Transcriptional up-regulation of the protooncogenes c-fos and c-jun following vitreous removal and short-term in vitro culture of bovine lenses

Glutamate receptors and signal transduction in learning and memory

The plasticity of the central nervous system helps form the basis for the neurobiology of learning and memory. Long-term potentiation (LTP) is the main form of synaptic plasticity, reflecting the activity level of the synaptic information storage process, and provides a good model to study the underlying mechanisms of learning and memory. The glutamate receptor-mediated signal pathway plays a key role in the induction and maintenance of LTP, and hence the regulation of learning and memory. The progress in the understanding of the glutamate receptors and related signal transduction systems in learning and memory research are reviewed in this article.

Mercury pollution in two typical areas in Guizhou province, China and its neurotoxic effects in the brains of rats fed with local polluted rice

Guizhou province, which located in southwestern of China, is an important mercury (Hg) production center. This study was to investigate the environmental levels and ecological effects of mercury in two typical Hg polluted areas in Guizhou province. In addition, to improve the understanding of the neurotoxic effects of Hg, a rats based laboratory study was also carried out in this study. Samples of water, soil, plants, crops and animals collected from Wanshan mercury mine area, Guzhou province, were analyzed by mercury analyzer. The effects of Hg contaminated rice on the expression of c-jun mRNA in rat's brain and the expression of c-JUN protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed that the mercury contents in most environmental samples of aquatics, soil, atmosphere and the biomass of corn, plant and animals, were higher than the national standard and the corresponding data from unpolluted area. It was found mercury pollutions were significant in soil and air. In the laboratory study, the expression of c-jun mRNA and its protein was significantly induced by Hg polluted rice collected from local area. Selenium could reduce the Hg accumulation in the body and had antagonist effect on Hg in terms of the expression of c-jun mRNA and c-JUN protein. The environmental data and Hg levels in different creatures collected in this study will facilitate the environmental and ecological risk assessment of Hg in the polluted areas. It was urged to be alert of mental health problem in human beings when any kind of Hg-polluted food was taken. More efforts should be performed to protect the local ecosystem and human health in the mercury polluted area of Wanshan, Guizhou province of China.

Transcriptional activation in lens epithelial cells following an ocular blunt trauma

PURPOSE

To determine whether an ocular blunt trauma activates anterior ocular segment (cornea and lens) by examining the expression patterns of c-fos and c-jun mRNAs in these tissues of an eye of adult rat following a blunt trauma.

SETTING

Department of Ophthalmology, Wakayama Medical University School of Medicine, Kimiidera, Wakayama, Japan.

METHODS

Adult Wistar rats (n=36) were generally anesthetized by ether inhalation. One eye was hit with an iron sphere (30 gram) that fell to the eye from 1 m. After the procedure, the animals were killed and the affected eye was enucleated at 15, 30, 60, 120, and 180 minutes. In situ hybridization using radiolabeled oligoprobes was used to detect mRNAs of c-fos and c-jun in tissue.

RESULTS

The c-fos and c-jun mRNAs were not detected in the epithelium of uninjured cornea and lens by in situ hybridization. The mRNAs for c-fos and c-jun were then detected in corneal epithelium from 15 to 60 minutes posttreatment, and were no longer observed thereafter. In lens epithelium, mRNA for c-fos or c-jun were transiently detected from 15 to 60 minutes or 30 minutes posttreatment, respectively.

CONCLUSION

The c-fos and c-jun mRNAs were transiently expressed in corneal and lens epithelial cells after blunt trauma. Ocular blunt trauma activates corneal and lens epithelial cells without apparent corneal ablation or direct injury in the lens epithelium. Such activation in lens epithelium might be involved in cataractogenesis.

Transcription activation in lens epithelial cells after anterior capsule rubbing in rats. expression of c-Fos

PURPOSE

To determine whether lens epithelial cells (LECs) are transcriptionally activated after a foreign body is attached to the anterior lens surface.

SETTING

Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan.

METHODS

One eye of adult Wistar rats (N = 32) was used. After the anterior capsule of the lens was rubbed with a dull 27-gauge needle 10 times, the eye was enucleated immediately (within 1 minute) or at 30 minutes or 1, 3, or 5 hours. The 32 globes were immunohistochemically analyzed using anti-c-Fos and anti-c-Jun antibodies.

RESULTS

Immunohistochemistry showed that normal LECs lacked immunoreactivity for c-Fos or c-Jun. The c-Fos protein was localized in the nuclei of LECs in the equatorial region of the injured lens 3 hours after treatment and was not detected thereafter. The c-Jun protein was not detected at any interval.

CONCLUSION

The protein c-Fos was transiently expressed in equatorial LECs after the anterior lens capsule was rubbed, indicating that equatorial LECs are transcriptionally activated by minor mechanical stimuli to the anterior lens surface.

Expression of transcription factor AP-1 in rat lens epithelial cells during wound repair

We examined the spatial and temporal expression patterns of proteins and mRNAs of the components of transcription factor activator protein 1 (AP-1) to examine the activation pattern of lens epithelial cells during lens wound repair following an anterior capsular injury. One eye of adult Wistar rats (n = 106) were used. After making a lens anterior capsule incision with a hypodermic needle, the affected eye was enucleated 0 and 30 min, 1, 3, 5, 8, 10, 15, 20, 24 hr after injury. Forty six globes were processed for in situ hybridization with oligonucleotide probes for c-fos, fosB, c-jun, junB and junD mRNAs, and 60 globes were immunohistochemically analysed using anti-c-Fos and anti-c-Jun antibodies. Normal lens epithelial cells expressed mRNA signals for junD, but not for c-fos, fosB, c-jun, and junB. mRNAs for c-fos, fosB, c-jun, and junB were detected in the whole lens epithelium from the vicinity to the wound to the equator from 30 min to 8 hr post-injury with their peaks after 30 min to 1 hr, but were no longer detected at 10 hr or later. Expression of c-fos mRNA in the equatorial lens cells was more marked than that of c-jun mRNA. Immunohistochemistry showed that c-Fos protein was expressed in the lens epithelial cells in both the anterior and equatorial regions of the injured lens from 1 to 10 hr after injury, and was no longer detected at 12 hr. C-Jun protein was detected only in the equatorial lens cells from 1 to 5 hr after injury, and was no longer detected at 8 hr. Lens epithelial cells except those in the equatorial region did not express c-Jun protein. These findings indicate that transcriptional activation of lens epithelial cells is initiated in the very early phase after the lens injury, i.e. 30 min post-injury, suggesting that AP-1 may play important roles in regulating lens cell behavior during lens wound repair in rats.