Stimulation of c-Kit+ Retinal Progenitor Cells by Stem Cell Factor Confers Protection Against Retinal Degeneration

Background c-Kit/CD117, expressed in a series of tissue-specific progenitor cells, plays an important role in tissue regeneration and tissue homeostasis. We previously demonstrated that organoid-derived c-Kit+ retinal progenitor cells can facilitate the restoration of degenerated retina. Meanwhile, we have identified a population of endogenous c-Kit+ cells in retinas of adult mouse. However, the exact role of these cells in retinal degeneration remains unclear. Methods Retinal degeneration was induced by intravitreal injection of N-methyl-D-aspartate (NMDA). Two days post NMDA challenge, intravitreal injection of stem cell factor (SCF) was performed. Distribution and abundance of c-Kit+ cells and other retinal cells were evaluated by immunochemistry. Retinal function of treated mice was tested via flash electroretinogram (fERG) and the light/dark transition test. Possible regulatory pathways were evaluated by RNA sequencing. Results NMDA challenge increased the total number of c-Kit+ cells in the retinal ganglion cell layer (GCL), while slightly deregulated the protein level of SCF, which is mainly expressed in Müller cells. Both fERG and light/dark transition tests showed that intravitreal injection of SCF effectively improve the visual function of NMDA-treated mice. Consistently, the activation of microglia in injured retina has also been inhibited after SCF treatment. Mechanistically, SCF administration not only prevent the loss of retinal ganglion cells (RGCs), but also maintained the function of RGCs as quantified by fERG. Further, we performed transcriptome sequencing analysis of the retinal cells isolated from SCF-treated mice and the parallel control. Gene Ontology analysis showed that SCF-induced transcriptome changes were closely correlated with eye development-related pathways. Crystallins and several protective factors such as Pitx3 were significantly upregulated by SCF treatment. Conclusions Our results revealed the role of c-Kit+ cells in the protection of RGCs in NMDA-treated mice, via inhibiting the loss of RGCs. Administration of SCF can act as a potent strategy for treating retinal degeneration-related diseases.

Evaluation of the ultradiluted medication MPD 30 CH in the offspring of mice mothers treated with methylphenidate during lactation.

Background: Methylphenidate (MPD) is a non-stimulating amphetamine that has being used for some time in the treatment of Attention Deficit Hyperactivity Disorder (ADHD) and, in adequate doses, it promotes the remission of symptoms and the improvement of important aspects, as social interaction and academic performance1, in patients with ADHD. Literature data indicates that MPD attenuates maternal behavior in mices2. According to this line of study, the work “Repeated methylphenidate administration during lactation reduces maternal behavior, induces maternal tolerance, and increases anxiety-like behavior in pups in adulthood”3 was carried out and confirmed that MPD administration during early lactation disrupts maternal behavior and causes anxiety in pups in adulthood. Would it be possible that ultradiluted and dynamized MPD change pups’ behavior? Objective: The aim of this study was to evaluate how the ultradiluted drug may or may not change the behavior of the animals at issue. Material and Methods: The medication was prepared according to the Brazilian Homeopathic Pharmacopeia, in the 30 CH dilution. The present study was approved by the Ethics Committee for Animal Experimentation of the Paulista University (No. 256/14 CEP / ICS / UNIP). Animals in this study were the same of the study above mentioned, and already published. Adult male mice were grouped among 13 animals of the experimental group (adults, offspring of mothers that received MPD during pregnancy) and 9 animals from the mother-control group, which did not take MPD during pregnancy. The 22 animals took ultradiluted MPD 30 CH medication in their drinking water ad libitum, for 20 days. In each water drinker, 5 drops of medication were added and stirred. Behavioral tests, such as the Open Field and the Light Dark Transition Test for mice, were performed. Data was analyzed statistically by the Student's T-Test to compare parametric data from two groups and the Mann-Whitney Test for nonparametric data, where p ≤ 0.05 is considered significant. Results and Discussion: In the Open Field Test, from the group of mothers medicated with methylphenidate during pregnancy, before the medication MPD 30 CH, animals showed a lower mobility and a greater immobility (p≤ 0.05) compared to the control-animals; after medication with the MPD 30 CH, animals exhibited an increase in mobility and a decrease in immobility, leading to no statistical difference between the medication group and the control group. In the Light Dark Transition Test for mice, experimental animals spent more time in the dark box and exhibited a decrease of the Rearing, presenting an anxious behavior; after the MPD medication, there were no more differences between experimental and control groups. Indiscriminate use of amphetamines has increased in recent years and this use, when not monitored, can cause serious adverse effects4. In this sense, ultradiluted medication can collaborate with the remission of possible undesirable effects. Conclusion: Initially, the MPD 30 CH changed the behavior shown by animals born from mothers that took methylphenidate during lactation and presented an anxious behavior as an unexpected effect. The mice that took the MPD 30 CH did not present the anxious behavior. Other experiments should be conducted to confirm the results of this study.

