Cyclic AMP Signaling: A Molecular Determinant of Peripheral Nerve Regeneration

Disruption of axonal integrity during injury to the peripheral nerve system (PNS) sets into motion a cascade of responses that includes inflammation, Schwann cell mobilization, and the degeneration of the nerve fibers distal to the injury site. Yet, the injured PNS differentiates itself from the injured central nervous system (CNS) in its remarkable capacity for self-recovery, which, depending upon the length and type of nerve injury, involves a series of molecular events in both the injured neuron and associated Schwann cells that leads to axon regeneration, remyelination repair, and functional restitution. Herein we discuss the essential function of the second messenger, cyclic adenosine monophosphate (cyclic AMP), in the PNS repair process, highlighting the important role the conditioning lesion paradigm has played in understanding the mechanism(s) by which cyclic AMP exerts its proregenerative action. Furthermore, we review the studies that have therapeutically targeted cyclic AMP to enhance endogenous nerve repair

Chronic thoracic hemisection spinal cord injury in adult rats induces a progressive decline in transmission from uninjured fibers to lumbar motoneurons

Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and extracellular recordings at L5 (below HX) in response to electrical stimulation of contralateral white matter above (T6) and below (L1) HX. Responses from T6 displayed reduced amplitude, increased latency and elevated stimulus threshold in the fibers across from HX, beginning 1-2 weeks after HX. Ultrastructural analysis revealed demyelination of intact axons contralateral to the HX, with a time course similar to the conduction changes. Behavioral studies indicated partial recovery which arrested when conduction deficits began. These findings suggest a chronic pathological state in intact fibers and necessity for prompt treatment to minimize it

A selective phosphodiesterase-4 inhibitor reduces leukocyte infiltration, oxidative processes, and tissue damage after spinal cord injury

We tested the hypothesis that a selective phosphodiesterase type 4 inhibitor (PDE4-I; IC486051) would attenuate early inflammatory and oxidative processes following spinal cord injury (SCI) when delivered during the first 3 days after injury. Rats receiving a moderately severe thoracic-clip-compression SCI were treated with the PDE4-I (0.5, 1.0, and 3.0 mg/kg IV) in bolus doses from 2-60 h post-injury. Doses at 0.5 mg/kg and 1.0 mg/kg significantly decreased myeloperoxidase (MPO) enzymatic activity (neutrophils), expression of a neutrophil-associated protein and of ED-1 (macrophages), and estimates of lipid peroxidation in cord lesion homogenates at 24 h and 72 h post-injury by 25-40%. The 3.0 mg/kg dose had small or no effects on these measures. The PDE4-I treatment (0.5 or 1.0 mg/kg) reduced expression of the oxidative enzymes gp91phox, inducible nitric oxide synthase, and cyclooxygenase-2, and diminished free radical generation by up to 40%. Treatment with 0.5 mg/kg PDE4-I improved motor function (as assessed by the Basso-Beattie-Bresnahan scale) significantly from 4-8 weeks after SCI (average difference 1.3 points). Mechanical allodynia elicited from the hindpaw decreased by up to 25%. The PDE4-I treatment also increased white matter volume near the lesion at 8 weeks after SCI. In conclusion, the PDE4-I reduced key markers of oxidative stress and leukocyte infiltration, producing cellular protection, locomotor improvements, and a reduction in neuropathic pain. Early inhibition of PDE4 is neuroprotective after SCI when given acutely and briefly at sufficient doses. © 2011, Mary Ann Liebert, Inc

The Use of Antisense-Mediated Inhibition to Delineate The Role of Inflammatory Agents in The Pathophysiology of Spinal Cord Injury

Injuries to the central nervous system (CNS) usually lead to a potent and acute inflammatory response[1]. During this period, glia and immune cells respond to chemical cues associated with the debris of lysed neurons, disrupted axons, and a broken blood-brain-barrier by releasing a battery of cytokines including tumor necrosis factor-α (TNF-α) and, interleukin-β (IL-1β) as well as reactive oxygen species such as nitric oxide (NO-)[2]. The secretion of these factors may be primarily responsible for secondary damage to surrounding uninjured tissue that potentiates the initial injury[3]. Antisense oligonucleotides (ASOs) are designed to hybridize to specific regions of specific mRNAs. Hybridization of the oligonucleotide to the mRNA then interferes with the normal processing of that mRNA at the ribosome or targets the RNA duplex for cleavage by the RNA digestive enzyme, ribonuclease H, resulting in greatly reduced expression of the coded protein. This effectively reduces the amount of corresponding translated protein product and experiments can be designed to examine the requirement of particular inflammatory agents in eliciting specific deleterious responses after injury, e.g., cell death

