Knockout of the ING5 epigenetic regulator confirms roles in stem cell maintenance and tumor suppression in vivo.

INhibitor of Growth (ING1-5) proteins are epigenetic readers that target histone acetyltransferase (HAT) or histone deacetylase (HDAC) complexes to the H3K4Me3 mark of active transcription. ING5 targets Moz/Morf and HBO1 HAT complexes that alter acetylation of H3 and H4 core histones, affecting gene expression. Previous experiments in vitro indicated that ING5 functions to maintain stem cell character in normal and in cancer stem cells.

Novel AAV variants with improved tropism for human Schwann cells.

Gene therapies and associated technologies are transforming biomedical research and enabling novel therapeutic options for patients living with debilitating and incurable genetic disorders. The vector system based on recombinant adeno-associated viral vectors (AAVs) has shown great promise in recent clinical trials for genetic diseases of multiple organs, such as the liver and the nervous system. Despite recent successes toward the development of novel bioengineered AAV variants for improved transduction of primary human tissues and cells, vectors that can efficiently transduce human Schwann cells (hSCs) have yet to be identified.

Perineurial Window is Critical for Experimental Reverse End-to-Side Nerve Transfer.

Background: The depth of connective tissue window in the side of a recipient nerve in reverse end-to-side transfers (RETS) remains controversial.

Objective: To test whether the depth of connective tissue disruption influences the efficiency of donor axonal regeneration in the context of RETS.

Methods: Sprague-Dawley rats (n = 24) were assigned to 1 of the 3 groups for obturator nerve to motor femoral nerve RETS: group 1, without epineurium opening; group 2, with epineurium only opening; and group 3, with epineurium and perineurium opening.

A Multi-Stage Bioprocess for the Expansion of Rodent Skin-Derived Schwann Cells in Computer-Controlled Bioreactors.

Regenerative therapies for the treatment of peripheral nerve and spinal cord injuries can require hundreds of millions of autologous cells. Current treatments involve the harvest of Schwann cells (SCs) from nerves; however, this is an invasive procedure. Therefore, a promising alternative is using skin-derived Schwann cells (Sk-SCs), in which between 3-5 million cells can be harvested from a standard skin biopsy.

Behavioral and axon histomorphometric analyses after intraneural transplantation of human skin- and nerve-derived Schwann cells in nude rats.

Introduction/aims: We have recently isolated and expanded skin-derived Schwann cells (Sk-SCs) from human skin and showed that they are largely similar to nerve-derived Schwann cells (N-SCs). Here, we extend our investigation into functional assessments of the nude rats that received human Sk-SCs and N-SCs after intraneural delivery into crushed and decellularized tibial nerve in adult nude rats.

Methods: Sk-SCs, N-SCs, dermal fibroblasts, or control culture medium was injected into the crushed and decellularized tibial nerve using in situ repeated freeze-thaw cycles.

Functional Gait Assessment Using Manual, Semi-Automated and Deep Learning Approaches Following Standardized Models of Peripheral Nerve Injury in Mice.

Objective: To develop a standardized model of stretch−crush sciatic nerve injury in mice, and to compare outcomes of crush and novel stretch−crush injuries using standard manual gait and sensory assays, and compare them to both semi-automated as well as deep-learning gait analysis methods. Methods: Initial studies in C57/Bl6 mice were used to develop crush and stretch−crush injury models followed by histologic analysis. In total, 12 eight-week-old 129S6/SvEvTac mice were used in a six-week behavioural study.

Utilization of focused ultrasound for opening of the blood-nerve barrier.

. Focused ultrasound (FUS) use with and without microbubbles (MB) for investigation of the blood-nerve barrier (BNB) within the peripheral nervous system (PNS) has been performed in this study. We evaluate the feasibility of BNB opening in a rodent sciatic nerve model by direct vision FUS treatment and provide preliminary results of magnetic resonance guided FUS (MRgFUS).

Successful retrograde regeneration using a sensory branch for motor nerve transfer.

Objective: The objective of this study was to test whether regenerating motor axons from a donor nerve can travel in a retrograde fashion using sensory branches to successfully reinnervate a motor nerve end organ.

