Lower expressing transporter alleles, directly and by increasing the impact of stressful life events on severity, explain 31% of the variance in major depression severity. The biological phenotype responsible for these effects remains to be elucidated.

Abnormal accumulation of ␤-amyloid (A␤) is the major neuropathological hallmark of Alzheimer's disease (AD). However, the mechanisms underlying aberrant A␤ formation in AD remain unclear. We showed previously that inhibition of monoacylglycerol lipase (MAGL), the primary enzyme that metabolizes the endocannabinoid 2-arachidonoylglycerol (2-AG) in the brain, robustly reduces A␤ by inhibiting ␤-site amyloid precursor protein cleaving enzyme 1 (BACE1), a key enzyme responsible for A␤ formation. However, the molecular mechanisms responsible for suppression of BACE1 by inhibition of 2-AG metabolism are largely unknown. We demonstrate here that expression of the noncoding small RNA miR-188-3p that targets BACE1 was significantly downregulated both in the brains of AD humans and APP transgenic (TG) mice, a mouse model of AD. The downregulated miR-188-3p expression was restored by MAGL inhibition. Overexpression of miR-188-3p in the hippocampus reduced BACE1, A␤, and neuroinflammation and prevented deteriorations in hippocampal basal synaptic transmission, long-term potentiation, spatial learning, and memory in TG mice. 2-AG-induced suppression of BACE1 was prevented by miR-188-3p loss of function. Moreover, miR-188-3p expression was upregulated by 2-AG or peroxisome proliferator-activated receptor-␥ (PPAR␥) agonists and suppressed by PPAR␥ antagonism or NF-B activation. Reducing A␤ and neuroinflammation by MAGL inhibition was occluded by PPAR␥ antagonism. In addition, BACE1 suppression by 2-AG and PPAR␥ activation was eliminated by knockdown of NF-B. Our study provides a novel molecular mechanism underlying improved synaptic and cognitive function in TG mice by 2-AG signaling, which upregulates miR-188-3p expression through PPAR␥ and NF-B signaling pathway, resulting in suppressions of BACE1 expression and A␤ formation.

Aortic aneurysm is an asymptomatic disease with dire outcomes if undiagnosed. Aortic aneurysm rupture is a significant cause of death worldwide. To date, surgical repair or endovascular repair (EVAR) is the only effective treatment for aortic aneurysm, as no pharmacological treatment has been found effective. Aortic aneurysm, a focal dilation of the aorta, can be formed in the thoracic (TAA) or the abdominal (AAA) region; however, our understanding as to what determines the site of aneurysm formation remains quite limited. The extracellular matrix (ECM) is the noncellular component of the aortic wall, that in addition to providing structural support, regulates bioavailability of an array of growth factors and cytokines, thereby influencing cell function and behavior that ultimately determine physiological or pathological remodeling of the aortic wall. Here, we provide an overview of the ECM proteins that have been reported to be involved in aortic aneurysm formation in humans or animal models, and the experimental models for TAA and AAA and the link to ECM manipulations. We also provide a comparative analysis, where data available, between TAA and AAA, and how aberrant ECM proteolysis versus disrupted synthesis may determine the site of aneurysm formation.

Emerging evidence suggests that the risk of developing chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease, is significantly increased in military personnel and contact sports players who have been exposed to repetitive trauma brain injury (TBI). Unfortunately there are no effective medications currently available for prevention and treatment of CTE. Here we demonstrate that inhibition of monoacylglycerol lipase (MAGL), the key enzyme that metabolizes the endocannabinoid 2-arachidonoylglycerol (2-AG) in the brain, significantly reduced CTE-like neuropathologic changes in a mouse model of repetitive mild closed head injury (rmCHI). Inhibition of 2-AG metabolism promoted neurologic recovery following rmCHI and reduced proinflammatory cytokines, astroglial reactivity, expression of amyloid precursor protein and the enzymes that make Aβ, as well as formation of Aβ. Importantly, neurodegeneration, TDP-43 protein aggregation, and tau phosphorylation, which are the neuropathologic hallmarks of CTE, were significantly suppressed by MAGL inactivation. Furthermore, alterations in expression of glutamate receptor subunits and impairments in basal synaptic transmission, long-term synaptic plasticity, and spatial learning and memory were recovered by inhibition of 2-AG metabolism in animals exposed to rmCHI. Our results suggest that MAGL inhibition, which boosts 2-AG and reduces 2-AG metabolites prostaglandins in the brain, may lead to a new therapy for CTE.

No abstract