TAT-mGluR1 Attenuation of Neuronal Apoptosis through Prevention of MGluR1α Truncation after Experimental Subarachnoid Hemorrhage.

Excessive glutamate-mediated overactivation of metabotropic glutamate receptor 1 (mGluR1) plays a leading role in neuronal apoptosis following subarachnoid hemorrhage (SAH). TAT-mGluR1, a fusion peptide consisting of a peptide spanning the calpain cleavage site of mGluR1α and the trans-activating regulatory protein (TAT) of HIV, effectively blocks mGluR1α truncation and protects neurons against excitotoxic damage. This study investigated the effects of TAT-mGluR1 on neuronal apoptosis in the rat SAH model. Here, we report that SAH caused activation of calpain and truncation of mGluR1α; intraperitoneally administered TAT-mGluR1 did not affect calpain activity, while it blocked truncation of mGluR1α after SAH. Intraperitoneally administered FITC-labeled TAT-mGluR1 was colocalized with mGluR1α in thecortex after SAH. Furthermore, TAT-mGluR1 significantly improved the neurological deficit, increased p-PI3K, p-Akt, and p-GSK3ß, downregulated Bax, upregulated Bcl-2, and reduced cortical apoptosis in the basal cortex at 24 h after SAH. These findings indicated that TAT-mGluR1 acted against SAH-induced cell apoptosis through preventing mGluR1α truncation.

The GluN1/GluN2B NMDA receptor and metabotropic glutamate receptor 1 negative allosteric modulator has enhanced neuroprotection in a rat subarachnoid hemorrhage model.

Excessive glutamate in cerebrospinal fluid after subarachnoid hemorrhage (SAH) causes excitotoxic damage through calcium overloading and a subsequent apoptotic cascade. GluN1/GluN2B containing N-methyl-Daspartate (NMDA) receptor and metabotropic glutamate receptor 1 (mGluR1) can play a leading role in glutamate-mediated excitotoxicity. Here we report that Ifenprodil (100µM), a negative allosteric modulator (NAM) of GluN1/GluN2B NMDA receptors, and JNJ16259685 (10µM), a NAM of mGluR1, have an additive efficacy against glutamate (100µM)-induced Ca2+ release and cell apoptosis in primary cortical, hippocampal, and cerebellar granule neurons. Compared with intraperitoneal injection of Ifenprodil (10mg/kg) and JNJ16259685 (1mg/kg) separately, the combination therapy of Ifenprodil plus JNJ16259685 significantly improves the neurological deficit at 24h and 72h after experimental SAH. It reduces the number of TUNEL/DAPI-positive and activated caspase-3/NeuN-positive cells in cortical and hippocampal CA1 regions at 72h, decreases levels of glutamate in cerebrospinal fluid at 72h, and reduces the mitochondrial Ca2+ concentration. Meanwhile, the combination therapy attenuates apoptosis as shown by an increased Bcl-2 expression, decreased Bax expression and release of cytochrome c, and reduction of cleaved caspase-9 and caspase-3 at 24h after SAH. These findings indicate that targeting both the intracellular Ca2+ overloading and neuronal apoptosis using the Ifenprodil and JNJ16259685 is a promising new therapy for SAH.

Roflumilast Reduces Cerebral Inflammation in a Rat Model of Experimental Subarachnoid Hemorrhage.

Roflumilast, a selective inhibitor for PDE4, is approved by FDA as an anti-inflammation drug for treatment of chronic obstructive pulmonary disease (COPD). This study investigates the effects of roflumilast on cerebral inflammation in the rat SAH model. Here, we show that subcutaneous administration of roflumilast (3 mg/kg) significantly improved the neurological deficits. Measurement of evans blue extravasation and brain water content revealed a significant reduction of blood-brain barrier permeability and brain edema. Importantly, roflumilast treatment remarkably decreased levels of IL-1ß, IL-6, and TNF-α and the number of apoptotic neurons in the brain after SAH. These results indicate that roflumilast is effective in treating cerebral inflammation following SAH.

Carnosine Attenuates Brain Oxidative Stress and Apoptosis After Intracerebral Hemorrhage in Rats.

Carnosine, an endogenous dipeptide (ß-alanyl-L-histidine), exerts multiple neuroprotective properties, but its role in intracerebral hemorrhage (ICH) remains unclear. This study investigates the effect of Carnosine on brain injury using the rat ICH model, which is established by type IV collagenase caudatum infusion. The results indicate that intraperitoneal administration of Carnosine (1000 mg/kg) significantly attenuates brain edema, blood-brain barrier (BBB) disruption, oxidative stress, microglia activation and neuronal apoptosis of perihematoma at 72 h following ICH in rats models, as convinced by preventing the disruption of tight junction protein ZO-1, occludin and claudin-5, followed by the decrease of ROS, MDA, 3-NT, 8-OHDG level and the increase of GSH-Px and SOD activity, then followed by the decline of Iba-1, ED-1, active caspase-3 and TUNEL positive cells and the decrease of IL-1ß, IL-6, TNF-α, active caspase-3 and cytochrome c level. Our results suggest that Carnosine may provide neuroprotective effect after experimental ICH in rat models.

Generation and characterization of bovine bone marrow-derived macrophage cell line.

Macrophages, as the forefront of innate immune defense, have an important role in the host responses to mycobacterial infection. Therefore, a stable macrophage cell line is needed for future bovine immune system research on the bacterial infection. In this study, we established a bovine macrophage cell line by introducing the human telomerase reverse transcriptase (hTERT) gene into bovine bone marrow-derived macrophages (bBMMs). The TERT-bBMMs cells expressed macrophage surface antigen (CD11b, CD282) and upregulated expression of the cytokines IL-1ß, IL-6, IL-10, IL-12, TNF-α in response to bacterial invasion. These results demonstrate that this cell line provide reliable cell model system for future studies on interactions between the bovine macrophages and Mycobacterium tuberculosis.