CSNK2B, which encodes the beta subunit of casein kinase II (CK2), plays an important role in neuron morphology and synaptic transmission. Variants in CSNK2B associated with epilepsy and/or intellectual disability (ID)/developmental delay (DD) have been reported in five cases only. Among the 816 probands suspected hereditary epilepsy whose initial report of trio-based whole exome sequencing (WES) were negative, 10 de novo pathogenic or likely pathogenic variants of CSNK2B in nine probands were identified after reanalysis of their raw Trio-WES data. Six of the nine epileptic patients had ID/DD. The age of seizure onset of these nine patients with CSNK2B variants ranged from 2–12 months. Eight patients had age of seizure onset of less than 6 months. The epilepsy of most probands (8/9) was generalized tonic-clonic seizure and clustered (6/9). Most patients had normal electroencephalogram (5/9) and brain magnetic resonance image (7/9) results. Most patients (7/9) had easy-to-control seizures. Levetiracetam was the most commonly used drug in seizure-free patients (5/7). The variants detected in five patients (5/9, 55.6%) were located in the zinc-binding domain. In summary, our research provided evidence that variants in CSNK2B are associated with epilepsy with or without ID/DD. CSNK2B-related epilepsy is relatively easy to be controlled. The zinc-binding domain appears to be the hotspot region for mutation.

Diabetes impairs physiological angiogenesis by molecular mechanisms that are not fully understood. Methylglyoxal (MGO), a metabolite of glycolysis, is increased in patients with diabetes. This study defined the role of MGO in angiogenesis impairment and tested the mechanism in diabetic animals. Endothelial cells and mouse aortas were subjected to Western blot analysis of vascular endothelial growth factor receptor 2 (VEGFR2) protein levels and angiogenesis evaluation by endothelial cell tube formation/migration and aortic ring assays. Incubation with MGO reduced VEGFR2 protein, but not mRNA, levels in a time and dose dependent manner. Genetic knockdown of the receptor for advanced glycation endproducts (RAGE) attenuated the reduction of VEGFR2. Overexpression of Glyoxalase 1, the enzyme that detoxifies MGO, reduced the MGO-protein adducts and prevented VEGFR2 reduction. The VEGFR2 reduction was associated with impaired angiogenesis. Suppression of autophagy either by inhibitors or siRNA, but not of the proteasome and caspase, normalized both the VEGFR2 protein levels and angiogenesis. Conversely, induction of autophagy either by rapamycin or overexpression of LC3 and Beclin-1 reduced VEGFR2 and angiogenesis. MGO increased endothelial LC3B and Beclin-1, markers of autophagy, which were accompanied by an increase of both autophagic flux (LC3 punctae) and co-immunoprecipitation of VEGFR2 with LC3. Pharmacological or genetic suppression of peroxynitrite (ONOO−) generation not only blocked the autophagy but also reversed the reduction of VEGFR2 and angiogenesis. Like MGO-treated aortas from normglycemic C57BL/6J mice, aortas from diabetic db/db and Akita mice presented reductions of angiogenesis or VEGFR2. Administration of either autophagy inhibitor ex vivo or superoxide scavenger in vivo abolished the reductions. Taken together, MGO reduces endothelial angiogenesis through RAGE-mediated, ONOO–dependent and autophagy-induced VEGFR2 degradation, which may represent a new mechanism for diabetic angiogenesis impairment.

Objective Although the connection of oxidative stress and inflammation has been long recognized in diabetes, the underlying mechanisms are not fully elucidated. This study defined the role of 26S proteasomes in promoting vascular inflammatory response in early diabetes. Methods and Results The 26S proteasome functionality, markers of autophagy, and unfolded protein response (UPR) were assessed in: (a) cultured 26S proteasome reporter cells and endothelial cells challenged with high glucose, (b) transgenic reporter (UbG76V-GFP) and wild type (C57BL/6J) mice rendered diabetic, and (c) genetically diabetic (Akita and OVE26) mice. In glucose-challenged cells, and also in aortic, renal, and retinal tissues from diabetic mice, enhanced 26S proteasome functionality was observed, evidenced by augmentation of proteasome (chymotrypsin-like) activities and reduction in 26S proteasome reporter proteins, accompanied by increased nitrotyrosine-containing proteins. Also, while IκBα proteins were decreased, an increase was found in NF-κB nucleus translocation, which enhanced the NF-κB-mediated pro-inflammatory response, without affecting markers of autophagy or UPR. Importantly, the alterations were abolished by MG132 administration, siRNA knockdown of PA700 (proteasome activator protein complex), or superoxide scavenging in vivo. Conclusions Early hyperglycemia enhances 26S proteasome functionality, not autophagy or UPR, through peroxynitrite/superoxide-mediated PA700-dependent proteasomal activation, which elevates NF-κB-mediated endothelial inflammatory response in early diabetes.

PurposeTo determine the role of mosaicism in the pathogenesis and inheritance of Rett and Rett-like disorders.MethodsWe recruited 471 Rett and Rett-like patients. Panel-sequencing targeting MECP2, CDKL5, and FOXG1 was performed. Mosaicism was quantified in 147 patients by a Bayesian genotyper. Candidates were validated by amplicon sequencing and digital PCR. Germline mosaicism of 21 fathers with daughters carrying pathogenic MECP2 variants was further quantified.ResultsPathogenic variants of MECP2/CDKL5/FOXG1 were found in 324/471 (68.7%) patients. Somatic MECP2 mosaicism was confirmed in 5/471 (1.1%) patients, including 3/18 males (16.7%) and 2/453 females (0.4%). Three of the five patients with somatic MECP2 mosaicism had mosaicism at MECP2-Arg106. Germline MECP2 mosaicism was detected in 5/21 (23.8%) fathers.ConclusionThis is the first systematic screening of somatic and paternal germline MECP2 mosaicism at a cohort level. Our findings indicate that somatic MECP2 mosaicism contributes directly to the pathogenicity of Rett syndrome, especially in male patients. MECP2-Arg106 might be a mosaic hotspot. The high proportion of paternal germline MECP2 mosaicism indicates an underestimated mechanism underlying the paternal origin bias of MECP2 variants. Finally, this study provides an empirical foundation for future studies of genetic disorders caused by de novo variations of strong paternal origin.