Enhanced Motor Function by Training in Spinal Cord Contused Rats Following Radiation Therapy

Weight-bearing stepping, without supraspinal re-connectivity, can be attained by treadmill training in an animal whose spinal cord has been completely transected at the lower thoracic level. Repair of damaged tissue and of supraspinal connectivity/circuitry following spinal cord injury in rat can be achieved by specific cell elimination with radiation therapy of the lesion site delivered within a critical time window, 2-3 weeks postinjury. Here we examined the effects of training in the repaired spinal cord following clinical radiation therapy. Studies were performed in a severe rat spinal cord contusion injury model, one similar to fracture/crush injuries in humans; the injury was at the lower thoracic level and the training was a combined hindlimb standing and stepping protocol. Radiotherapy, in a similar manner to that reported previously, resulted in a significant level of tissue repair/preservation at the lesion site. Training in the irradiated group, as determined by limb kinematics tests, resulted in functional improvements that were significant for standing and stepping capacity, and yielded a significant direct correlation between standing and stepping performance. In contrast, the training in the unirradiated group resulted in no apparent beneficial effects, and yielded an inverse correlation between standing and stepping performance, e.g., subject with good standing showed poor stepping capacity. Further, without any training, a differential functional change was observed in the irradiated group; standing capacity was significantly inhibited while stepping showed a slight trend of improvement compared with the unirradiated group. These data suggest that following repair by radiation therapy the spinal circuitries which control posture and locomotor were modified, and that the beneficial functional modulation of these circuitries is use dependent. Further, for restoring beneficial motor function following radiotherapy, training seems to be crucial

Impact of the RTS,S Malaria Vaccine Candidate on Naturally Acquired Antibody Responses to Multiple Asexual Blood Stage Antigens

Partial protective efficacy lasting up to 43 months after vaccination with the RTS,S malaria vaccine has been reported in one cohort (C1) of a Phase IIb trial in Mozambique, but waning efficacy was observed in a smaller contemporaneous cohort (C2). We hypothesized that low dose exposure to asexual stage parasites resulting from partial pre-erythrocytic protection afforded by RTS,S may contribute to long-term vaccine efficacy to clinical disease, which was not observed in C2 due to intense active detection of infection and treatment. in C2 only (Hazard Ratio [HR]: 0.76, 95% CI 0.66–0.88; HR: 0.75, 95% CI 0.62–0.92, respectively).Vaccination with RTS,S modestly reduces anti-AMA-1 and anti-MSP-1 antibodies in very young children. However, for antigens associated with lower risk of clinical malaria, there were no vaccine group or cohort-specific effects, and age did not influence antibody levels between treatment groups for these antigens. The antigens tested do not explain the difference in protective efficacy in C1 and C2. Other less-characterized antigens or VSA may be important to protection

A Role for Immune Responses against Non-CS Components in the Cross-Species Protection Induced by Immunization with Irradiated Malaria Sporozoites

Immunization with irradiated Plasmodium sporozoites induces sterile immunity in rodents, monkeys and humans. The major surface component of the sporozoite the circumsporozoite protein (CS) long considered as the antigen predominantly responsible for this immunity, thus remains the leading candidate antigen for vaccines targeting the parasite's pre-erythrocytic (PE) stages. However, this role for CS was questioned when we recently showed that immunization with irradiated sporozoites (IrrSpz) of a P. berghei line whose endogenous CS was replaced by that of P. falciparum still conferred sterile protection against challenge with wild type P. berghei sporozoites. In order to investigate the involvement of CS in the cross-species protection recently observed between the two rodent parasites P. berghei and P. yoelii, we adopted our gene replacement approach for the P. yoelii CS and exploited the ability to conduct reciprocal challenges. Overall, we found that immunization led to sterile immunity irrespective of the origin of the CS in the immunizing or challenge sporozoites. However, for some combinations, immune responses to CS contributed to the acquisition of protective immunity and were dependent on the immunizing IrrSpz dose. Nonetheless, when data from all the cross-species immunization/challenges were considered, the immune responses directed against non-CS parasite antigens shared by the two parasite species played a major role in the sterile protection induced by immunization with IrrSpz. This opens the perspective to develop a single vaccine formulation that could protect against multiple parasite species

