We grafted human spinal cord-derived neural progenitor cells (NPCs) into sites of cervical spinal cord injury in rhesus monkeys (Macaca mulatta). Under three-drug immunosuppression, grafts survived at least 9 months postinjury and expressed both neuronal and glial markers. Monkey axons regenerated into grafts and formed synapses. Hundreds of thousands of human axons extended out from grafts through monkey white matter and synapsed in distal gray matter. Grafts gradually matured over 9 months and improved forelimb function beginning several months after grafting. These findings in a 'preclinical trial' support translation of NPC graft therapy to humans with the objective of reconstituting both a neuronal and glial milieu in the site of spinal cord injury.

Inhibitory extracellular matrices form around mature neurons as perineuronal nets containing chondroitin sulfate proteoglycans (CSPGs) that limit axonal sprouting after CNS injury. The enzyme chondroitinase (Chase) degrades the inhibitory CSPGs and improves axonal sprouting and functional recovery after spinal cord injury (SCI) in rodents. We evaluated the effects of Chase in Rhesus monkeys that had undergone C7 spinal cord hemisection. Four weeks after hemisection, multiple intraparenchymal Chase injections targeted spinal cord circuits controlling hand function below the lesion. Hand function improved significantly in Chase-treated monkeys relative to vehicle-injected controls. Moreover, Chase significantly increased corticospinal axon growth and the number of synapses formed by corticospinal terminals in gray matter caudal to the lesion. No detrimental effects were detected. This approach appears to merit clinical translation in SCI.

Structural changes in pre and postsynaptic neurons that accompany synapse formation often temporally and spatially overlap. Thus, it has been difficult to resolve which processes drive patterned connectivity. To overcome this, we use the laminated outer murine retina. We identify the serine/threonine kinase LKB1 as a key driver of synapse layer emergence. The absence of LKB1 in the retina caused a marked mislocalization and delay in synapse layer formation. In parallel, LKB1 modulated postsynaptic horizontal cell refinement and presynaptic photoreceptor axon growth. Mislocalized horizontal cell processes contacted aberrant cone axons in LKB1 mutants. These defects coincided with altered synapse protein organization, and horizontal cell neurites were misdirected to ectopic synapse protein regions. Together, these data suggest that LKB1 instructs the timing and location of connectivity in the outer retina via coordinate regulation of pre and postsynaptic neuron structure and the localization of synapse-associated proteins.

Isotopologues are valuable vibrational probes that shift features in a vibrational spectrum while preserving the electronic structure of the molecule. We report the vibrational and electronic spectra of perdeuterated tryptophan in solution (l-Trp-d 5), as Trp48-d 5 in azurin, and as the photogenerated neutral tryptophan radical, Trp48-d 5 •, in azurin. The UV resonance Raman bands of the perdeuterated closed-shell tryptophan in solution and in azurin are lower in frequency relative to the protiated counterpart. The observed decrease in frequencies of l-Trp-d 5 bands relative to l-Trp-h 5 enables the analysis of vibrational markers of other amino acids, e.g., phenylalanine, that overlap with some modes of l-Trp-h 5. The Raman intensities vary between l-Trp-d 5 and l-Trp-h 5; these differences likely reflect modifications in normal mode composition upon perdeuteration. Analysis of the W3, W6, and W17 modes suggests that the W3 mode retains its utility as a conformational marker; however, the H-bond markers W6 and W17 appear to be less sensitive upon perdeuteration. The neutral tryptophan radical, Trp48-d 5 •, was generated in azurin with a slightly lower radical quantum yield than for Trp48-h 5 •. The visible resonance Raman spectrum of Trp48-d 5 • is different from that of Trp48-h 5 •, especially in terms of relative intensities, and all assignable peaks decreased in frequency upon perdeuteration. The absorption and emission spectra of the perdeuterated closed-shell and radical species exhibited hypsochromic shifts of less than 1 nm relative to the protiated species. The data presented here indicate that l-Trp-d 5 is a valuable probe of vibrational structure, with minimal modification of photoreactivity and photophysics compared to l-Trp-h 5.

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SUMMARY Cone photoreceptors detect light and are responsible for color vision. These cells display a distinct polarized morphology where nuclei are precisely aligned in the apical retina. However, little is known about the mechanisms involved in cone nuclear positioning or the impact of this organization on retina function. We show that the serine/threonine kinase LKB1 and one of its substrates, AMPK, regulate cone nuclear positioning. In the absence of either molecule, cone nuclei are misplaced along the axon, resulting in altered nuclear lamination. LKB1 is required specifically in cones to mediate this process, and disruptions in nuclear alignment result in reduced cone function. Together, these results identify molecular determinants of cone nuclear position and indicate that cone nuclear position alignment enables proper visual function.

BackgroundResuscitation for traumatic cardiac arrest (TCA) in patients with severe traumatic brain injury (sTBI) has historically been considered futile. There is little information on the characteristics and outcomes of these patients to guide intervention and prognosis. The purpose of the current study is to report the clinical characteristics, survival, and long-term neurological outcomes in patients who experienced TCA after sTBI and analyze the factors contributing to survival.MethodsA retrospective review identified 42 patients with TCA from a total of 402 patients with sTBI (Glasgow Coma Scale (GCS) score ≤8) who were admitted to Stony Brook University Hospital, a level I trauma center, from January 2011 to December 2018. Patient demographics, clinical characteristics, survival, and neurological functioning during hospitalization and at follow-up visits were collected.ResultsOf the 42 patients, the average age was 45 years and 21.4% were female. Eight patients survived the injury (19.0%) to discharge and seven survived with good neurological function. Admission GCS score and bilateral pupil reactivity were found to be significant indicators of survival. The mean GCS score was 5.3 in survivors and 3.2 in non-survivors (p=0.020). Age, Injury Severity Score, or cardiac rhythm was not associated with survival. Frequent neuroimaging findings included subarachnoid hemorrhage, subdural hematoma, and diffuse axonal injury.DiscussionTCA after sTBI is survivable and seven out of eight patients in our study recovered with good neurological function. GCS score and pupil reactivity are the best indicators of survival. Our results suggest that due to the possibility of recovery, resuscitation and neurosurgical care should not be withheld from this patient population.Level of evidenceLevel IV, therapeutic/care management.

Mutations in the potassium channel tetramerization domain-containing 7 (KCTD7) gene are associated with a severe neurodegenerative phenotype characterized by childhood onset of progressive and intractable myoclonic seizures accompanied by developmental regression. Kctd7 (EPM3) is a member of a large family of progressive myoclonic epilepsy (EPM) syndromes displaying a broad spectrum of clinical severity. Animal models of Kctd7-related disease are lacking, and little is known regarding how Kctd7 protein defects lead to epilepsy and cognitive dysfunction. We characterized brain Kctd7 expression patterns during development and show it is selectively enriched in specific regions as the brain matures. We further demonstrate that Kctd7-deficient mice develop seizures and locomotor defects with features similar to those observed in human KCTD7-associated disease. We also show that Kctd7 is required for Purkinje cell survival in the cerebellum and that selective degeneration of these neurons is accompanied by defects in cerebellar brain microvascular organization and patterning. Together, these results define a new model for Kctd7- associated epilepsy and identify Kctd7 as a modulator of neuron survival and excitability linked to microvascular alterations in vulnerable regions.