A new locus for autosomal dominant generalized epilepsy associated with mild mental retardation on chromosome 3p

MiR-128-3p - a gray eminence of the human central nervous system

MicroRNA-128-3p (miR-128-3p) is a versatile molecule with multiple functions in the physiopathology of the human central nervous system. Perturbations of miR-128-3p, which is enriched in the brain, contribute to a plethora of neurodegenerative disorders, brain injuries, and malignancies, as this miRNA is a crucial regulator of gene expression in the brain, playing an essential role in the maintenance and function of cells stemming from neuronal lineage. However, the differential expression of miR-128-3p in pathologies underscores the importance of the balance between its high and low levels. Significantly, numerous reports pointed to miR-128-3p as one of the most depleted in glioblastoma, implying it is a critical player in the disease's pathogenesis and thus may serve as a therapeutic agent for this most aggressive form of brain tumor. In this review, we summarize the current knowledge of the diverse roles of miR-128-3p. We focus on its involvement in the neurogenesis and pathophysiology of malignant and neurodegenerative diseases. We also highlight the promising potential of miR-128-3p as an antitumor agent for the future therapy of human cancers, including glioblastoma, and as the linchpin of brain development and function, potentially leading to the development of new therapies for neurological conditions.

EPM2AIP1 Immunohistochemistry Can Be Used as Surrogate Testing for MLH1 Promoter Methylation in Endometrial Cancer

Immunohistochemical (IHC) evaluation of DNA mismatch repair proteins (MMR) has become routine practice for Lynch syndrome screening and/or part of diagnostic evaluation in endometrial cancer. Approximately 20% to 30% of endometrial carcinomas demonstrate microsatellite instability due to defective DNA MMR. Vast majority of MLH1/PMS2-deficient tumors are sporadic and show MLH1 promoter methylation. MLH1 methylation testing by quantitative polymerase chain reaction-based technique is time, labor, and tissue intensive with an average institutional turnaround time of 2 weeks. MLH1 and EPM2AIP1 genes share a common promoter whose methylation has been shown to affect both genes. We assessed whether IHC for EPM2AIP1 in combination with MMR proteins can serve as surrogate marker for MLH1 promoter methylation status. We performed a retrospective review of all MLH1/PMS2-deficient endometrial carcinomas that underwent MLH1 promoter methylation testing from January 1 to September 31, 2020, at our institution. Microscopic slides were reviewed and EMP2AIP1 IHC was performed. The results were correlated with MLH1 promoter methylation status (percent methylated rate). A total of 119 cases were identified and successfully tested. Nuclear EPM2AIP1 protein expression was observed in benign endometrial cells and myometrial smooth muscle cells. Loss of nuclear EPM2AIP1 staining was identified in 90/110 (81.8%) methylated tumors with additional 14/110 (12.7%) cases showing aberrant staining patterns. Only 6/110 (5.5%) tumors demonstrated intact EPM2AIP1 nuclear expression in presence of MLH1 promoter methylation. EMP2AIP1 IHC is concordant with MLH1 promoter methylation results in 95% of endometrial carcinomas (94.5% sensitivity, 98.1% positive predictive value) and shows promise as a surrogate marker for methylation testing.

MicroRNA-induced silencing in epilepsy: Opportunities and challenges for clinical application

MicroRNAs are master regulators of gene expression. Single microRNAs influence multiple proteins within diverse molecular pathways and networks. Therefore, changes in levels or activity of microRNAs can have profound effects on cellular function. This makes dysregulated microRNA-induced silencing an attractive potential disease mechanism in complex disorders like epilepsy, where numerous cellular pathways and processes are affected simultaneously. Indeed, several years of research in rodent models have provided strong evidence that acute or recurrent seizures change microRNA expression and function. Moreover, altered microRNA expression has been observed in brain and blood from patients with various epilepsy disorders, such as tuberous sclerosis. MicroRNAs can be easily manipulated using sense or antisense oligonucleotides, opening up opportunities for therapeutic intervention. Here, we summarize studies using these techniques to identify microRNAs that modulate seizure susceptibility, describe protein targets mediating some of these effects, and discuss cellular pathways, for example neuroinflammation, that are controlled by epilepsy-associated microRNAs. We critically assess current gaps in knowledge regarding target- and cell-specificity of microRNAs that have to be addressed before clinical application as therapeutic targets or biomarkers. The recent progress in understanding microRNA function in epilepsy has generated strong momentum to encourage in-depth mechanistic studies to develop microRNA-targeted therapies. Developmental Dynamics 247:94-110, 2018. © 2017 Wiley Periodicals, Inc.

MicroRNA-128 governs neuronal excitability and motor behavior in mice

The control of motor behavior in animals and humans requires constant adaptation of neuronal networks to signals of various types and strengths. We found that microRNA-128 (miR-128), which is expressed in adult neurons, regulates motor behavior by modulating neuronal signaling networks and excitability. miR-128 governs motor activity by suppressing the expression of various ion channels and signaling components of the extracellular signal-regulated kinase ERK2 network that regulate neuronal excitability. In mice, a reduction of miR-128 expression in postnatal neurons causes increased motor activity and fatal epilepsy. Overexpression of miR-128 attenuates neuronal responsiveness, suppresses motor activity, and alleviates motor abnormalities associated with Parkinson's-like disease and seizures in mice. These data suggest a therapeutic potential for miR-128 in the treatment of epilepsy and movement disorders.