Background: Pigment epithelium-derived factor (PEDF) interacts with its receptor PEDF-R to exert cytoprotection. Results: Alanine scanning of a small fragment (17-mer) of PEDF reveals key interacting residues for binding PEDF-R and alternative retinoprotective peptide versions with higher efficacy. Conclusion: The 17-mer contains a novel PEDF-R binding region important for retinoprotection. Significance: Altered PEDF peptides could be exploited pharmacologically to improve protection of photoreceptors from degeneration.
The dentate gyrus (DG) controls information flow into the hippocampus and is critical for learning, memory, pattern separation, and spatial coding, while DG dysfunction is associated with neuropsychiatric disorders. Despite its importance, the molecular mechanisms regulating DG neural circuit assembly and function remain unclear. Here, we identify the Rac-GEF Tiam1 as an important regulator of DG development and associated memory processes. In the hippocampus, Tiam1 is predominantly expressed in the DG throughout life. Global deletion of Tiam1 in male mice results in DG granule cells with simplified dendritic arbors, reduced dendritic spine density, and diminished excitatory synaptic transmission. Notably, DG granule cell dendrites and synapses develop normally in Tiam1 KO mice, resembling WT mice at postnatal day 21 (P21), but fail to stabilize, leading to dendrite and synapse loss by P42. These results indicate that Tiam1 promotes DG granule cell dendrite and synapse stabilization late in development. Tiam1 loss also increases the survival, but not the production, of adultborn DG granule cells, possibly because of greater circuit integration as a result of decreased competition with mature granule cells for synaptic inputs. Strikingly, both male and female mice lacking Tiam1 exhibit enhanced contextual fear memory and context discrimination. Together, these results suggest that Tiam1 is a key regulator of DG granule cell stabilization and function within hippocampal circuits. Moreover, based on the enhanced memory phenotype of Tiam1 KO mice, Tiam1 may be a potential target for the treatment of disorders involving memory impairments.
Adults with intellectual and developmental disabilities (AIDD) experience significant oral health disparities, partially due to perceived behavioral issues. This article describes the preliminary outcomes of a developing interdisciplinary (dental, medical, behavioral) program involving a behavioral intervention for AIDD previously receiving preventative dental care with sedation, general anesthesia, or protective stabilization (SAS). After a baseline assessment, a board-certified behavior analyst implemented increasingly complex behavioral interventions during simulated dental visits. Prior to COVID-19 pandemic-related restrictions, there were 32 active participants; 15 (46.9%) successfully completed a focused, real dental exam with simple behavioral interventions and 17 (53.1%) remain in treatment. These preliminary results suggest that many AIDD previously receiving SAS may participate in a preventative dental exam with minimal behavioral supports, if given the opportunity.
Cyclin‐dependent kinase‐like 5 (CDKL5) deficiency disorder (CDD) is caused by heterozygous or hemizygous variants in CDKL5 and is characterized by refractory epilepsy, cognitive and motor impairments, and cerebral visual impairment. CDKL5 has multiple transcripts, of which the longest transcripts, NM_003159 and NM_001037343, have been used historically in clinical laboratory testing. However, the transcript NM_001323289 is the most highly expressed in brain and contains 170 nucleotides at the 3′ end of its last exon that are noncoding in other transcripts. Two truncating variants in this region have been reported in association with a CDD phenotype. To clarify the significance and range of phenotypes associated with late truncating variants in this region of the predominant transcript in the brain, we report detailed information on two individuals, updated clinical information on a third individual, and a summary of published and unpublished individuals reported in ClinVar. The two new individuals (one male and one female) each had a relatively mild clinical presentation including periods of pharmaco‐responsive epilepsy, independent walking and limited purposeful communication skills. A previously reported male continued to have a severe phenotype. Overall, variants in this region demonstrate a range of clinical severity consistent with reports in CDD but with the potential for milder presentation.
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