Acute Putrescine Supplementation with Schwann Cell Implantation Improves Sensory and Serotonergic Axon Growth and Functional Recovery in Spinal Cord Injured Rats

Schwann cell (SC) transplantation exhibits significant potential for spinal cord injury (SCI) repair and its use as a therapeutic modality has now progressed to clinical trials for subacute and chronic human SCI. Although SC implants provide a receptive environment for axonal regrowth and support functional recovery in a number of experimental SCI models, axonal regeneration is largely limited to local systems and the behavioral improvements are modest without additional combinatory approaches. In the current study we investigated whether the concurrent delivery of the polyamine putrescine, started either 30 min or 1 week after SCI, could enhance the efficacy of SCs when implanted subacutely (1 week after injury) into the contused rat spinal cord. Polyamines are ubiquitous organic cations that play an important role in the regulation of the cell cycle, cell division, cytoskeletal organization, and cell differentiation. We show that the combination of putrescine with SCs provides a significant increase in implant size, an enhancement in axonal (sensory and serotonergic) sparing and/or growth, and improved open field locomotion after SCI, as compared to SC implantation alone. These findings demonstrate that polyamine supplementation can augment the effectiveness of SCs when used as a therapeutic approach for subacute SCI repair

Central but not systemic administration of XPro1595 is therapeutic following moderate spinal cord injury in mice

BACKGROUND: Glial cell activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in acute traumatic injuries to the CNS, including spinal cord injury (SCI). Elevated levels of the proinflammatory cytokine tumor necrosis factor (TNF), which exists in both a soluble (sol) and a transmembrane (tm) form, have been found in the lesioned cord early after injury. The contribution of solTNF versus tmTNF to the development of the lesion is, however, still unclear. METHODS: We tested the effect of systemically or centrally blocking solTNF alone, using XPro1595, versus using the drug etanercept to block both solTNF and tmTNF compared to a placebo vehicle following moderate SCI in mice. Functional outcomes were evaluated using the Basso Mouse Scale, rung walk test, and thermal hyperalgesia analysis. The inflammatory response in the lesioned cord was investigated using immunohistochemistry and western blotting analyses. RESULTS: We found that peripheral administration of anti-TNF therapies had no discernable effect on locomotor performances after SCI. In contrast, central administration of XPro1595 resulted in improved locomotor function, decreased anxiety-related behavior, and reduced damage to the lesioned spinal cord, whereas central administration of etanercept had no therapeutic effects. Improvements in XPro1595-treated mice were accompanied by increases in Toll-like receptor 4 and TNF receptor 2 (TNFR2) protein levels and changes in Iba1 protein expression in microglia/macrophages 7 and 28 days after SCI. CONCLUSIONS: These studies suggest that, by selectively blocking solTNF, XPro1595 is neuroprotective when applied directly to the lesioned cord. This protection may be mediated via alteration of the inflammatory environment without suppression of the neuroprotective effects of tmTNF signaling through TNFR2

Acute delivery of EphA4-Fc improves functional recovery after contusive spinal cord injury in rats

Blocking the action of inhibitory molecules at sites of central nervous system injury has been proposed as a strategy to promote axonal regeneration and functional recovery. We have previously shown that genetic deletion or competitive antagonism of EphA4 receptor activity promotes axonal regeneration and functional recovery in a mouse model of lateral hemisection spinal cord injury. Here we have assessed the effect of blocking EphA4 activation using the competitive antagonist EphA4-Fc in a rat model of thoracic contusive spinal cord injury. Using a ledged tapered balance beam and open-field testing, we observed significant improvements in recovery of locomotor function after EphA4-Fc treatment. Consistent with functional improvement, using high-resolution ex vivo magnetic resonance imaging at 16.4T, we found that rats treated with EphA4-Fc had a significantly increased cross-sectional area of the dorsal funiculus caudal to the injury epicenter compared with controls. Our findings indicate that EphA4-Fc promotes functional recovery following contusive spinal cord injury and provides further support for the therapeutic benefit of treatment with the competitive antagonist in acute cases of spinal cord injury

Identifying the Long-Term Role of Inducible Nitric Oxide Synthase after Contusive Spinal Cord Injury Using a Transgenic Mouse Model

