• Molecules and Cells
• /
• 제38권8호
• /
• pp.729-733
• /
• 2015

C. elegans has two functional peroxidasins (PXN), PXN-1 and PXN-2. PXN-2 is essential to consolidate the extracellular matrix during development and is suggested to interact with PXN-1 antagonistically. pxn-1 is involved in neuronal development and possibly maintenance; therefore, we investigated the relationship between pxn-1 and pxn-2 in neuronal development and in aging. During neuronal development, defects caused by pxn-1 overexpression were suppressed by overexpression of both pxn-1 and pxn-2. In neuronal aging process, pxn-1 mutants showed less age-related neuronal defects, such as neuronal outgrowth, neuronal wavy processes, and enhanced short-term memory performance. In addition, pxn-2 overexpressing animals retained an intact neuronal morphology when compared with age-matched controls. Consistent with these results, overexpression of both pxn-1 and pxn-2 restored the severe neuronal defects present with pxn-1 overexpression. These results implied that there is a negative relationship between pxn-1 and pxn-2 via pxn-1 regulating pxn-2. Therefore, pxn-1 may function in neuronal development and age-related neuronal maintenance through pxn-2.

• Molecules and Cells
• /
• 제39권9호
• /
• pp.680-686
• /
• 2016

Uncoupling proteins (UCPs) are mitochondrial inner membrane proteins that function to dissipate proton motive force and mitochondrial membrane potential. One UCP has been identified in Caenorhabditis elegans (C. elegans), namely UCP-4. In this study, we examined its expression and localization using a GFP marker in C. elegans. ucp-4 was expressed throughout the body from early embryo to aged adult and UCP-4 was localized in the mitochondria. It is known that increased mitochondrial membrane protential leads to a reactive oxygen species (ROS) increase, which is associated with age-related diseases, including neurodegenerative diseases in humans. A ucp-4 mutant showed increased mitochondrial membrane protential in association with increased neuronal defects during aging, and the neurons of ucp-4 overexpressing animals showed decreased neuronal defects during aging. These results suggest that UCP-4 may be involved in neuroprotection during aging via relieving mitochondrial membrane protential. We also investigated the relationship between UCP-4 and innate immunity because increased ROS can affect innate immunity. ucp-4 mutant displayed increased resistance to the pathogen Staphylococcus aureus compared to wild type. The enhanced immunity in the ucp-4 mutant could be related to increased mitochondrial membrane protential, presumably followed by increased ROS. In summary, UCP-4 might have an important role in neuronal aging and innate immune responses through mediating mitochondrial membrane protential.

• BMB Reports
• /
• 제42권1호
• /
• pp.6-15
• /
• 2009

The most common genetic disorder Down syndrome (DS) displays various developmental defects including mental retardation, learning and memory deficit, the early onset of Alzheimer's disease (AD), congenital heart disease, and craniofacial abnormalities. Those characteristics result from the extra-genes located in the specific region called 'Down syndrome critical region (DSCR)' in human chromosome 21. In this review, we summarized the recent findings of the DYRK1A and RCAN1 genes, which are located on DSCR and thought to be closely associated with the typical features of DS patients, and their implication to the pathogenesis of neural defects in DS. DYRK1A phosphorylates several transcriptional factors, such as CREB and NFAT, endocytic complex proteins, and AD-linked gene products. Meanwhile, RCAN1 is an endogenous inhibitor of calcineurin A, and its unbalanced activity is thought to cause major neuronal and/or non-neuronal malfunction in DS and AD. Interestingly, they both contribute to the learning and memory deficit, altered synaptic plasticity, impaired cell cycle regulation, and AD-like neuropathology in DS. By understanding their biochemical, functional and physiological roles, we hope to get important molecular basis of DS pathology, which would consequently lead to the basis to develop the possible therapeutic tools for the neural defects in DS.

