Department of Clinical Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden.
CNS Department, Boehringer Ingelheim Pharma GmbH & Co. KG, 55216 Biberach, Germany.
Int J Mol Sci. 2022 Oct 10;23(19):12056. doi: 10.3390/ijms231912056.
Prosaposin (PSAP) and progranulin (PGRN) are two lysosomal proteins that interact and modulate the metabolism of lipids, particularly sphingolipids. Alterations in sphingolipid metabolism have been found in schizophrenia. Genetic associations of PSAP and PGRN with schizophrenia have been reported. To further clarify the role of PSAP and PGRN in schizophrenia, we examined PSAP and PGRN levels in postmortem cingulate cortex tissue from healthy controls along with patients who had suffered from schizophrenia, bipolar disorder, or major depressive disorder. We found that PSAP and PGRN levels are reduced specifically in schizophrenia patients. To understand the role of PSAP in the cingulate cortex, we used an AAV strategy to knock down PSAP in neurons located in this region. Neuronal PSAP knockdown led to the downregulation of neuronal PGRN levels and behavioral abnormalities. Cingulate-PSAP-deficient mice exhibited increased anxiety-like behavior and impaired prepulse inhibition, as well as intact locomotion, working memory, and a depression-like state. The behavioral changes were accompanied by increased early growth response protein 1 (EGR-1) and activity-dependent cytoskeleton-associated protein (ARC) levels in the sensorimotor cortex and hippocampus, regions implicated in circuitry dysfunction in schizophrenia. In conclusion, PSAP and PGRN downregulation in the cingulate cortex is associated with schizophrenia pathophysiology.
原前体蛋白(PSAP)和颗粒体蛋白前体(PGRN)是两种溶酶体蛋白,它们相互作用并调节脂质代谢,特别是鞘脂代谢。精神分裂症中发现了鞘脂代谢的改变。已经报道了 PSAP 和 PGRN 与精神分裂症的遗传关联。为了进一步阐明 PSAP 和 PGRN 在精神分裂症中的作用,我们检查了健康对照组和患有精神分裂症、双相情感障碍或重度抑郁症的患者死后扣带回皮质组织中的 PSAP 和 PGRN 水平。我们发现 PSAP 和 PGRN 水平在精神分裂症患者中特异性降低。为了了解 PSAP 在扣带回中的作用,我们使用 AAV 策略敲低了该区域神经元中的 PSAP。神经元 PSAP 敲低导致神经元 PGRN 水平下调和行为异常。扣带回 PSAP 缺陷小鼠表现出焦虑样行为增加和前脉冲抑制受损,同时运动、工作记忆和抑郁样状态正常。行为变化伴随着感觉运动皮层和海马体中早期生长反应蛋白 1(EGR-1)和活性依赖性细胞骨架相关蛋白(ARC)水平的增加,这些区域与精神分裂症中的电路功能障碍有关。总之,扣带回皮质中 PSAP 和 PGRN 的下调与精神分裂症的病理生理学有关。