Bipolar spindle assembly is a critical control point for initiation of mitosis through nucleation and organization of spindle microtubules and is regulated by kinesin-like proteins. In fission yeast, the kinesin-14 Pkl1 binds the γ-tubulin ring complex (γ-TuRC) microtubule-organizing centre at spindle poles and can alter its structure and function. Here we show that kinesin-14 blocks microtubule nucleation in yeast and reveal that this inhibition is countered by the kinesin-5 protein, Cut7. Furthermore, we demonstrate that Cut7 binding to γ-TuRC and the Cut7 BimC domain are both required for inhibition of Pkl1. We also demonstrate that a yeast kinesin-14 peptide blocks microtubule nucleation in two human breast cancer cell lines, suggesting that this mechanism is evolutionarily conserved. In conclusion, using genetic, biochemical and cell biology approaches we uncover antagonistic control of microtubule nucleation at γ-TuRC by two kinesin-like proteins, which may represent an attractive anti-mitotic target for cancer therapies.

Stem cell technologies including self-assembling 3D tissue models provide access to early human neurodevelopment and fundamental insights into neuropathologies. Gastruloid models have not been used to investigate co-developing central and peripheral neuronal systems with trunk mesendoderm which we achieve here in elongating multi-lineage organized (EMLO) gastruloids. We evaluate EMLOs over a forty-day period, applying immunofluorescence of multi-lineage and functional biomarkers, including day 16 single-cell RNA-Seq, and evaluation of ectodermal and non-ectodermal neural crest cells (NCCs). We identify NCCs that differentiate to form peripheral neurons integrated with an upstream spinal cord region after day 8. This follows initial EMLO polarization events that coordinate with endoderm differentiation and primitive gut tube formation during multicellular spatial reorganization. This combined human central-peripheral nervous system model of early organogenesis highlights developmental events of mesendoderm and neuromuscular trunk regions and enables systemic studies of tissue interactions and innervation of neuromuscular, enteric and cardiac relevance.

The human genome with all its ethnic variations contributes to differences in human development, aging, disease, repair, and response to medical treatments and is an exciting area of research and clinical study. The availability of well-characterized ethnically diverse stem cell lines is limited and has not kept pace with other advances in stem cell research. Here we derived xenofree ethnically diverse-human induced pluripotent stem cell (ED-iPSC) lines from fibroblasts obtained from individuals of African American, Hispanic-Latino, Asian, and Caucasian ethnic origin and have characterized the lines under a uniform platform for comparative analysis. Derived ED-iPSC lines are low passage number and evaluated in vivo by teratoma formation and in vitro by high throughput microarray analysis of EB formation and early differentiation for tri-lineage commitment to endoderm, ectoderm and mesoderm. These new xenofree ED-iPSC lines represent a well-characterized valuable resource with potential for use in future research in drug discovery or clinical investigations.

The γ-tubulin ring complex (γ-TuRC) is a key part of microtubule-organizing centers (MTOCs) that control microtubule polarity, organization and dynamics in eukaryotes. Understanding regulatory mechanisms of γ-TuRC function is of fundamental importance, as this complex is central to many cellular processes, including chromosome segregation, fertility, neural development, T-cell cytotoxicity and respiration. The fission yeast microtubule motor kinesin-14 Pkl1 regulates mitosis by binding to the γ-tubulin small complex (γ-TuSC), a subunit of γ-TuRC. Here we investigate the binding mechanism of Pkl1 to γ-TuSC and its functional consequences using genetics, biochemistry, peptide assays and cell biology approaches in vivo and in vitro. We identify two critical elements in the Tail domain of Pkl1 that mediate γ-TuSC binding and trigger release of γ-tubulin from γ-TuRC. Such action disrupts the MTOC and results in failed mitotic spindle assembly. This study is the first demonstration that a motor protein directly affects the structural composition of the γ-TuRC, and we provide details of this mechanism that may be of broad biological importance.

The realization of personalized medicine through human induced pluripotent stem cell (iPSC) technology can be advanced by transcriptomics, epigenomics, and bioinformatics that inform on genetic pathways directing tissue development and function. When possible, population diversity should be included in new studies as resources become available. Previously we derived replicate iPSC lines of African American, Hispanic-Latino and Asian self-designated ethnically diverse (ED) origins with normal karyotype, verified teratoma formation, pluripotency biomarkers, and tri-lineage in vitro commitment. Here we perform bioinformatics of RNA-Seq and ChIP-seq pluripotency data sets for two replicate Asian and Hispanic-Latino ED-iPSC lines that reveal differences in generation of contractile cardiomyocytes but similar and robust differentiation to multiple neural, pancreatic, and smooth muscle cell types. We identify shared and distinct genes and contributing pathways in the replicate ED-iPSC lines to enhance our ability to understand how reprogramming to iPSC impacts genes and pathways contributing to cardiomyocyte contractility potential.

cell therapy for the injured spinal cord will rely on combined advances in human stem cell technologies and delivery strategies. Here we encapsulate homotypic spinal cord neural stem cells (scnScs) in an alginate-based neural ribbon delivery platform. We perform a comprehensive in vitro analysis and qualitatively demonstrate graft survival and injury site retention using a rat C4 hemi-contusion model. Pre-configured neural ribbons are transport-stable modules that enable site-ready injection, and can support scNSC survival and retention in vivo. Neural ribbons offer multifunctionality in vitro including co-encapsulation of the injury site extracellular matrix modifier chondroitinase ABC (chABC), tested here in glial scar models, and ability of cervically-patterned scNSCs to differentiate within neural ribbons and project axons for integration with 3-D external matrices. This is the first extensive in vitro characterization of neural ribbon technology, and constitutes a plausible method for reproducible delivery, placement, and retention of viable neural cells in vivo.

No abstract

Objective Generator site pain is a relatively common phenomenon in patients undergoing spinal cord stimulation (SCS) that complicates management and effective pain relief. This pain may be managed conservatively, with repositioning of the battery and in some cases with explant. Here we explore our experience with management of generator site pain (‘pocket pain’) in a large single-center study. Methods All SCS permanent implants and implantable pulse generator (IPG) placements over 9 years were reviewed. Of 785 cases, we identified 43 patients with pocket pain (5.5%). Demographics and treatments of the pocket pain cohort were analyzed. Results The mean age (± SEM) of the pocket pain cohort was 46.86 ± 1.06 and there were 10/33 males/females. Females were overrepresented in pocket pain cohort (76.7%) when compared to the total SCS cohort (59.0%) (X2 = 5.93, p = 0.015). Diagnosis included failed back surgery syndrome (51.2%), complex regional pain syndrome (23.3%), and chronic neuropathic pain (25.5%). No patients improved with conservative therapy. All patients either went on to revision (n = 23) or explant (n = 20). Time from initial surgery to development of pocket pain was 7.5 months (range: 0.3-88) and from pocket pain to revision surgery was 4.5 months (range: 0.4-26). In addition, significantly more pocket pain patients (65.1%) had workers’ compensation (WC) insurance compared to patients without pocket pain (24.9%) (X2 = 33.3, p < 0.001). Conclusion In our institutional experience, pocket pain was inadequately managed with conservative treatments. Being female and having SCS filed under WC increased risk of pocket pain. Future work will explore the nuances in device placement based on body shape and manual activity responsibilities.