• Molecules and Cells
• /
• 제40권11호
• /
• pp.864-870
• /
• 2017

The uncoupling protein 4 (ucp-4) gene is involved in age-dependent neurodegeneration in C. elegans. Therefore, we aimed to investigate the mechanism underlying the association between mitochondrial uncoupling and neurodegeneration by examining the effects of uncoupling agents and ucp-4 overexpression in C. elegans. Treatment with either DNP or CCCP improved neuronal defects in wild type during aging. Uncoupling agents also restored neuronal phenotypes of ucp-4 mutants to those exhibited by wild type, while ucp-4 overexpression attenuated the severity of age-dependent neurodegeneration. Neuronal improvements were further associated with reductions in mitochondrial membrane potentials. However, these age-dependent neuroprotective effects were limited in mitophagy-deficient mutant, pink-1, background. These results suggest that membrane uncoupling can attenuate age-dependent neurodegeneration by stimulating mitophagy.

• Archives of Plastic Surgery
• /
• 제33권2호
• /
• pp.205-212
• /
• 2006

Using adipose derived stem cells(ASCs), neurogenic differentiation was induced in a mono layered culture medium containing neuronal induction agents. Cells differentiated to the neuronal cells were observed with a inverted microscope and immunofluorecent study. We made a 15 mm long defect in the sciatic nerve of 14 rats and connected a silicone tube to the defect. Then, we mixed neuronal progenitor cells differentiated from ASCs with collagen gel and grafted them to a group of rats(experimental group) and grafted only collagen gel into another group(control group). In 4 and 8 weeks after the graft, histological observation was made. According to the result, the number and diameter of myelinated axons were significantly increased in the experimental group. In addition, the nerve conduction velocity was improved more in the experimental group and neovascularity also increased. Moreover, reaction with S100 and p75 was observed in regenerated nerves in the experimental group, suggesting that the grafted cells were differentiated into supportive cells such as Schwann's cells. In conclusion, this research proved that ASCs can multiply and differentiate into neuronal cells. If they are grafted into nerve defects, the grafted cells are differ entiated into supportive cells such as Schwann's cells and thus contribute to nerve regeneration. Accordingly, the use of adipose tissue obtained easily without the limitation of donor site can be greatly helpful in treating peripheral nerve defects.

• Molecules and Cells
• /
• 제45권8호
• /
• pp.588-602
• /
• 2022

Various RNA-binding proteins (RBPs) are key components in RNA metabolism and contribute to several neurodevelopmental disorders. To date, only a few of such RBPs have been characterized for their roles in neocortex development. Here, we show that the RBP, Rbms1, is required for radial migration, polarization and differentiation of neuronal progenitors to neurons in the neocortex development. Rbms1 expression is highest in the early development in the developing cortex, with its expression gradually diminishing from embryonic day 13.5 (E13.5) to postnatal day 0 (P0). From in utero electroporation (IUE) experiments when Rbms1 levels are knocked down in neuronal progenitors, their transition from multipolar to bipolar state is delayed and this is accompanied by a delay in radial migration of these cells. Reduced Rbms1 levels in vivo also reduces differentiation as evidenced by a decrease in levels of several differentiation markers, meanwhile having no significant effects on proliferation and cell cycle rates of these cells. As an RNA binding protein, we profiled the RNA binders of Rbms1 by a cross-linked-RIP sequencing assay, followed by quantitative real-time polymerase chain reaction verification and showed that Rbms1 binds and stabilizes the mRNA for Efr3a, a signaling adapter protein. We also demonstrate that ectopic Efr3a can recover the cells from the migration defects due to loss of Rbms1, both in vivo and in vitro migration assays with cultured cells. These imply that one of the functions of Rbms1 involves the stabilization of Efr3a RNA message, required for migration and maturation of neuronal progenitors in radial migration in the developing neocortex.

• BMB Reports
• /
• 제53권1호
• /
• pp.35-46
• /
• 2020

Despite enduring diverse insults, mitochondria maintain normal functions through mitochondrial quality control. However, the failure of mitochondrial quality control resulting from excess damage and mechanical defects causes mitochondrial dysfunction, leading to various human diseases. Recent studies have reported that mitochondrial defects are found in Alzheimer's disease (AD) and worsen AD symptoms. In AD pathogenesis, mitochondrial dysfunction-driven generation of reactive oxygen species (ROS) and their contribution to neuronal damage has been widely studied. In contrast, studies on mitochondrial dysfunction-associated inflammatory responses have been relatively scarce. Moreover, ROS produced upon failure of mitochondrial quality control may be linked to the inflammatory response and influence the progression of AD. Thus, this review will focus on inflammatory pathways that are associated with and initiated through defective mitochondria and will summarize recent progress on the role of mitochondria-mediated inflammation in AD. We will also discuss how reducing mitochondrial dysfunction-mediated inflammation could affect AD.

