Gain of function of a metalloproteinase associated with multiple myeloma, bicuspid aortic valve, and Von Hippel-Lindau syndrome.

A patient diagnosed with multiple myeloma, bicuspid aortic valve, and Von Hippel-Lindau syndrome underwent whole-exome sequencing seeking a unified genetic cause for these three pathologies. The patient possessed a single-point mutation of arginine to cysteine (R24C) in the N-terminal region(pro-domain) of matrix metalloproteinase 9 (MMP-9). The pro-domain interacts with the catalytic site of this enzyme rendering it inactive.

Efficient Generation of CA3 Neurons from Human Pluripotent Stem Cells Enables Modeling of Hippocampal Connectivity In Vitro.

Despite widespread interest in using human induced pluripotent stem cells (hiPSCs) in neurological disease modeling, a suitable model system to study human neuronal connectivity is lacking. Here, we report a comprehensive and efficient differentiation paradigm for hiPSCs that generate multiple CA3 pyramidal neuron subtypes as detected by single-cell RNA sequencing (RNA-seq). This differentiation paradigm exhibits characteristics of neuronal network maturation, and rabies virus tracing revealed synaptic connections between stem cell-derived dentate gyrus (DG) and CA3 neurons in vitro recapitulating the neuronal connectivity within the hippocampus.

In vitro myelin formation using embryonic stem cells.

Myelination in the central nervous system is the process by which oligodendrocytes form myelin sheaths around the axons of neurons. Myelination enables neurons to transmit information more quickly and more efficiently and allows for more complex brain functions; yet, remarkably, the underlying mechanism by which myelination occurs is still not fully understood. A reliable in vitro assay is essential to dissect oligodendrocyte and myelin biology.

Expression and functional characterization of membrane-integrated mammalian corticotropin releasing factor receptors 1 and 2 in Escherichia coli.

Corticotropin-Releasing Factor Receptors (CRFRs) are class B1 G-protein-coupled receptors, which bind peptides of the corticotropin releasing factor family and are key mediators in the stress response. In order to dissect the receptors' binding specificity and enable structural studies, full-length human CRFR1α and mouse CRFR2β as well as fragments lacking the N-terminal extracellular domain, were overproduced in E. coli.

In vivo demonstration that alpha-synuclein oligomers are toxic.

The aggregation of proteins into oligomers and amyloid fibrils is characteristic of several neurodegenerative diseases, including Parkinson disease (PD). In PD, the process of aggregation of α-synuclein (α-syn) from monomers, via oligomeric intermediates, into amyloid fibrils is considered the disease-causative toxic mechanism. We developed α-syn mutants that promote oligomer or fibril formation and tested the toxicity of these mutants by using a rat lentivirus system to investigate loss of dopaminergic neurons in the substantia nigra.

Short Promoters in Viral Vectors Drive Selective Expression in Mammalian Inhibitory Neurons, but do not Restrict Activity to Specific Inhibitory Cell-Types.

Short cell-type specific promoter sequences are important for targeted gene therapy and studies of brain circuitry. We report on the ability of short promoter sequences to drive fluorescent protein expression in specific types of mammalian cortical inhibitory neurons using adeno-associated virus (AAV) and lentivirus (LV) vectors. We tested many gene regulatory sequences derived from fugu (Takifugu rubripes), mouse, human, and synthetic composite regulatory elements.

Retinoic acid regulation of the Mesp-Ripply feedback loop during vertebrate segmental patterning.

The Mesp bHLH genes play a conserved role during segmental patterning of the mesoderm in the vertebrate embryo by specifying segmental boundaries and anteroposterior (A-P) segmental polarity. Here we use a xenotransgenic approach to compare the transcriptional enhancers that drive expression of the Mesp genes within segments of the presomitic mesoderm (PSM) of different vertebrate species. We find that the genomic sequences upstream of the mespb gene in the pufferfish Takifugu rubripes (Tr-mespb) are able to drive segmental expression in transgenic Xenopus embryos while those from the Xenopus laevis mespb (Xl-mespb) gene drive segmental expression in transgenic zebrafish.