Ozone uptake at night is more damaging to plants than equivalent day-time flux

Main conclusion Plants exposed to equivalent ozone fluxes administered during day-time versus night-time exhibited greater losses in biomass at night and this finding is attributed to night-time depletion of cell wall-localised ascorbate. Abstract The present study employed Lactuca sativa and its closest wild relative, L. serriola, to explore the relative sensitivity of plants to ozone-induced oxidative stress during day-time versus night-time. By controlling atmospheric ozone concentration and measuring stomatal conductance, equivalent ozone uptake into leaves was engineered during day and night, and consequences on productivity and net CO2 assimilation rate were determined. Biomass losses attributable to ozone were significantly greater when an equivalent dose of ozone was taken-up by foliage at night compared to the day. Linkages between ozone impacts and ascorbic acid (AA) content, redox status and cellular compartmentation were probed in both species. Leaf AA pools were depleted by exposure of plants to darkness, and then AA levels in the apoplast and symplast were monitored on subsequent transfer of plants to the light. Apoplast AA appeared to be more affected by light–dark transition than the symplast pool. Moreover, equivalent ozone fluxes administered to leaves with contrasting AA levels resulted in contrasting effects on the light-saturated rate of CO2 assimilation (Asat) in both species. Once apoplast AA content recovered to pre-treatment levels, the same ozone flux resulted in no impacts on Asat. The results of the present investigation reveal that plants are significantly more sensitive to equivalent ozone fluxes taken-up at night compared with those during the day and were consistent with diel shifts in apoplast AA content and/or redox status. Furthermore, findings suggest that some thought should be given to weighing regional models of ozone impacts for extraordinary night-time ozone impacts.

Acute Stress Induced Behavioral Deficits In Rats: Relationship With Oxidative Stress, Leptin And HPA Axis

Acute exposure to stress is connected to many disorders that promote the toxicity of oxygen radical generators leading to increase in the levels of enzymes and also the activation of the HPA axis. The present study uses a preclinical approach to elucidate some prospective stress-induced behavioral and biochemical effects. The aim of current study was to investigate the relationship between stress and behavioral changes after exposing animals to 2h immobilization stress. We also evaluated the concentration of corticosterone, glucose and endogenous leptin levels in unstressed and stressed animals to explore the possible role of HPA axis in the modulation of stressed induced behavioral deficits. Rats were divided into stressed and unstressed groups. Behavioral activities were monitored in open field activity and light dark transition box after the termination of 2h immobilization period. Animals were then decapitated and plasma samples were collected for catalase, SOD, corticosterone, and glucose estimation. Results showed that exposure to acute stress produced a significant decrease in the activity of rats in the novel environment (open field) and light dark transition box. On the other hand, concomitant elevated level of peripheral markers of oxidative stress such as oxidative enzymes, corticosterone and endogenous leptin were also observed. Therefore, current study seems to suggest an important role of compounds having antioxidant properties for the treatment of stress and related disorders.

Subtle Impact of Akt1 and Akt3 on Exploratory Behavior in Gene Targeted Mice

The present study explored the impact of Akt1 and Akt3 on behavior. Akt1 (akt1-/-) and Akt3 (akt3-/-) knockout mice were compared to wild type (wt) mice. The akt1-/- mice, akt3-/- mice, and wt mice were similar in most parameters of the open-field test. However, the distance traveled in the center area was slightly but significantly less in akt3-/- mice than in wt mice. In the light/dark transition test akt1-/- mice had significantly lower values than wt mice and akt3-/- mice for distance traveled, number of rearings, rearing time in the light area, as well as time spent and distance traveled in the entrance area. They were significantly different from akt3-/- mice in the distance traveled, visits, number of rearings, rearing time in the light area, as well as time spent, distance traveled, number of rearings, and rearing time in the entrance area. In the O-maze the time spent, and the visits to open arms, as well as the number of protected and unprotected headdips were significantly less in akt1-/- mice than in wt mice, whereas the time spent in closed arms was significantly more in akt1-/- mice than in wt mice. Protected and unprotected headdips were significantly less in akt3-/- mice than in wt mice. In closed area, akt3-/- mice traveled a significantly larger distance at larger average speed than akt1-/- mice. No differences were observed between akt1-/- mice, akt3-/- mice and wt-type mice in the time of floating during the forced swimming test. In conclusion, akt1-/- mice and less so akt3-/ mice display subtle changes in behavior.