Nutrients cause grassland biomass to outpace herbivory

Human activities are transforming grassland biomass via changing climate, elemental nutrients, and herbivory. Theory predicts that food-limited herbivores will consume any additional biomass stimulated by nutrient inputs ('consumer-controlled'). Alternatively, nutrient supply is predicted to increase biomass where herbivores alter community composition or are limited by factors other than food ('resource-controlled'). Using an experiment replicated in 58 grasslands spanning six continents, we show that nutrient addition and vertebrate herbivore exclusion each caused sustained increases in aboveground live biomass over a decade, but consumer control was weak. However, at sites with high vertebrate grazing intensity or domestic livestock, herbivores consumed the additional fertilization-induced biomass, supporting the consumer-controlled prediction. Herbivores most effectively reduced the additional live biomass at sites with low precipitation or high ambient soil nitrogen. Overall, these experimental results suggest that grassland biomass will outstrip wild herbivore control as human activities increase elemental nutrient supply, with widespread consequences for grazing and fire risk

Perineuronal Nets Play a Role in Regulating Striatal Function in the Mouse

The striatum is the primary input nucleus of the basal ganglia, a collection of nuclei that play important roles in motor control and associative learning. We have previously reported that perineuronal nets (PNNs), aggregations of chondroitin-sulfate proteoglycans (CSPGs), form in the matrix compartment of the mouse striatum during the second postnatal week. This period overlaps with important developmental changes, including the attainment of an adult-like gait. Here, we investigate the identity of the cells encapsulated by PNNs, characterize their topographical distribution and determine their function by assessing the impact of enzymatic digestion of PNNs on two striatum-dependent behaviors: ambulation and goal-directed spatial learning. We show PNNs are more numerous caudally, and that a substantial fraction (41%) of these structures surrounds parvalbumin positive (PV+) interneurons, while approximately 51% of PV+ cells are ensheathed by PNNs. The colocalization of these structures is greatest in dorsal, lateral and caudal regions of the striatum. Bilateral digestion of striatal PNNs led to an increase in both the width and variability of hind limb gait. Intriguingly, this also resulted in an improvement in the acquisition rate of the Morris water maze. Together, these data show that PNNs are associated with specific elements of striatal circuits and play a key role in regulating the function of this important structure in the mouse

Dipolar cortico-muscular electrical stimulation: a novel method that enhances motor function in both - normal and spinal cord injured mice

<p>Abstract</p> <p>Background</p> <p>Electrical stimulation of the central and peripheral nervous systems is a common tool that is used to improve functional recovery after neuronal injury.</p> <p>Methods</p> <p>Here we described a new configuration of electrical stimulation as it was tested in anesthetized control and spinal cord injury (SCI) mice. Constant voltage output was delivered through two electrodes. While the negative voltage output (ranging from -1.8 to -2.6 V) was delivered to the muscle via transverse wire electrodes (diameter, 500 μm) located at opposite ends of the muscle, the positive output (ranging from + 2.4 to +3.2 V) was delivered to the primary motor cortex (M1) (electrode tip, 100 μm). The configuration was named dipolar cortico-muscular stimulation (dCMS) and consisted of 100 pulses (1 ms pulse duration, 1 Hz frequency).</p> <p>Results</p> <p>In SCI animals, after dCMS, cortically-elicited muscle contraction improved markedly at the contralateral (456%) and ipsilateral (457%) gastrocnemius muscles. The improvement persisted for the duration of the experiment (60 min). The enhancement of cortically-elicited muscle contraction was accompanied by the reduction of M1 maximal threshold and the potentiation of spinal motoneuronal evoked responses at the contralateral (313%) and ipsilateral (292%) sides of the spinal cord. Moreover, spontaneous activity recorded from single spinal motoneurons was substantially increased contralaterally (121%) and ipsilaterally (54%). Interestingly, spinal motoneuronal responses and muscle twitches evoked by the test stimulation of non-treated M1 (received no dCMS) were significantly enhanced as well. Similar results obtained from normal animals albeit the changes were relatively smaller.</p> <p>Conclusion</p> <p>These findings demonstrated that dCMS could improve functionality of corticomotoneuronal pathway and thus it may have therapeutic potential.</p

