Preparation for the Future: The Impact of OT Programming on Adolescents With Developmental and Learning Disabilities

Date Presented Accepted for AOTA INSPIRE 2021 but unable to be presented due to online event limitations. OTs, residency, and fieldwork students implemented targeted group programming at area high schools to address functional transition needs for individuals with developmental and learning disabilities to prepare them for life after high school. The needs unique to these students at this critical life transition, the challenges experienced when providing services to these populations, and the current methods used to assess and document outcomes will be discussed. Primary Author and Speaker: Jennifer A. Merz Additional Authors and Speakers: Bonnie Nakasuji Contributing Authors: Kimberly Mollo

Ultrastructure expansion microscopy of Plasmodium gametocytes reveals the molecular architecture of a microtubule organisation centre coordinating mitosis with axoneme assembly

The transmission of malaria-causing parasites to mosquitoes relies on the production of the gametocyte stages and their development into gametes upon a blood feed. These stages display various microtubule cytoskeletons and the architecture of the corresponding microtubule organisation centres (MTOC) remains elusive. Combining ultrastructure expansion microscopy (U-ExM) with bulk proteome labelling, we first reconstructed in 3D the subpellicular microtubule network and its associated actin cytoskeleton, which confer cell rigidity to Plasmodium falciparum gametocytes. Upon activation, as the microgametocyte undergoes three rounds of endomitosis, it simultaneously assembles axonemes to form eight flagellated microgametes. Here, U-ExM combined with Pan-ExM revealed the molecular architecture of a single bipartite MTOC coordinating mitosis with axoneme formation. This MTOC spans the nuclear membrane linking acentriolar mitotic plaques to cytoplasmic basal bodies by proteinaceous filaments. The eight basal bodies are concomitantly de novo assembled from a deuterosome-like structure, where centrin, γ-tubulin, SAS4/CPAP and SAS6 form distinct subdomains. Once assembled, the basal bodies show a fusion of the proximal and central cores where colocalised centrin and SAS6 are surrounded by a SAS4/CPAP-toroid in the lumen of the microtubule wall. Sequential nucleation of axonemes and mitotic spindles is associated with a dynamic movement of γ-tubulin from the basal bodies to the acentriolar plaques. We finally show that this atypical MTOC architecture relies on two non-canonical MTOC regulators, the calcium-dependent protein kinase 4 and the serine/arginine-protein kinase 1. Altogether, these results provide insights into the molecular organisation of a bipartite MTOC that may reflect a functional transition of a basal body to coordinate axoneme formation with mitosis.

Supervised Capacity Preserving Mapping: A Clustering Guided Visualization Method for scRNAseq data

The rapid development of scRNA-seq technologies enables us to explore the transcriptome at the cell level in a large scale. Recently, various computational methods have been developed to analyze the scRNAseq data such as clustering and visualization. However, current visualization methods including t-SNE and UMAP are challenged by the limited accuracy of rendering the geometic relationship of populations with distinct functional states. Most visualization methods are unsupervised, leaving out information from the clustering results or given labels. This leads to the inaccurate depiction of the distances between the bona fide functional states. In particular, UMAP and t-SNE are not optimal to preserve the global geometric structure. They may result in a contradiction that clusters with near distance in the embedded dimensions are in fact further away in the original dimensions. Besides, UMAP and t-SNE cannot track the variance of clusters. Through the embedding of t-SNE and UMAP, the variance of a cluster is not only associated with the true variance but also is proportional to the sample size. We present supCPM, a robust supervised visualization method, which separates different clusters, preserves global structure, and tracks the cluster variance. Compared with six visualization methods using synthetic and real datasets, supCPM shows improved performance than other methods in preserving the global geometric structure and data variance. Overall, supCPM provides an enhanced visualization pipeline to assist the interpretation of functional transition and accurately depict population segregation.

