Ageing impairs the regenerative capacity of regulatory T cells in mouse central nervous system remyelination.

Myelin regeneration (remyelination) is essential to prevent neurodegeneration in demyelinating diseases such as Multiple Sclerosis, however, its efficiency declines with age. Regulatory T cells (Treg) recently emerged as critical players in tissue regeneration, including remyelination. However, the effect of ageing on Treg-mediated regenerative processes is poorly understood. Here, we show that expansion of aged Treg does not rescue age-associated remyelination impairment due to an intrinsically diminished capacity of aged Treg to promote oligodendrocyte differentiation and myelination in male and female mice. This decline in regenerative Treg functions can be rescued by a young environment. We identified Melanoma Cell Adhesion Molecule 1 (MCAM1) and Integrin alpha 2 (ITGA2) as candidates of Treg-mediated oligodendrocyte differentiation that decrease with age. Our findings demonstrate that ageing limits the neuroregenerative capacity of Treg, likely limiting their remyelinating therapeutic potential in aged patients, and describe two mechanisms implicated in Treg-driven remyelination that may be targetable to overcome this limitation.

ANO1, CaV1.2, and IP3R form a localized unit of EC-coupling in mouse pulmonary arterial smooth muscle.

Pulmonary arterial (PA) smooth muscle cells (PASMC) generate vascular tone in response to agonists coupled to Gq-protein receptor signaling. Such agonists stimulate oscillating calcium waves, the frequency of which drives the strength of contraction. These Ca2+ events are modulated by a variety of ion channels including voltage-gated calcium channels (CaV1.2), the Tmem16a or Anoctamin-1 (ANO1)-encoded calcium-activated chloride (CaCC) channel, and Ca2+ release from the sarcoplasmic reticulum through inositol-trisphosphate receptors (IP3R). Although these calcium events have been characterized, it is unclear how these calcium oscillations underly a sustained contraction in these muscle cells. We used smooth muscle-specific ablation of ANO1 and pharmacological tools to establish the role of ANO1, CaV1.2, and IP3R in the contractile and intracellular Ca2+ signaling properties of mouse PA smooth muscle expressing the Ca2+ biosensor GCaMP3 or GCaMP6. Pharmacological block or genetic ablation of ANO1 or inhibition of CaV1.2 or IP3R, or Ca2+ store depletion equally inhibited 5-HT-induced tone and intracellular Ca2+ waves. Coimmunoprecipitation experiments showed that an anti-ANO1 antibody was able to pull down both CaV1.2 and IP3R. Confocal and superresolution nanomicroscopy showed that ANO1 coassembles with both CaV1.2 and IP3R at or near the plasma membrane of PASMC from wild-type mice. We conclude that the stable 5-HT-induced PA contraction results from the integration of stochastic and localized Ca2+ events supported by a microenvironment comprising ANO1, CaV1.2, and IP3R. In this model, ANO1 and CaV1.2 would indirectly support cyclical Ca2+ release events from IP3R and propagation of intracellular Ca2+ waves.

Loss of TRPV2-mediated blood flow autoregulation recapitulates diabetic retinopathy in rats.

Loss of retinal blood flow autoregulation is an early feature of diabetes that precedes the development of clinically recognizable diabetic retinopathy (DR). Retinal blood flow autoregulation is mediated by the myogenic response of the retinal arterial vessels, a process that is initiated by the stretch­dependent activation of TRPV2 channels on the retinal vascular smooth muscle cells (VSMCs). Here, we show that the impaired myogenic reaction of retinal arterioles from diabetic animals is associated with a complete loss of stretch­dependent TRPV2 current activity on the retinal VSMCs. This effect could be attributed, in part, to TRPV2 channel downregulation, a phenomenon that was also evident in human retinal VSMCs from diabetic donors. We also demonstrate that TRPV2 heterozygous rats, a nondiabetic model of impaired myogenic reactivity and blood flow autoregulation in the retina, develop a range of microvascular, glial, and neuronal lesions resembling those observed in DR, including neovascular complexes. No overt kidney pathology was observed in these animals. Our data suggest that TRPV2 dysfunction underlies the loss of retinal blood flow autoregulation in diabetes and provide strong support for the hypothesis that autoregulatory deficits are involved in the pathogenesis of DR.

