Jin Suk Lee

Expression of GABAA receptor β2/3 subunits in the rat major pelvic ganglion

Several pharmacological and physiological studies have suggested that GABA(A) receptors (GABA(A) Rs) may exist in the rat major pelvic ganglion (MPG), a large coalescent pelvic ganglion that contains both sympathetic and parasympathetic components which innervates pelvic organs. However, the presence of GABA(A) R in the MPG has never been demonstrated directly by morphological studies. In the present study, we used immunohistochemistry to demonstrate the existence of GABA(A) R beta2/3 subunits for the first time in the rat MPG. We also analyzed the neurochemical properties of MPG neurons expressing GABA(A) R beta2/3 subunits. GABA(A) R beta2/3-immunoreactive (-IR) neurons occupied 27.4+/-7.0% of the whole neuronal population, and many of these (77.6%) were co-localized with tyrosine hydroxylase (TH). Likewise, most (86.5%) of TH-IR neurons were GABA(A) R beta2/3-positive. GABA(A) R beta2/3 subunits were also expressed in a few VIP- or NOS-IR neurons, the cholinergic or non-adrenergic, non-cholinergic (NANC) neurons. These results suggest that GABA(A) Rs are involved in the modulation of most sympathetic, noradrenergic neurons and also a subset of VIP and NOS neurons of the rat MPG.

Transplantation of human mesenchymal stem cells into the cisterna magna and its neuroprotective effects in a parkinsonian animal model

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases in the elderly, and therefore, the demand for effective therapies against PD has greatly increased. Therapeutic applications of stem cells have been considered to be one of the promising approaches in PD therapy. In the present study, the neuroprotective effects of hMSCs were evaluated in a parkinsonian rat model. The animal model was established by injecting 6-hydroxydopamine into the striatum of rats. Two weeks later, cultured hMSCs were transplanted into the cisterna magna. We subsequently identified changes in the expression of inflammatory cytokines, neurotrophic factors, microglial activation, and the survival rate of dopaminergic neurons in SNc. Behavioral recovery was also examined. The results indicated that hMSC transplantation increased the expression of anti-inflammatory cytokines as well as neurotrophic factors, and decreased the number of activated microglia. Compared to the sham-grafted group, relatively large numbers of TH-positive neurons were found in the ipsilateral SNc, and amphetamine-induced asymmetrical rotation was significantly reduced after hMSC transplantation. These findings suggest that hMSCs might be neuroprotective, probably through up-regulation of neurotrophic factors and anti-inflammatory cytokines, and this could have a functional impact in reversing PD symptoms.

Adipose tissue-derived mesenchymal stem cells cultured at high cell density express brain-derived neurotrophic factor and exert neuroprotective effects in a 6-hydroxydopamine rat model of Parkinson’s disease

Mesenchymal stem cells (MSCs) secrete neurotrophic factors, and have been reported to improve functional outcomes in animal models of neurodegenerative diseases such as cerebral ischemia, stroke, spinal cord lesions, and Parkinson’s disease. Previously, we found that adipose tissue-derived mesenchymal stem cells (ASCs) cultured at high cell density (HD-ASCs) expressed interferon-beta (IFN-β). Here we demonstrate that ASCs expressing IFN-β also express brain-derived neurotrophic factor (BDNF). Growth rates of neuroblastoma cells (SK-N-BE(2)C) were increased when co-cultured with HD-ASCs or treated with concentrated medium obtained from HD-ASCs (HD-ASC-CM). The HD-ASC-CM induced AKT phosphorylation in SK-N-BE(2)C cells, and AKT inhibition by Ly294002 reduced cell viability of SK-N-BE(2)C cells. Additionally, a protective effect on SK-N-BE(2)C cells exposed to 6-hydroxydopamine (6-OHDA) was observed in the HD-ASC-CM or brain-derived neurotrophic factor (BDNF) treated cells. The protective effect of the HD-ASC-CM was neutralized by anti-BDNF antibody. In the 6-OHDA-induced Parkinson’s disease rat model, ASCs reduced amphetamine-induced rotations and a greater number of tyrosine hydroxylase (TH)-positive cells were observed in the HD-ASCs-injected group compared with sham controls and the low density cultured ASC-injected group. Moreover, the expression of BDNF, nerve growth factor (NGF), TH, and proliferating cell nuclear antigen (PCNA) in ipsilateral midbrain tissues including substantia nigra pars compacta (SNc) was increased by transplantation of HD-ASCs. These data indicate that HD-ASCs may induce neuroprotective effects through BDNF expression and subsequent increase of proliferation in neuronal cells both in vitro and in vivo.