Inducible nitric oxide synthase (iNOS) is a potent mediator of oxidative stress during neuroinflammation triggered by neurotrauma or neurodegeneration. We previously demonstrated that acute iNOS inhibition attenuated iNOS levels and promoted neuroprotection and functional recovery after spinal cord injury (SCI). The present study investigated the effects of chronic iNOS ablation after SCI using inos-null mice. iNOS−/− knockout and wild-type (WT) control mice underwent a moderate thoracic (T8) contusive SCI. Locomotor function was assessed weekly, using the Basso Mouse Scale (BMS), and at the endpoint (six weeks), by footprint analysis. At the endpoint, the volume of preserved white and gray matter, as well as the number of dorsal column axons and perilesional blood vessels rostral to the injury, were quantified. At weeks two and three after SCI, iNOS−/− mice exhibited a significant locomotor improvement compared to WT controls, although a sustained improvement was not observed during later weeks. At the endpoint, iNOS−/− mice showed significantly less preserved white and gray matter, as well as fewer dorsal column axons and perilesional blood vessels, compared to WT controls. While short-term antagonism of iNOS provides histological and functional benefits, its long-term ablation after SCI may be deleterious, blocking protective or reparative processes important for angiogenesis and tissue preservation

Genomic screening of 16 UK native bat species through conservationist networks uncovers coronaviruses with zoonotic potential

There has been limited characterisation of bat-borne coronaviruses in Europe. Here, we screened for coronaviruses in 48 faecal samples from 16 of the 17 bat species breeding in the UK, collected through a bat rehabilitation and conservationist network. We recovered nine complete genomes, including two novel coronavirus species, across six bat species: four alphacoronaviruses, a MERS-related betacoronavirus, and four closely related sarbecoviruses. We demonstrate that at least one of these sarbecoviruses can bind and use the human ACE2 receptor for infecting human cells, albeit suboptimally. Additionally, the spike proteins of these sarbecoviruses possess an R-A-K-Q motif, which lies only one nucleotide mutation away from a furin cleavage site (FCS) that enhances infectivity in other coronaviruses, including SARS-CoV-2. However, mutating this motif to an FCS does not enable spike cleavage. Overall, while UK sarbecoviruses would require further molecular adaptations to infect humans, their zoonotic risk warrants closer surveillance