• Journal of Genetic Medicine
• /
• 제1권1호
• /
• pp.33-37
• /
• 1997

Spinal muscular atrophy (SMA) is the second most common fatal disease of childhood with autosomal dominant mode of inheritance, and in its less severe form the third most common neuromuscular disease of childhood after Duchenne muscular dystrophy. The genetic defect was found to be on the long arm of chromosome 5 (5q11.2-q13.3) where many genes and microsatellite markers were missing. One of the most important genes is the Survival Motor Neuron (SMN) gene which is homozygously missing in 90% of SMA patients. Another important gene, the Neuronal Apoptosis Inhibitory Protein (NAIP) gene was found to be defective in 67% of SMA type I patients. Studies so far suggest SMA occurs when the genes on the long arm of chromosome 5 are mutated or deleted. Recently our hospital encountered 2 SMA patients of type I and II respectively. These patients both had homozygously defective SMN genes but intact NAIP genes. We are reporting these cases with bibliographic review and discussion. Korean SMA patients presumably have defects in SMN genes similar to those found in European patients, although the significance of NAIP genes remains to be established. SMN gene defects can be easily diagnosed using PCR and restriction enzymes, and this method could be applied towards convenient prenatal diagnosis and towards screening for family members at risk.

• Molecules and Cells
• /
• 제38권1호
• /
• pp.51-57
• /
• 2015

The Caenorhabditis elegans peroxidasins, PXN-1 and PXN-2, are extracellular peroxidases; pxn-2 is involved in muscle-epidermal attachment during embryonic morphogenesis and in specific axon guidance. Here we investigate potential roles of the other homologue of peroxidasin, pxn-1, in C. elegans. A pxn-1 deletion mutant showed high lethality under heat-stress conditions. Using a transcriptional GFP reporter, pxn-1 expression was observed in various tissues including neurons, muscles, and hypodermis. A translational fusion showed that PXN-1::GFP was secreted and localized in extracellular matrix, particularly along body wall muscles and pharyngeal muscles. Various neuronal developmental defects were observed in pxn-1 mutants and in pxn-1 over-expressing animals, including handedness, branching, breakage, tangling, and defasciculation. These results suggest that pxn-1, like other peroxidasins, plays an important role throughout development.

• The Korean Journal of Physiology and Pharmacology
• /
• 제16권2호
• /
• pp.79-89
• /
• 2012

We examine whether Phellodendron amurense (PA) and its major alkaloid compound, berberine (BER), improved memory defects caused by administering scopolamine in rats. Effects of PA and BER on the acetylcholinergic system and pro-inflammatory cytokines in the hippocampus were also investigated. Male rats were administered daily doses for 14 days of PA (100 and 200 mg/kg, i.p.) and BER (20 mg/kg, i.p.) 30 min before scopolamine injection (2 mg/kg, i.p.). Daily administration of PA and BER improved memory impairment as measured by the passive avoidance test and reduced the escape latency for finding the platform in the Morris water maze test. Administration of PA and BER significantly alleviated memory-associated decreases in cholinergic immunoreactivity and restored brain-derived neurotrophic factor and cAMP-response element-binding protein mRNA expression in the hippocampus. PA and BER also decreased significantly the expression of proinflammatory cytokines such as interleukin-$1{\beta}$, tumor necrosis factor-${\alpha}$ and cyclooxygenase-2 mRNA in the hippocampus. These results demonstrated that PA and BER had significant neuroprotective effects against neuronal impairment and memory dysfunction caused by scopolamine in rats. These results suggest that PA and BER may be useful as therapeutic agents for improving cognitive functioning by stimulating cholinergic enzyme activity and alleviating inflammatory responses.