High throughput screening for expanded CTG repeats in myotonic dystrophy type 1 using melt curve analysis.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is caused by CTG repeat expansions in the DMPK gene and is the most common form of muscular dystrophy. Patients can have long delays from onset to diagnosis, since clinical signs and symptoms are often nonspecific and overlapping with other disorders. Clinical genetic testing by Southern blot or triplet-primed PCR (TP-PCR) is technically challenging and cost prohibitive for population surveys. METHODS: Here, we present a high throughput, low-cost screening tool for CTG repeat expansions using TP-PCR followed by high resolution melt curve analysis with saturating concentrations of SYBR GreenER dye. RESULTS: We determined that multimodal melt profiles from the TP-PCR assay are a proxy for amplicon length stoichiometry. In a screen of 10,097 newborn blood spots, melt profile analysis accurately reflected the tri-modal distribution of common alleles from 5 to 35 CTG repeats, and identified the premutation and full expansion alleles. CONCLUSION: We demonstrate that robust detection of expanded CTG repeats in a single tube can be achieved from samples derived from specimens with minimal template DNA such as dried blood spots (DBS). This technique is readily adaptable to large-scale testing programs such as population studies and newborn screening programs.

Population-Based Prevalence of Myotonic Dystrophy Type 1 Using Genetic Analysis of Statewide Blood Screening Program.

OBJECTIVE: To determine whether the genetic prevalence of the CTG expansion in the DMPK gene associated with myotonic dystrophy type 1 (DM1) in an unbiased cohort is higher than previously reported population estimates, ranging from 5 to 20 per 100,000 individuals. METHODS: This study used a cross-sectional cohort of deidentified dried blood spots from the newborn screening program in the state of New York, taken from consecutive births from 2013 to 2014. Blood spots were screened for the CTG repeat expansion in the DMPK gene using triplet-repeat primed PCR and melt curve analysis. Melt curve morphology was assessed by 4 blinded reviewers to identify samples with possible CTG expansion. Expansion of the CTG repeat was validated by PCR fragment sizing using capillary electrophoresis for samples classified as positive or premutation to confirm the result. Prevalence was calculated as the number of samples with CTG repeat size ≥50 repeats compared to the overall cohort. RESULTS: Of 50,382 consecutive births, there were 24 with a CTG repeat expansion ≥50, consistent with a diagnosis of DM1. This represents a significantly higher DM1 prevalence of 4.76 per 10,000 births (95% confidence interval 2.86-6.67) or 1 in every 2,100 births. There were an additional 96 samples (19.1 per 10,000 or 1 in 525 births) with a CTG expansion in the DMPK gene in the premutation range (CTG)35-49. CONCLUSION: The prevalence of individuals with CTG repeat expansions in DMPK is up to 5 times higher than previous reported estimates. This suggests that DM1, with multisystemic manifestations, is likely underdiagnosed in practice.

Aging and Neurodegenerative Disease: Is the Adaptive Immune System a Friend or Foe?

Neurodegenerative diseases of the central nervous system (CNS) are characterized by progressive neuronal death and neurological dysfunction, leading to increased disability and a loss of cognitive or motor functions. Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis have neurodegeneration as a primary feature. However, in other CNS diseases such as multiple sclerosis, stroke, traumatic brain injury, and spinal cord injury, neurodegeneration follows another insult, such as demyelination or ischaemia. Although there are different primary causes to these diseases, they all share a hallmark of neuroinflammation. Neuroinflammation can occur through the activation of resident immune cells such as microglia, cells of the innate and adaptive peripheral immune system, meningeal inflammation and autoantibodies directed toward components of the CNS. Despite chronic inflammation being pathogenic in these diseases, local inflammation after insult can also promote endogenous regenerative processes in the CNS, which are key to slowing disease progression. The normal aging process in the healthy brain is associated with a decline in physiological function, a steady increase in levels of neuroinflammation, brain shrinkage, and memory deficits. Likewise, aging is also a key contributor to the progression and exacerbation of neurodegenerative diseases. As there are associated co-morbidities within an aging population, pinpointing the precise relationship between aging and neurodegenerative disease progression can be a challenge. The CNS has historically been considered an isolated, "immune privileged" site, however, there is mounting evidence that adaptive immune cells are present in the CNS of both healthy individuals and diseased patients. Adaptive immune cells have also been implicated in both the degeneration and regeneration of the CNS. In this review, we will discuss the key role of the adaptive immune system in CNS degeneration and regeneration, with a focus on how aging influences this crosstalk.