Crop Updates 2005 - Lupins and Pulses

This session covers sixty five papers from different authors: 1. 2004 LUPIN AND PULSE INDUSTRY HIGHLIGHTS, Peter White Department of Agriculture 2. BACKGROUND, Peter White Department of Agriculture 2004 REGIONAL ROUNDUP 3. Northern Agricultural Region, Martin Harries, Department of Agriculture 4. Central Agricultural Region, Ian Pritchard, Department of Agriculture 5. Great Southern and Lakes, Rodger Beermier, Department of Agriculture 6. Esperance Port Zone, Mark Seymour, Department of Agriculture, and David Syme, The Grain Pool of WA LUPIN AND PULSE PRODUCTION AGRONOMY AND GENETIC IMPROVEMENT 7. Lupin, Martin Harries, Department of Agriculture 8. Narrow-leafed lupin breeding, Bevan Buirchell, Department of Agriculture 9. Yellow lupin breeding in Western Australia, Kedar Adhikari, Mark Sweetingham and Bevan Buirchell, Department of Agriculture 10. WALAB2000 - First Anthracnose resistant albus lupins, Kedar Adhikari, Bevan Buirchell, MarkSweetingham and Geoff Thomas, Department of Agriculture 11. Improving lupin grain quality and yield through genetic manipulation of key physiological traits, Jon Clements1 and Bevan Buirchell2,1CLIMA, The University of Western Australia 2Department of Agriculture 12. Lupin alkaloids in four Australian species, Shao Fang Wang, Chemistry Centre (WA), CLIMA, The University of Western Australia 13. Improving lupin tolerance to herbicides of metribuzin, isoxaflutole and carfentrazone-ethyl, Ping Si1, Mark Sweetingham12, Bevan Buirchell12, David Bowran2 and Huaan Yang12 , 1CLIMA, The University of Western Australia, 2Department of Agriculture 14. Combined cultural and shielded sprayer herbicide application for weed management, Martin Harries and Mike Baker Department of Agriculture 15. Field testing of lupin seed of various sources with and without post maturity, pre harvest rain for field establishment, Martin Harries, Wayne Parker, Mike Baker, Department of Agriculture 16. Lupin seed rate by wide row spacing, Martin Harries, Bob French, Damien Owen D’arcy, Department of Agriculture 17. How environment influences row spacing response in lupins, Bob French, Department of Agriculture 18. The effect of wider row spacing on lupin architecture, growth and nutrient uptake dynamics, Bill Bowden and Craig Scanlan, Department of Agriculture 19. Fertiliser placement and application rate in wide rows, Martin Harries, Damien Owen D’arcy, Department of Agriculture 20. The pros and cons of cowing lupins in ‘wide’ rows, Wayne Parker, Bob French and Martin Harries, Department of Agriculture 21. Investigation into the influence of row orientation in lupin crops, Jeff Russell1 and Angie Roe2, 1Department of Agriculture, 2Farm Focus Consultants 22. Making the most of Mandelup, Greg Shea and Chris Matthews, Department of Agriculture 23. The effect of wild radish density and lupin cultivars on their competition at Merredin, Shahab Pathan, Abul Hashem and Bob French, Department of Agriculture 24. The potential of pearl lupin (Lupinus mutabilis) for southern Australia, Jon Clements1, Mark Sweetingham2, Bevan Buirchell2, Sofia Sipsas2, Geoff Thomas2, John Quealy1, Roger Jones2, Clive Francis1, Colin Smith2 and Gordon Francis1, 1CLIMA, University of Western Australia 2Department of Agriculture 25. Field pea, Mark Seymour, Department of Agriculture 26. Breeding highlights, Tanveer. Khan and Bob French, Department of Agriculture 27. Variety evaluation, Tanveer Khan, Kerry Regan, Jenny Garlinge and Rod Hunter, Department of Agriculture 28. Large scale field pea variety trials, Martin Harries, Department of Agriculture 29. Kaspa demonstrations, Rodger Beermier, Mark Seymour, Ian Pritchard, Graham Mussell, Department of Agriculture 30. Field pea harvesting demonstration at Merredin, Glen Riethmuller, Greg Shea and Bob French, Department of Agriculture 31. Does Kaspa respond differently to disease, fungicides, time of sowing or seed rate, Mark Seymour, Department of Agriculture 32. Field pea response to foliar Manganese in mallee district, Mark Seymour, Department of Agriculture 33. Kaspa harvesting observations 2004, Mark Seymour, Ian Pritchard, Glen Riethmuller, Department of Agriculture 34. ‘Blackspot Manager’ for understanding blackspot of peas and ascochyta blight management, Moin Salam and Jean Galloway, Department of Agriculture 35. 250,000 ha of field pea in WA – Is it sustainable? Larn McMurray1 and Mark Seymour2, 1South Australian Research and Development Institute, 2Department of Agriculture 36. Desi chickpea, Wayne Parker, Department of Agriculture 37. Breeding highlights, Tanveer Khan1,2 and Kadambot Siddique2,1Department of Agriculture, 2CLIMA, The University of Western Australia 38. Variety evaluation, Tanveer Khan, Kerry Regan, Jenny Garlinge and Rod Hunter, Department of Agriculture 39. Large scale variety testing of desi chickpeas, Martin Harries, Greg Shea, Mike Baker, Dirranie Kirby, Department of Agriculture 40. Desi variety chickpea trial, Martin Harries and Murray Blyth, Department of Agriculture 41. Seeding rates and row spacing of chickpea desi, Martin Harries, MurrayBlyth, Damien Owen D’arcy, Department of Agriculture 42. Molecular characterisation of chickpea wild relatives, Fucheng Shan, Heather Clarke and Kadambot Siddique, CLIMA, The University of Western Australia 43. Plant phosphorus status has a limited influence on the concentration of phosphorus-mobilising carboxylates in the rhizosphere of chickpea, Madeleine Wouterlood, Hans Lambers and Erik Veneklaas, The University of Western Australia 44. Kabuli chickpea, Kerry Regan, Department of Agriculture, and CLIMA, The University of Western Australia 45. ‘Kimberly Large’ A high quality and high yielding new variety for the Ord River Irrigation Area, Kerry Regan1,2, Kadambot Siddique2, Peter White1,2, Peter Smith1 and Gae Plunkett1,1Department of Agriculture, 2CLIMA, University of Western Australia 46. Development of ascochyta resistant and high quality varieties for Australia, Kadambot Siddique1, Kerry Regan1,2, Tim Pope1 and Mike Baker2, 1CLIMA, The University of Western Australia 2Department of Agriculture 47. Towards double haploids in chickpeas and field pea, Janine Croser, Julia Wilson and Kadambot Siddique, CLIMA, The University of Western Australia 48. Crossing chickpea with wild Cicer relatives to introduce resistance to disease and tolerance to environmental stress, Heather Clarke and Kadambot Siddique, CLIMA, The University of Western Australia 49. Faba bean, Peter White, Department of Agriculture 50. Germplasm evaluation, Peter White1,2, Kerry Regan1,2, Tim Pope2, Martin Harries1, Mark Seymour1, Rodger Beermier1 and Leanne Young1, 1Department of Agriculture, 2CLIMA, The University of Western Australia 51. Lentil, Kerry Regan, Department of Agriculture, and CLIMA, The University of Western Australia 52. Variety and germplasm evaluation, Kerry Regan1,2, Tim Pope2, Leanne Young1, Martin Harries1, Murray Blyth1 and Michael Materne3, 1Department of Agriculture, 2CLIMA, University of Western Australia, 3Department of Primary Industries, Victoria 53. Lathyrus species, Kadambot Siddique1, Kerry Regan2, and Colin Hanbury2, 1CLIMA, the University of Western Australia, 2Department of Agricultur