Kawata A, Nakane M, Deguchi T
Department of Neurology, Tokyo Metropolitan Neurological Hospital, Japan.
Brain Res Dev Brain Res. 1990 Dec 1;57(1):129-37. doi: 10.1016/0165-3806(90)90192-2.
Choline acetyltransferase (CAT) activity increased 11-fold in co-cultures of spinal cord and muscle cells from fetal mice relative to cultures of spinal cord cells alone. The addition of transforming growth factor-beta (TGF-beta) to the medium at 30 pM throughout the culture period inhibited the increase of CAT activity in the co-cultures, but did not affect the activity in cultures of spinal cord cells alone. TGF-beta did not inhibit glutamic acid decarboxylase activity in the co-cultures. Other growth factors such as epidermal growth factor, fibroblast growth factor and beta-NGF had little or no effect on CAT activity. TGF-beta markedly inhibited the fusion of myoblasts to myotubes and the expression of marker enzymes for muscle differentiation. When TGF-beta was included during muscle culture and removed before inoculation with spinal cord cells, myoblasts did not subsequently form myotubes. CAT activity in the spinal cord cells, however, markedly increased in co-cultures with the undifferentiated myoblasts. When TGF-beta was added to the co-cultures after myotube formation was complete, the increase in CAT activity was inhibited according to the length of TGF-beta treatment. These results suggest that TGF-beta inhibits the muscle-induced stimulation of CAT activity by inhibiting the production, secretion and/or action of trophic factors from muscle.
与单独培养的脊髓细胞相比，来自胎鼠的脊髓和肌肉细胞共培养物中胆碱乙酰转移酶（CAT）活性增加了11倍。在整个培养期间，向培养基中添加30 pM的转化生长因子-β（TGF-β）可抑制共培养物中CAT活性的增加，但不影响单独培养的脊髓细胞中的活性。TGF-β不抑制共培养物中的谷氨酸脱羧酶活性。其他生长因子，如表皮生长因子、成纤维细胞生长因子和β-神经生长因子对CAT活性几乎没有影响。TGF-β显著抑制成肌细胞与肌管的融合以及肌肉分化标志物酶的表达。当在肌肉培养期间加入TGF-β并在接种脊髓细胞之前去除时，成肌细胞随后不会形成肌管。然而，在与未分化的成肌细胞共培养时，脊髓细胞中的CAT活性显著增加。当肌管形成完成后向共培养物中添加TGF-β时，CAT活性的增加根据TGF-β处理的时间长度而受到抑制。这些结果表明，TGF-β通过抑制肌肉中营养因子的产生、分泌和/或作用来抑制肌肉诱导的CAT活性刺激。
