Soo Ryeong Jeong

Publications (2)7.44 Total impact

• Article: Hepatocyte growth factor reduces astrocytic scar formation and promotes axonal growth beyond glial scars after spinal cord injury.

  Soo Ryeong Jeong, Min Jung Kwon, Hwan Goo Lee, Eun Hye Joe, Jae Ho Lee, Sung Soo Kim, Haeyoung Suh-Kim, Byung G Kim
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  ABSTRACT: The formation of glial scars impedes growth of regenerating axons after CNS injuries such as spinal cord injury (SCI). Hepatocyte growth factor (HGF), originally identified as a mitogen for hepatocytes, exerts pleiotropic functions in the nervous system. HGF has been implicated in peripheral wound healing via regulation of the transforming growth factor beta (TGFβ), which is also a potent inducer of glial scar formation in CNS. In the present study, we found that HGF completely blocked secretion of TGFβ1 and β2 from activated astrocytes in culture. HGF also prevented expression of specific chondroitin sulfate proteoglycan (CSPG) species. To determine whether HGF inhibits glial scar formation in an in vivo SCI model, HGF overexpressing mesenchymal stem cells (HGF-MSCs) were transplanted into hemisection spinal cord lesions at C4. Transplantation of HGF-MSCs markedly diminished TGFβ isoform levels and reduced the extent of astrocytic activation. In addition, HGF-MSCs also significantly decreased neurocan expression and glycosaminoglycan chain deposition around hemisection lesions. Furthermore, animals treated with HGF-MSCs showed increased axonal growth beyond glial scars and improvement in recovery of forepaw function. Our results indicate that anti-glial scar effects of HGF, together with its known neurotrophic functions, could be utilized to ameliorate functional deficits following SCI.
  Experimental Neurology 10/2011; 233(1):312-22. · 4.70 Impact Factor
• Article: Endogenous expression of interleukin-4 regulates macrophage activation and confines cavity formation after traumatic spinal cord injury.

  Seung Ihm Lee, Soo Ryeong Jeong, Young Mi Kang, Dae Hee Han, Byung Kwan Jin, Uk Namgung, Byung G Kim
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  ABSTRACT: Traumatic spinal cord injury (SCI) triggers inflammatory reactions in which various types of cells and cytokines are involved. Several proinflammatory cytokines are up-regulated after SCI and play crucial roles in determining the extent of secondary tissue damage. However, relatively little is known about antiinflammatory cytokines and their roles in spinal cord trauma. Recent studies have shown that an antiinflammatory cytokine, interleukin-4 (IL-4), is expressed and exerts various modulatory effects in CNS inflammation. We found in the present study that IL-4 was highly expressed at 24 hr after contusive SCI in rats and declined thereafter, with concurrent up-regulation of IL-4 receptor subunit IL-4alpha. The majority of IL-4-producing cells were myeloperoxidase-positive neutrophils. Injection of neutralizing antibody against IL-4 into the contused spinal cord did not significantly affect the expression levels of proinflammatory cytokines such as IL-1beta, IL-6, and tumor necrosis factor-alpha or other antiinflammatory cytokines such as IL-10 and transforming growth factor-beta. Instead, attenuation of IL-4 activity led to a marked increase in the extent of ED1-positive macrophage activation along the rostrocaudal extent at 7 days after injury. The enhanced macrophage activation was preceded by an increase in the level of monocyte chemoattractant protein-1 (MCP-1/CCL2). Finally, IL-4 neutralization resulted in more extensive cavitation at 4 weeks after injury. These results suggest that endogenous expression of antiinflammatory cytokine IL-4 regulates the extent of acute macrophage activation and confines the ensuing secondary cavity formation after spinal cord trauma.
  Journal of Neuroscience Research 08/2010; 88(11):2409-19. · 2.74 Impact Factor