Ancestry of the Timorese: age-related macular degeneration associated genotype and allele sharing among human populations from throughout the world.

We observed that the third leading cause of blindness in the world, age-related macular degeneration (AMD), occurs at a very low documented frequency in a population-based cohort from Timor-Leste. Thus, we determined a complete catalog of the ancestry of the Timorese by analysis of whole exome chip data and haplogroup analysis of SNP genotypes determined by sequencing the Hypervariable I and II regions of the mitochondrial genome and 17 genotyped YSTR markers obtained from 535 individuals. We genotyped 20 previously reported AMD-associated SNPs in the Timorese to examine their allele frequencies compared to and between previously documented AMD cohorts of varying ethnicities. For those without AMD (average age > 55 years), genotype and allele frequencies were similar for most SNPs with a few exceptions. The major risk allele of HTRA1 rs11200638 (10q26) was at a significantly higher frequency in the Timorese, as well as 3 of the 5 protective CFH (1q32) SNPs (rs800292, rs2284664, and rs12066959). Additionally, the most commonly associated AMD-risk SNP, CFH rs1061170 (Y402H), was also seen at a much lower frequency in the Korean and Timorese populations than in the assessed Caucasian populations (C ~7 vs. ~40%, respectively). The difference in allele frequencies between the Timorese population and the other genotyped populations, along with the haplogroup analysis, also highlight the genetic diversity of the Timorese. Specifically, the most common ancestry groupings were Oceanic (Melanesian and Papuan) and Eastern Asian (specifically Han Chinese). The low prevalence of AMD in the Timorese population (2 of 535 randomly selected participants) may be due to the enrichment of protective alleles in this population at the 1q32 locus.

Clinical Characteristics of Uveal Melanoma in Patients With Germline BAP1 Mutations.

IMPORTANCE: Somatic mutations in BAP1 (BRCA1-associated protein 1 gene) are frequently identified in uveal melanoma. To date, the role of germline BAP1 mutations in uveal melanoma has not been characterized. OBJECTIVE: To characterize the clinical phenotype of uveal melanoma in patients with germline BAP1 mutations. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study at an academic ophthalmology referral center among 507 patients with uveal melanoma who consented for collection of blood samples. The study dates were June 22, 1992, to December 14, 2010. MAIN OUTCOMES AND MEASURES: Clinical characteristics of uveal melanoma and the development of metastases. BAP1 gene sequencing from blood samples of patients with uveal melanoma was correlated with clinical characteristics. RESULTS: Of 507 blood samples analyzed, 25 patients (4.9%) exhibited 18 BAP1 polymorphisms, of which 9 were novel. Computational analyses predicted that 8 BAP1 mutations in 8 patients (1.6%) were likely to result in damaged BAP1 protein. Five of these 8 mutations were novel. These 8 patients were compared with 482 patients in whom no BAP1 polymorphisms were identified. In univariate analyses, patients with germline BAP1 mutations exhibited larger tumor diameters (mean, 15.9 vs 12.3 mm; P = .004) and higher rates of ciliary body involvement (75.0% vs 21.6%, P = .002) and metastases (71.4% vs 18.0%, P = .003) compared with control subjects. Patients with germline BAP1 mutations exhibited increased frequency of family history of cancer (100% vs 65.9%, P = .06), particularly cutaneous melanoma (62.5% vs 9.9%, P < .001) and ocular melanoma (25.0% vs 1.9%, P = .01). No differences were identified in age at diagnosis, sex, history of other malignant neoplasm, presenting visual acuity, distance of the tumor from the optic nerve or fovea, iris involvement, extrascleral extension, or tumor pigmentation. Germline BAP1 mutations increased risk of metastasis independent of ciliary body involvement (P = .02). Germline BAP1 mutation approached significance as an independent risk factor for metastasis (P = .09). CONCLUSIONS AND RELEVANCE: These data suggest that germline BAP1 mutations occur infrequently in uveal melanoma and are associated with larger tumors and higher rates of ciliary body involvement, 2 known risk factors for metastasis.