Methods: This study has two parts. In part I, rats (n = 30) were assigned to one of five groups for obturator nerve (ON)-to-femoral nerve transfer: group 1, ON-to-saphenous nerve (SN) distal stump; group 2, ON-to-SN proximal stump without femoral nerve proper (FNP) injury; group 3, ON-to-SN proximal stump with FNP crush injury; group 4, ON-to-SN proximal stump with FNP transection injury; and group 5, gold standard transfer, ON-to-motor femoral nerve (MFN) branch.

Comparison of human skin- and nerve-derived Schwann cells reveals many similarities and subtle genomic and functional differences.

Skin is an easily accessible tissue and a rich source of Schwann cells (SCs). Toward potential clinical application of autologous SC therapies, we aim to improve the reliability and specificity of our protocol to obtain SCs from small skin samples. As well, to explore potential functional distinctions between skin-derived SCs (Sk-SCs) and nerve-derived SCs (N-SCs), we used single-cell RNA-sequencing and a series of in vitro and in vivo assays.

Simultaneous Localized Brain Mild Hyperthermia and Blood-Brain Barrier Opening via Feedback-Controlled Transcranial MR-Guided Focused Ultrasound and Microbubbles.

Objective: Non-invasive methods to enhance drug delivery and efficacy in the brain have been pursued for decades. Focused ultrasound hyperthermia (HT) combined with thermosensitive therapeutics have been demonstrated promising in enhancing local drug delivery to solid tumors. We hypothesized that the presence of microbubbles (MBs) combined with transcranial MR-guided focused ultrasound (MRgFUS) could be used to reduce the ultrasound power required for HT while simultaneously increasing drug delivery by locally opening the blood-brain barrier (BBB).

Insights Into the Role and Potential of Schwann Cells for Peripheral Nerve Repair From Studies of Development and Injury.

Peripheral nerve injuries arising from trauma or disease can lead to sensory and motor deficits and neuropathic pain. Despite the purported ability of the peripheral nerve to self-repair, lifelong disability is common. New molecular and cellular insights have begun to reveal why the peripheral nerve has limited repair capacity.

Traumatic Injury Reduces Amyloid Plaque Burden in the Transgenic 5xFAD Alzheimer's Mouse Spinal Cord.

Background: Axonal injury has been implicated in the development of amyloid-β in experimental brain injuries and clinical cases. The anatomy of the spinal cord provides a tractable model for examining the effects of trauma on amyloid deposition.

Objective: Our goal was to examine the effects of axonal injury on plaque formation and clearance using wild type and 5xFAD transgenic Alzheimer's disease mice.

Comparative Behavioral Assessment of Lewis and Nude Rats after Peripheral Nerve Injury.

Cell therapy has shown potential in the field of peripheral nerve repair, and research using rodents is a critical and essential step toward clinical development of this approach. Traditionally, most experimental peripheral nerve injuries are conducted in inbred Lewis or outbred Sprague-Dawley strains. However, transplantation of xenogeneic cells such as human-derived cells typically triggers rejection in these animals.

Droplet Barcoding-Based Single Cell Transcriptomics of Adult Mammalian Tissues.

The analysis of single cell gene expression across thousands of individual cells within a tissue or microenvironment is a valuable tool for identifying cell composition, discrimination of functional states, and molecular pathways underlying observed tissue functions and animal behaviors. However, the isolation of intact, healthy single cells from adult mammalian tissues for subsequent downstream single cell molecular analysis can be challenging. This protocol describes the general processes and quality control checks necessary to obtain high-quality adult single cell preparations from the nervous system or skin that enabled subsequent unbiased single cell RNA sequencing and analysis.

The triple monoamine re-uptake inhibitor DOV 216,303 promotes functional recovery after spinal cord contusion injury in mice.

Serotonin, noradrenaline and dopamine are important neuromodulators for locomotion in the spinal cord. Disruption of descending axons after spinal cord injury resulted in reduction of excitatory and neuromodulatory inputs to spinal neurons for locomotion. Receptor agonists or reuptake inhibitors for these neuromodulators have been shown to be beneficial in incomplete spinal cord injury.

Axonal and myelinic pathology in 5xFAD Alzheimer's mouse spinal cord.