Balancing the length of distal tip is key for stability and signalling function of primary cilia

Primary cilia are antenna-like organelles required for signalling transduction. How cilia structure is mechanistically maintained at steady-state to promote signalling is largely unknown. Here, we define that mammalian primary cilia are formed by middle and distal segments, in analogy to sensory cilia of lower eukaryotes. The analysis of middle/distal segmentation indicated that perturbations leading to cilia over-elongation influenced middle or distal segment length with a different impact on cilia behaviour. We identified Septins as novel repressors of distal segment growth. We show that Septins control the localisation of MKS3 and CEP290 required for a functional transition zone, and through this the entrance of the microtubule-capping kinesin KIF7, a cilia-growth inhibitor, into the cilium. Live-cell imaging and analysis of sonic-hedgehog (SHH) signalling activation established that distal segment over-extension increased cilia excision events and decreased SHH activation. Our data underlies the importance of understanding cilia segmentation for length control and cilia-dependent signalling.

The neurogenic fate of the hindbrain boundaries: a Notch-dependent behavioral switch triggers asymmetric division of boundary stem cells

The generation of cell diversity in the central nervous system occurs during embryogenesis and requires a precise balance between stem cell proliferation, neuronal commitment to specific fates, and further differentiation. Understanding the cellular and molecular mechanisms regulating this balance in the embryonic brain is challenging. Here we reveal how the neurogenic capacity in the hindbrain is differently allocated to distinct domains over time, and how the boundary cells undergo a functional transition to become neurogenic during zebrafish hindbrain segmentation. By generating a CRISPR-based knock-in transgenic line to specifically label the boundary cell population, we tracked their derivatives over time and followed their behavior, allowing us to identify how asymmetric cell divisions arise and to reconstruct the trajectories of the boundary derivatives through the progenitor and differentiated domains. The behavioral switch in boundary cells is triggered by the onset of Notch signaling, based on lateral inhibition at the dorsoventral level. Our findings reveal that distinct neurogenic phases take place during hindbrain growth and suggest that boundary cells contribute to refine the final number, identity, and proportion of neurons in the brain.

Exceptional multifunctionality in the feeding apparatus of a mid-Cambrian radiodont

Radiodonts (stem Euarthropoda) were ecologically diverse, but species generally displayed limited functional specialization of appendages along the body axis compared with crown group euarthropods. This is puzzling, because such functional specialization is considered to have been an important driver of euarthropod ecological diversification. One way to circumvent this constraint could have been the functional specialization of different parts of the frontal appendages, known to have been ecologically important in radiodonts. This hypothesis has yet to be tested explicitly. Here we redescribe the poorly known mid-Cambrian hurdiid radiodont Stanleycaris hirpex from the Burgess Shale (Stephen Formation) and quantitatively assess functional specialization of the frontal appendages of stem euarthropods. The appendages of Stanleycaris are composed of 14 podomeres, variously differentiated by their possession of pectinate endites, mono- to trifurcate medial gnathites, and outer spines. The oral cone is tetraradially organized and can be uniquely distinguished from those of other hurdiids by the presence of 28 rather than 32 smooth tridentate plates. Our phylogenetic analysis finds Stanleycaris in a grade of hurdiids retaining plesiomorphic raptorial appendicular functionality alongside derived adaptations for sweep feeding and large, bilaterally opposed gnathites. We conclude that the latter performed a masticatory function, convergent with gnathal structures like mandibles in various panarthropods. Taken together, Stanleycaris and similar hurdiids provide an extreme example of the evolution of division of labor within the appendage of a stem euarthropod and suggest that this innovation may have facilitated the functional transition, from raptorial to sweep feeding, at the origin of the hurdiid clade.

