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Stroke is a major public health problem leading to high rates of death and disability in adults. Excessive stimulation of N-methyl-D-aspartate receptors (NMDARs) and the resulting neuronal nitric oxide synthase (nNOS) activation are crucial for neuronal injury after stroke insult. However, directly inhibiting NMDARs or nNOS can cause severe side effects because they have key physiological functions in the CNS. Here we show that cerebral ischemia induces the interaction of nNOS with postsynaptic density protein-95 (PSD-95). Disrupting nNOS-PSD-95 interaction via overexpressing the N-terminal amino acid residues 1-133 of nNOS (nNOS-N(1-133)) prevented glutamate-induced excitotoxicity and cerebral ischemic damage. Given the mechanism of nNOS-PSD-95 interaction, we developed a series of compounds and discovered a small-molecular inhibitor of the nNOS-PSD-95 interaction, ZL006. This drug blocked the ischemia-induced nNOS-PSD-95 association selectively, had potent neuroprotective activity in vitro and ameliorated focal cerebral ischemic damage in mice and rats subjected to middle cerebral artery occlusion (MCAO) and reperfusion. Moreover, it readily crossed the blood-brain barrier, did not inhibit NMDAR function, catalytic activity of nNOS or spatial memory, and had no effect on aggressive behaviors. Thus, this new drug may serve as a treatment for stroke, perhaps without major side effects.

Regulation of triglyceride storage and mobilization is critically dependent on the subcellular targeting and trafficking of specific proteins. Recent work demonstrates that this trafficking involves scaffold proteins of the perilipin (Plin) 2 family, including those that are ubiquitously expressed, such as Plin2 (adipose differentiation-related protein) and Plin3 (tail-interacting protein 47, TIP47), and those with restricted expression, such as Plin1 (perilipin) and Plin5 (muscle lipid droplet protein) that appear to have specialized functions (1). Although each Plin homolog has a conserved Plin domain (pfam 03036), amino acid sequences of family members diverge widely outside of this domain (2). Nonetheless, the sequences of individual orthologs are well conserved in mammals and suggest that important functions might be mediated by sequences outside of the Plin domain.We have been investigating how Plin family members organize and regulate the trafficking of lipolytic effector proteins and have focused on Plin1 and Plin5 (3-6). Plin1 is expressed almost exclusively in adipose tissues and plays a central role in the storage of triglyceride and in the rapid mobilization of fatty acids by activators of protein kinase A (1). Recent work indicates that one means by which Plin1 regulates triglyceride storage and mobilization is by controlling the availability of ␣-␤-hydrolase domain-containing 5 (Abhd5), a potent activator of adipose triglyceride lipase (Atgl) (4).In contrast, Plin5 is highly expressed in tissues that have high rates of fatty acid oxidation, such as heart, skeletal muscle, and liver (7,8). Interestingly, expression of Plin5 promotes both triglyceride storage and fatty acid oxidation. Plin5 expression is up-regulated by peroxisome proliferator-activated receptor ␣, and this regulation appears to be part of an expression program that shifts the metabolism of cells from fatty acid storage to oxidation (7).Lipolysis occurs on the surface of intracellular lipid droplets, and several lines of evidence indicate that droplet targeting is critical to the cellular function of Abhd5 and Atgl (9, 10). Abhd5 is targeted to lipid droplets via direct interactions with Plin1 and Plin5 (5, 10, 11). However, unlike Plin1, Plin5 expression promotes the colocalization and interaction of Abhd5 and Atgl in unstimulated cells, which facilitates lipolysis (3-5). It is not known how Plin5 coordinates the interaction of Atgl and Abhd5. On the one hand, Plin5 could bind Atgl5 directly. Alternatively, Atgl might be recruited to the Plin5-containing lipid droplets by virtue of its interaction with Abhd5.In the experiments below, we determined that Atgl interacts with Plin5 but not Plin1. Interestingly, although Plin5 binds both Abhd5 and Atgl, the same Plin5 molecule does not bind both at the same time. Protein complementation experiments, however, indicate that Plin5 forms homo-oligomers and suggest that Abhd5 and Atgl interact as part of this oligomeric structure. Analysis of chimeric and truncated Plin proteins demonstrates ...

Dietary fiber intake can obviously increase stool frequency in patients with constipation. It does not obviously improve stool consistency, treatment success, laxative use and painful defecation.

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