Retroviral Expression of Arginine Decarboxylase Attenuates Oxidative Burden in Mouse Cortical Neural Stem Cells

Bokara, Kiran Kumar,Kwon, Ki Hyo,Nho, Yoonmi,Lee, Won Taek,Park, Kyung Ah,Lee, Jong Eun Mary Ann Liebert 2011 STEM CELLS AND DEVELOPMENT Vol.20 No.3

Biocompatability of carbon nanotubes with stem cells to treat CNS injuries

Kiran Kumar Bokara,Jong Youl Kim,Young Il Lee,Kyungeun Yun,Tom J Webster,Jong Eun Lee 대한해부학회 2013 Anatomy & Cell Biology Vol.46 No.2

Cases reporting traumatic injuries to the brain and spinal cord are extended range of disorders that affect a large percentage of the world's population. But, there are only few effective treatments available for central nervous system (CNS) injuries because the CNS is refractory to axonal regeneration and relatively inaccessible to many pharmacological treatments. The use of stem cell therapy in regenerative medicine has been extensively examined to replace lost cells during CNS injuries. But, given the complexity of CNS injuries oxidative stress, toxic byproducts, which prevails in the microenvironment during the diseased condition, may limit the survival of the transplanted stem cells affecting tissue regeneration and even longevity. Carbon nanotubes (CNT) are a new class of nanomaterials, which have been shown to be promising in different areas of nanomedicine for the prevention, diagnosis and therapy of certain diseases, including CNS diseases. In particular, the use of CNTs as substrates/scaffolds for supporting the stem cell differentiation has been an area of active research. Single-walled and multi-walled CNT's have been increasingly used as scaffolds for neuronal growth and more recently for neural stem cell growth and differentiation. This review summarizes recent research on the application of CNT-based materials to direct the differentiation of progenitor and stem cells toward specific neurons and to enhance axon regeneration and synaptogenesis for the effective treatment of CNS injuries. Nonetheless, accumulating data support the use of CNTs as a biocompatible and permissive substrate/scaffold for neural cells and such application holds great potential in neurological research.

The Effect of Agmatine on Expression of IL-1β and TLX Which Promotes Neuronal Differentiation in Lipopolysaccharide-Treated Neural Progenitors

송주현,이원택,박경아,강소망,Bokara Kiran Kumar,이종은 한국뇌신경과학회 2013 Experimental Neurobiology Vol.22 No.4

Differentiation of neural progenitor cells (NPCs) is important for protecting neural cells and brain tissue during inflammation. Interleukin-1 beta (IL-1β) is the most common pro- inflammatory cytokine in brain inflammation, and increased IL-1β levels candecrease the proliferation of NPCs. We aimed to investigate whether agmatine (Agm), a primary polyamine that protects neural cells,could trigger differentiation of NPCs by activating IL-1β in vitro. The cortex of ICR mouse embryos (E14) was dissociated to cultureNPCs. NPCs were stimulated by lipopolysaccharide (LPS). After 6 days, protein expression of stem cell markers and differentiationsignal factors was confirmed by using western blot analysis. Also, immunocytochemistry was used to confirm the cell fate. Agmtreatment activated NPC differentiation significantly more than in the control group, which was evident by the increased expressionof a neuronal marker, MAP2, in the LPS-induced, Agm-treated group. Differentiation of LPS-induced, Agm-treated NPCs wasregulated by the MAPK pathway and is thought to be related to IL-1β activation and decreased expression of TLX, a transcriptionfactor that regulates NPC differentiation. Our results reveal that Agm can promote NPC differentiation to neural stem cells bymodulating IL-1β expression under inflammatory condition, and they suggest that Agm may be a novel therapeutic strategy forneuroinflammatory diseases.