Running and Swimming Differently Adapt the BDNF/TrkB Pathway to a Slow Molecular Pattern at the NMJ

Physical exercise improves motor control and related cognitive abilities and reinforces neuroprotective mechanisms in the nervous system. As peripheral nerves interact with skeletal muscles at the neuromuscular junction, modifications of this bidirectional communication by physical activity are positive to preserve this synapse as it increases quantal content and resistance to fatigue, acetylcholine receptors expansion, and myocytes’ fast-to-slow functional transition. Here, we provide the intermediate step between physical activity and functional and morphological changes by analyzing the molecular adaptations in the skeletal muscle of the full BDNF/TrkB downstream signaling pathway, directly involved in acetylcholine release and synapse maintenance. After 45 days of training at different intensities, the BDNF/TrkB molecular phenotype of trained muscles from male B6SJLF1/J mice undergo a fast-to-slow transition without affecting motor neuron size. We provide further knowledge to understand how exercise induces muscle molecular adaptations towards a slower phenotype, resistant to prolonged trains of stimulation or activity that can be useful as therapeutic tools.

Interferon-Mediated Long Non-Coding RNA Response in Macrophages in the Context of HIV

Interferons play a critical role in the innate immune response against a variety of pathogens, such as HIV-1. Recent studies have shown that long non-coding genes are part of a reciprocal feedforward/feedback relationship with interferon expression. They presumably contribute to the cell type specificity of the interferon response, such as the phenotypic and functional transition of macrophages throughout the immune response. However, no comprehensive understanding exists today about the IFN–lncRNA interplay in macrophages, also a sanctuary for latent HIV-1. Therefore, we completed a poly-A+ RNAseq analysis on monocyte-derived macrophages (MDMs) treated with members of all three types of IFNs (IFN-α, IFN-ε, IFN-γ or IFN-λ) and on macrophages infected with HIV-1, revealing an extensive non-coding IFN and/or HIV-1 response. Moreover, co-expression correlation with mRNAs was used to identify important (long) non-coding hub genes within IFN- or HIV-1-associated gene clusters. This study identified and prioritized IFN related hub lncRNAs for further functional validation.

Asaronic Acid Inhibited Glucose-Triggered M2-Phenotype Shift Through Disrupting the Formation of Coordinated Signaling of IL-4Rα-Tyk2-STAT6 and GLUT1-Akt-mTOR-AMPK

Macrophage polarization has been implicated in the pathogenesis of metabolic diseases such as obesity, diabetes, and atherosclerosis. Macrophages responsiveness to polarizing signals can result in their functional phenotype shifts. This study examined whether high glucose induced the functional transition of M2 macrophages, which was inhibited by asaronic acid, one of purple perilla constituents. J774A.1 murine macrophages were incubated with 40 ng/mL interleukin (IL)-4 or exposed to 33 mM glucose in the presence of 1-20 μΜ asaronic acid. In macrophages treated with IL-4 for 48 h, asaronic acid further accelerated cellular induction of the M2 markers of IL-10, arginase-1, CD163, and PPARγ via increased IL-4-IL-4Rα interaction and activated Tyk2-STAT6 pathway. Asaronic acid promoted angiogenic and proliferative capacity of M2-polarized macrophages, through increasing expression of VEGF, PDGF, and TGF-β. In glucose-loaded macrophages, there was cellular induction of IL-4, IL-4 Rα, arginase-1, and CD163, indicating that high glucose skewed naïve macrophages toward M2 phenotypes via an IL-4-IL-4Rα interaction. However, asaronic acid inhibited M2 polarization in diabetic macrophages in parallel with inactivation of Tyk2-STAT6 pathway and blockade of GLUT1-mediated metabolic pathway of Akt-mTOR-AMPKα. Consequently, asaronic acid deterred functional induction of COX-2, CTGF, α-SMA, SR-A, SR-B1, and ABCG1 in diabetic macrophages with M2 phenotype polarity. These results demonstrated that asaronic acid allayed glucose-activated M2-phenotype shift through disrupting coordinated signaling of IL-4Rα-Tyk2-STAT6 in parallel with GLUT1-Akt-mTOR-AMPK pathway. Thus, asaronic acid has therapeutic potential in combating diabetes-associated inflammation, fibrosis, and atherogenesis through inhibiting glucose-evoked M2 polarization.