As an extension of the brain, the spinal cord has unique properties which could allow us to gain a better understanding of CNS pathology. The brain and cord share the same cellular components, yet the latter is simpler in cytoarchitecture and connectivity. In Alzheimer's research, virtually all focus is on brain pathology, however it has been shown that transgenic Alzheimer's mouse models accumulate beta amyloid plaques in spinal cord, suggesting that the cord possesses the same molecular machinery and conditions for plaque formation.

Fluorescent Phosphorus Dendrimer as a Spectral Nanosensor for Macrophage Polarization and Fate Tracking in Spinal Cord Injury.

Dendrimers and dendriplexes, highly branched synthetic macromolecules, have gained popularity as new tools for a variety of nanomedicine strategies due to their unique structure and properties. We show that fluorescent phosphorus dendrimers are well retained by bone marrow-derived macrophages and exhibit robust spectral shift in its emission in response to polarization conditions. Fluorescence properties of this marker can also assist in identifying macrophage presence and phenotype status at different time points after spinal cord injury.

Neural progenitor cell apoptosis and differentiation were affected by activated microglia in spinal cord slice culture.

Neural progenitor cell (NPC) transplantation offers great potential to treat spinal cord injury (SCI). NPCs may replace lost neurons or oligodendrocytes and act as a source of neurotrophic factors to support survival of remaining cells. However, their efficiency was limited by poor survival after transplantation, and they tended more to differentiate into astrocytes, but not neurons and oligodendrocytes.

Down-regulation of apurinic/apyrimidinic endonuclease 1 (APE1) in spinal motor neurones under oxidative stress.

Aim: Apurinic/apyrimidinic endonuclease 1 (APE1) is an intermediate enzyme in base excision repair which is important for removing damaged nucleotides under normal and pathological conditions. Accumulation of damaged bases causes genome instability and jeopardizes cell survival. Our study is to examine APE1 regulation under oxidative stress in spinal motor neurones which are vulnerable to oxidative insult.

Minocycline inhibited the pro-apoptotic effect of microglia on neural progenitor cells and protected their neuronal differentiation in vitro.

Neural progenitor cell (NPC) transplantation offers great potential to treat spinal cord injury (SCI), but their efficiency is limited by poor survival and neuronal differentiation after transplantation. In the injury site, microglia may become activated and participate in the inflammation reaction. In vitro studies indicated that activated microglia might impair NPC survival and neuronal differentiation, but resting microglia did not.

Co-expression of GAP-43 and nNOS in avulsed motoneurons and their potential role for motoneuron regeneration.

Neuronal nitric oxide synthase (nNOS) is induced after axonal injury. The role of induced nNOS in injured neurons is not well established. In the present study, we investigated the co-expression of nNOS with GAP-43 in spinal motoneurons following axonal injury.

Induction of c-Jun phosphorylation in spinal motoneurons in neonatal and adult rats following axonal injury.

This study aims to address if phosphorylation of the transcription factor c-Jun is associated with lesion-induced death of spinal motoneurons, and if this cellular response is modulated by glial-cell-line-derived neurotrophic factor (GDNF). We found that after both distal axotomy and root avulsion, spinal motoneurons in neonatal rats expressed phosphorylated c-Jun (p-c-Jun) and almost all injured motoneurons in these animals died. Similarly, root avulsion in adult rats also induced p-c-Jun expression that preceded the loss of motoneurons.

Neurotrophic factor treatment after spinal root avulsion injury.

Spinal root avulsion injury causes motoneuron death and immediate loss of sensory and motor functions. Surgical intervention such as reimplantation of avulsed root is proven useful to restore neural circuitry of spinal cord and targeted muscles. Yet, additional strategies are required for faster and better functional recovery which is overall unsatisfactory.

Implantation of neurotrophic factor-treated sensory nerve graft enhances survival and axonal regeneration of motoneurons after spinal root avulsion.

We previously showed that motor nerves are superior to sensory nerves in promoting axon regeneration after spinal root avulsion. It is, however, impractical to use motor nerves as grafts. One potential approach to enhancing axonal regeneration using sensory nerves is to deliver trophic factors to the graft.