Sakai Kenta, Takata Fuyuko, Iwao Takuro, Yasunaga Miho, Yamanaka Gaku, Kataoka Yasufumi, Dohgu Shinya
Department of Pharmaceutical Education Center, Yokohama University of Pharmacy, Kanagawa, Japan.
Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan.
IBRO Neurosci Rep. 2025 Jun 1;19:54-61. doi: 10.1016/j.ibneur.2025.05.017. eCollection 2025 Dec.
Astrocytes maintain glutamate homeostasis in the central nervous system (CNS) via glutamate uptake through Na-dependent excitatory amino acid transporters (EAAT1 and EAAT2), and this process is regulated by several CNS cell types. However, it is unclear whether brain pericytes regulate glutamate uptake by astrocytes. Therefore, in this study, we aimed to investigate the effects of pericytes on the uptake of extracellular glutamate by astrocytes using an co-culture model of human brain-derived pericytes and astrocytes (pericyte co-cultures). The [H]-L-glutamate ([H]-L-Glu) uptake rate of astrocytes in pericyte co-cultures was significantly higher than that in astrocyte monocultures. Under Na-free conditions, [H]-L-Glu uptake by astrocytes was significantly inhibited in astrocyte monocultures and pericyte co-cultures. The inhibitory effect of Na depletion on glutamate uptake by astrocytes was more pronounced in pericyte co-cultures than in astrocyte monocultures. These findings suggest that glutamate uptake by astrocytes through the Na-dependent transporter EAATs is upregulated by pericytes. Treatment with dihydrokainic acid, a selective inhibitor of EAAT2, significantly inhibited [H]-L-Glu uptake by astrocytes in pericyte co-cultures but not in astrocyte monocultures. Treatment with UCPH-101, a selective inhibitor of EAAT1, significantly inhibited [H]-L-Glu uptake by astrocytes in both monocultures and pericyte co-cultures. The UCPH-101-induced reduction in [H]-L-Glu uptake by astrocytes in pericyte co-cultures was similar to that observed in astrocyte monocultures. These results suggest that pericytes upregulate glutamate uptake via EAAT2 in astrocytes. Furthermore, [H]-L-Glu uptake in astrocytes significantly increased when astrocytes were treated with pericyte-conditioned medium. This finding suggests that pericyte-derived soluble factors contribute to the upregulation of astrocytic glutamate uptake. To our knowledge, this is the first study to report that pericyte-released mediators upregulate the EAAT2-dependent uptake of extracellular glutamate in astrocytes.
星形胶质细胞通过依赖钠的兴奋性氨基酸转运体（EAAT1和EAAT2）摄取谷氨酸来维持中枢神经系统（CNS）中的谷氨酸稳态，并且这一过程受几种中枢神经系统细胞类型的调节。然而，尚不清楚脑周细胞是否调节星形胶质细胞对谷氨酸的摄取。因此，在本研究中，我们旨在使用人脑源性周细胞和星形胶质细胞的共培养模型（周细胞共培养物）来研究周细胞对星形胶质细胞摄取细胞外谷氨酸的影响。周细胞共培养物中星形胶质细胞的[H]-L-谷氨酸（[H]-L-Glu）摄取率显著高于星形胶质细胞单培养物中的摄取率。在无钠条件下，星形胶质细胞单培养物和周细胞共培养物中星形胶质细胞对[H]-L-Glu的摄取均受到显著抑制。钠缺失对星形胶质细胞谷氨酸摄取的抑制作用在周细胞共培养物中比在星形胶质细胞单培养物中更明显。这些发现表明，周细胞上调了星形胶质细胞通过依赖钠的转运体EAATs对谷氨酸的摄取。用EAAT2的选择性抑制剂二氢海因酸处理，显著抑制了周细胞共培养物中星形胶质细胞对[H]-L-Glu的摄取，但对星形胶质细胞单培养物中的摄取没有影响。用EAAT1的选择性抑制剂UCPH-101处理，显著抑制了单培养物和周细胞共培养物中星形胶质细胞对[H]-L-Glu的摄取。UCPH-101诱导的周细胞共培养物中星形胶质细胞对[H]-L-Glu摄取的减少与在星形胶质细胞单培养物中观察到的相似。这些结果表明，周细胞通过EAAT2上调星形胶质细胞对谷氨酸的摄取。此外，当用周细胞条件培养基处理星形胶质细胞时，星形胶质细胞中[H]-L-Glu的摄取显著增加。这一发现表明，周细胞衍生的可溶性因子有助于上调星形胶质细胞对谷氨酸的摄取。据我们所知，这是第一项报道周细胞释放的介质上调星形胶质细胞中依赖EAAT2摄取细胞外谷氨酸的研究。