Agmatine Improves Cognitive Dysfunction and Prevents Cell Death in a Streptozotocin-Induced Alzheimer Rat Model

송주현,이종은,허보은,Kiran Kumar Bokara,양원석,조현진,박경아,이원택,이경민 연세대학교의과대학 2014 Yonsei medical journal Vol.55 No.3

Purpose: Alzheimer’s disease (AD) results in memory impairment and neuronal cell death in the brain. Previous studies demonstrated that intracerebroventricular administration of streptozotocin (STZ) induces pathological and behavioral alterationssimilar to those observed in AD. Agmatine (Agm) has been shown to exert neuroprotective effects in central nervous system disorders. In this study, we investigatedwhether Agm treatment could attenuate apoptosis and improve cognitive decline in a STZ-induced Alzheimer rat model. Materials and Methods: We studied the effect of Agm on AD pathology using a STZ-induced Alzheimer rat model. For each experiment, rats were given anesthesia (chloral hydrate 300 mg/kg, ip), followed by a single injection of STZ (1.5 mg/kg) bilaterally into each lateralventricle (5 μL/ventricle). Rats were injected with Agm (100 mg/kg) daily up to two weeks from the surgery day. Results: Agm suppressed the accumulation of amyloid beta and enhanced insulin signal transduction in STZ-induced Alzheimer rats [experimetal control (EC) group]. Upon evaluation of cognitive function by Morris water maze testing, significant improvement of learning and memory dysfunctionin the STZ-Agm group was observed compared with the EC group. Westernblot results revealed significant attenuation of the protein expressions of cleaved caspase-3 and Bax, as well as increases in the protein expressions of Bcl2, PI3K, Nrf2, and γ-glutamyl cysteine synthetase, in the STZ-Agm group. Conclusion:Our results showed that Agm is involved in the activation of antioxidant signalingpathways and activation of insulin signal transduction. Accordingly, Agm may be a promising therapeutic agent for improving cognitive decline and attenuatingapoptosis in AD.

Recombinant hexahistidine arginine decarboxylase (hisADC) induced endogenous agmatine synthesis during stress

Moon, Sung-Ung,Kwon, Ki-Hyo,Kim, Jae-Hwan,Bokara, Kiran Kumar,Park, Kyung Ah,Lee, Won Taek,Lee, Jong-Eun Springer-Verlag 2010 MOLECULAR AND CELLULAR BIOCHEMISTRY - Vol.345 No.1

The expression of human papillomavirus type 16 (HPV16??E7) induces cell cycle arrest and apoptosis in radiation and hypoxia resistant glioblastoma cells.

Moon, Sung-Ung,Choi, Soo Kyoung,Kim, Han Jo,Kumar Bokara, Kiran,Park, Kyung Ah,Lee, Won Taek,Lee, Jong-Eun D. A. Spandidos 2011 MOLECULAR MEDICINE REPORTS Vol.4 No.6

<P>p53 is a widely known tumor-suppressor gene product that plays a key role in apoptotic cell death induced by DNA-damaging chemotherapeutic agents. Human glioma cells with functional p53 are known to be more resistant to 관-radiation. The aim of this study was to investigate whether the mutant glioblastoma cells (U87MG) transfected with human papilloma virus-type 16 E7 (HPV16 E7) genes were capable of increasing sensitivity towards irradiation and hypoxia-induced cell death. The pLXSN retroviral vector expressed HPV-16E7 genes and was infected into the p53 mutated U87MG cell line. A specific amplification band of HPV16 E7 genes was detected in E7 genes and transfected in the U87MG cell line using a reverse transcriptase polymerase chain reaction. The experimental groups included the mutant glioblastoma cell line (U87MG), empty vector (pLXSN) transfected to mutant glioblastoma cell line (U87MG-LXSN), and retrovirus carrying HPV16 E7 genes transfected to the mutant glioblastoma cell line (U87MG-E7). Hypoxic conditions were optimized using LDH assay and the subjects were exposed to hypoxia (16 and 20 h) and irradiation (9 h). Hoechst-propidium iodide (PI) staining results showed that hypoxia and irradiation increased the number of dead cells in the U87MG-E7 cells compared to U87MG and U87MG-LXSN cells. Results of the FACS analysis showed a similar pattern and recorded 80.44 and 58.94% of apoptotic cells in U87MG-E7 and U87MG cells, respectively. Cell cycle analysis by FACS revealed that, following irradiation and hypoxia, cells showed G2-M arrest. Additionally, the Western blot analysis results showed altered expression of E2F-1, Rb and p53 in the irradiation- and hypoxia-induced U87MG-E7 cells compared to U87MG and U87MG LXSN cells. In conclusion, the over-expression of HPV16 E7 genes in U87MG cell lines increasd cell apoptosis and E2F1 expression compared to the HPV non-infected U87MG cells following irradiation and hypoxia. These results indicate that tumor-specific therapies that increase sensitivity towards radiation and hypoxic conditions may be beneficial for suppression of cancers.</P>