The deficiency of Maged1 attenuates Parkinson's disease progression in mice

Melanoma-associated antigen D1 (Maged1) has critical functions in the central nervous system in both developmental and adult stages. Loss of Maged1 in mice has been linked to depression, cognitive disorder, and drug addiction. However, the role of Maged1 in Parkinson's disease (PD) remains unclear. In this study, we observed that Maged1 was expressed in the dopaminergic (DA) neurons of the substantia nigra in mice and humans, which could be upregulated by the in vivo or in vitro treatment with 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 1-Methyl-4-phenylpyridinium iodide (MPP+). Genetic ablation of Maged1 in mice attenuated motor deficits, the loss of DA neurons, and disease progression induced by MPTP. Moreover, Maged1 deficiency protected DA neurons against MPP+-induced toxicity in primary cultured cells. Mechanistically, loss of Maged1 upregulated the Akt signaling pathway and downregulated the mTOR signaling pathway in SH-SY5Y cells, which may in turn attenuate the cell apoptosis and impairment of autophagy. Consistent with it, the degeneration of midbrain and striatum among elderly Maged1 knockout mice was relatively mild compared to those in wild-type mice under physiological conditions. Taken together, this study suggested that Maged1 deficiency inhibited apoptosis and enhanced autophagy, which may provide a new potential target for the therapy of PD.

Protein phosphatase 2A deficiency in hippocampal CA1 inhibits priming effect of morphine on conditioned place preference in mice

Studies have shown that protein phosphorylation plays an important role in morphine abuse. However, the neurobiological mechanism of protein phosphatase 2A (PP2A) underlying the morphine-priming process is still unclear. Here we constructed T29-2-Cre; PP2Afl/fl conditional knockout mice (KO) and investigated the role of hippocampal PP2A in morphine priming. We observed that the deficit of PP2A inhibited the priming behavior of morphine and blocked the priming-induced long-term potentiation (LTP) in the hippocampus of KO mice. Moreover, the expression levels of Rack1 and the membrane GluN2B were significantly reduced in the nucleus accumbens of KO mice compared with those in the control mice, which may be attributed to the decreased HDAC4 in the hippocampus of KO mice. Consistent with it, the similar inhibited priming effects were also observed in the wild-type mice treated with sodium butyrate (NaB)-a nonspecific inhibitor of histone deacetylases-3 h after morphine administration. Taken together, our results suggest that hippocampal PP2A may be involved in morphine priming through the PP2A/HDAC4/Rack1 pathway.

[Perioperative stroke effectively treated by an acute stroke team including anesthesia department: a case report]

Perioperative stroke is cerebral infarction occurring in the perioperative period. The incidence of perioperative stroke in non-cardiac, and non-neurologic surgery is about 0.7%, but the mortality can be as high as 26% to 40%. The outcome of the patients with perioperative stroke can be disastrous. Here we report a case of perioperative ischemic stroke that occurred after surgery of lumbar decompression and pedical screw fixation. A 76-year-old female admitted to our hospital because of lumbar spinal stenosis. Her medical history included hypertension and diabetes for ten years. Her personal history included a smoking history of 60 years by 2 cigarettes per day, not quitting. Her carotid artery ultrasound showed multiple low echo plaques on the right side and multiple high echo plaques on the left side of the carotid artery, but without distinct stenosis. Other examinations and tests showed no distinct abnormality. She went on a lumbar decompression and pedical screw fixation uneventfully. The blood loss was 400 mL and autologous blood transfusion 150 mL. The arterial blood pressure (ABP) maintained during 100-130 mmHg/60-80 mmHg (1 mmHg=0.133 kPa). Sixty minutes after she recovered from general anesthesia, the patient developed symptoms of slurred speech and right limbs weakness. The anesthesio-logist evaluated the patient immediately with National Institute of Health Stroke Scale (NIHSS). The NIHSS score was 11 and a stroke was highly suspected. The acute stroke team was therefore initiated and fast responded. Within 4 h, digital subtraction angiography (DSA) was proceeded, which showed the M1 segment of the left middle cerebral artery was occluded and the local stenosis of her right middle cerebral artery was up to 80%. After the successful embolectomy by Solitaire stent, the left middle cerebral artery reflowed and the forward blood flow was thrombolysis in myocardial infarction (TIMI) grade 3. The patient was discharged after 33 days after the surgery with a NIHSS of 9. Our case provides an example that an acute stroke team that included the department of anesthesiology can be beneficial to the patients' perioperative strokes. During the perioperative period, anesthesiologists should be included into the acute stroke team, because anesthesiologists and anesthesia nurses might be first observers of those early onset strokes. Our case also put forward this thought that a standard peri-operative stroke evaluation tool, like NIHSS, should be discussed and applied to facilitate and accelerate the initiation of perioperative acute stroke team.