is associated with impaired insulin production and hyperglycemia, suggesting that β-cell death does not contribute to GDM during the 2nd and 3rd trimester of pregnancy.