Tanshinone IIA Attenuates the Inflammatory Response and Apoptosis after Traumatic Injury of the Spinal Cord in Adult Rats

BACKGROUND: Spinal cord injury (SCI), including immediate mechanical injury and secondary injury, is associated with the inflammatory response, apoptosis and oxidative stress in response to traumatic injury. Tanshinone IIA (TIIA) is one of the major extracts obtained from Salvia miltiorrhiza BUNGE, which has anti-inflammatory and anti-apoptotic effects on many diseases. However, little is known about the effects of TIIA treatment on SCI. Therefore, the aim of the present study is to evaluate the pharmacological action of TIIA on secondary damage and the underlying mechanisms of experimental SCI in rats. METHODOLOGY/PRINCIPAL FINDINGS: SCI was generated using a weight drop device on the dorsal spinal cord via a two-level T9-T11 laminectomy. SCI in rats resulted in severe trauma, characterized by locomotor disturbance, edema, neutrophil infiltration, the production of astrocytes and inflammatory mediators, apoptosis and oxidative stress. TIIA treatment (20 mg/kg, i.p.) after SCI induced significant effects: (1) improved motor function (Basso, Beattie and Bresnahan scores), (2) reduced the degree of tissue injury (histological score), neutrophil infiltration (myeloperoxidase activity) and the expression of astrocytes, (3) inhibited the activation of SCI-related pathways, such as NF-κB and MAPK signaling pathways, (4) decreased the production of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and iNOS, (5) reduced apoptosis (TUNEL staining, and Bcl-2 and caspase-3 expression) and (6) reversed the redox state imbalance. CONCLUSIONS/SIGNIFICANCE: The results clearly show that TIIA has a prominent protective effect against SCI through inhibiting the inflammatory response and apoptosis in the spinal cord tissue after SCI

The Puf-Family RNA-Binding Protein Puf2 Controls Sporozoite Conversion to Liver Stages in the Malaria Parasite

Malaria is a vector-borne infectious disease caused by unicellular, obligate intracellular parasites of the genus Plasmodium. During host switch the malaria parasite employs specialized latent stages that colonize the new host environment. Previous work has established that gametocytes, sexually differentiated stages that are taken up by the mosquito vector, control expression of genes required for mosquito colonization by translational repression. Sexual parasite development is controlled by a DEAD-box RNA helicase of the DDX6 family, termed DOZI. Latency of sporozoites, the transmission stage injected during an infectious blood meal, is controlled by the eIF2alpha kinase IK2, a general inhibitor of protein synthesis. Whether RNA-binding proteins participate in translational regulation in sporozoites remains to be studied. Here, we investigated the roles of two RNA-binding proteins of the Puf-family, Plasmodium Puf1 and Puf2, during sporozoite stage conversion. Our data reveal that, in the rodent malaria parasite P. berghei, Puf2 participates in the regulation of IK2 and inhibits premature sporozoite transformation. Inside mosquito salivary glands puf2(-) sporozoites transform over time to round forms resembling early intra-hepatic stages. As a result, mutant parasites display strong defects in initiating a malaria infection. In contrast, Puf1 is dispensable in vivo throughout the entire Plasmodium life cycle. Our findings support the notion of a central role for Puf2 in parasite latency during switch between the insect and mammalian hosts

Delineation of Stage Specific Expression of Plasmodium falciparum EBA-175 by Biologically Functional Region II Monoclonal Antibodies

EBA-175 binds its receptor sialic acids on glycophorin A when invading erythrocytes. The receptor-binding region (RII) contains two cysteine-rich domains with similar cysteine motifs (F1 and F2). Functional relationships between F1 and F2 domains and characterization of EBA-175 were studied using specific monoclonal antibodies (mAbs) against these domains..The role of the F1 and F2 domains in erythrocyte invasion and binding was elucidated with mAbs. These mAbs interfere with native EBA-175 binding to erythrocyte in a synergistic fashion. The stage specific expression of EBA-175 showed that the primary focus of activity was the merozoite stage. A recombinant RII protein vaccine consisting of both F1 and F2 domains that could induce synergistic activity should be optimal for induction of antibody responses that interfere with merozoite invasion of erythrocytes