Background: G-protein-Coupled Estrogen Receptor (GPER/GPR30) is a novel membrane-associated estrogen receptor that can induce rapid kinase signaling in various cells. Activation of GPER can prevent hippocampal neuronal cell death following transient global cerebral ischemia (GCI), although the mechanisms remain unclear. In the current study, we sought to address whether GPER activation exerts potent anti-inflammatory effects in the rat hippocampus after GCI as a potential mechanism to limit neuronal cell death. Methods: GCI was induced by four-vessel occlusion in ovariectomized-female SD rats. Specific agonist G1 or antagonist G36 of GPER was administrated using minipump and antisense oligonucleotide (AS) of interleukin-1β receptor antagonist (IL1RA) was administrated using brain infusion kit. Protein expression of IL1RA, NFkB-P65, phosphorylation of CREB (p-CREB), Bcl2, Cleaved-caspase 3 and microglial markers Iba1, CD11b, as well as inflammasome components NLRP3, ASC, Cleaved-caspase 1, and Cle-IL1β in the hippocampal CA1 region were investigated by Immunofluorescent staining and Western blot analysis. The Duo-Link II in situ proximity ligation assay (PLA) was performed to detect the interaction between NLRP3 and ASC. Immunofluorescent staining for NeuN and TUNEL analysis were used to analyze neuronal survival and apoptosis, respectively. We performed Barnes maze and Novel object tests to compare the cognitive function of the rats. Results: The results showed that G1 attenuated GCI-induced elevation of Iba1 and CD11b in the hippocampal CA1 region at 14d reperfusion, and this effect was blocked by G36. G1 treatment also markedly decreased expression of the NLRP3-ASC-Caspase 1 inflammasome and IL1β activation, as well as downstream NFkB signaling, the effects reversed by G36 administration. Intriguingly, G1 caused a robust elevation in neurons of a well-known endogenous anti-inflammatory factor IL1RA, which was reversed by G36 treatment. G1 also enhanced p-CREB level in the hippocampus, a transcription factor known to enhance expression of IL1RA. Finally, in vivo IL1RA-AS abolished the anti-inflammatory, neuroprotective and anti-apoptotic effects of G1 after GCI, and reversed the cognitive-enhancing effects of G1 at 14d after GCI. Conclusions: Taken together, the current results suggest that GPER preserves cognitive function following GCI in part by exerting anti-inflammatory effects and enhancing the defense mechanism of neurons by upregulating IL1RA.

Chronic overfeeding via a high-fat/high-sugar (HFHS) diet decreases wheel running and substantially alters the gut metabolome of C57BL/6J mice. In this study, we tested the hypothesis that fecal microbial transplants can modulate the effect of diet on wheel running. Methods: Singly housed, 6-wk-old male C57BL/6J mice were fed either a grain-based diet (CHOW) or HFHS diet and provided a running wheel for 13 wk. Low-active, HFHS-exposed mice were then either switched to a CHOW diet and given an oral fecal microbial transplant from mice fed the CHOW diet, switched to a CHOW diet and given a sham transplant, or remained on the HFHS diet and given a fecal microbial transplant from mice fed the CHOW diet. Total wheel running, nutrient intake, body composition, fecal microbial composition, fecal metabolite composition, and liver steatosis were measured at various times throughout the study. Results: We found that an HFHS diet decreases wheel running activity, increases body fat, and decreases microbial alpha diversity compared with a CHOW diet. Improvements in wheel running, body composition, and microbial alpha diversity were accomplished within 2 wk for mice switched from an HFHS diet to a CHOW diet with no clear evidence of an added benefit from fecal transplants. A fecal transplant from mice fed a CHOW diet without altering diet did not improve wheel running or body composition. Wheel running, body composition, fecal microbial composition, fecal metabolite composition, and liver steatosis percentage were primarily determined by diet. Conclusions: Our results suggest that diet is a primary mediator of wheel running with no clear effect from fecal microbial transplants.

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Background: G-protein-Coupled Estrogen Receptor (GPER/GPR30) is a novel membrane-associated estrogen receptor that can induce rapid kinase signaling in various cells. Activation of GPER can prevent hippocampal neuronal cell death following transient global cerebral ischemia (GCI), although the mechanisms remain unclear. In the current study, we sought to address whether GPER activation exerts potent anti-inflammatory effects in the rat hippocampus after GCI as a potential mechanism to limit neuronal cell death. Methods: GCI was induced by four-vessel occlusion in ovariectomized-female SD rats. Specific agonist G1 or antagonist G36 of GPER was administrated using minipump and antisense oligonucleotide (AS) of interleukin-1β receptor antagonist (IL1RA) was administrated using brain infusion kit. Protein expression of IL1RA, NFkB-P65, phosphorylation of CREB (p-CREB), Bcl2, Cleaved-caspase 3 and microglial markers Iba1, CD11b, as well as inflammasome components NLRP3, ASC, Cleaved-caspase 1, and Cle-IL1β in the hippocampal CA1 region were investigated by Immunofluorescent staining and Western blot analysis. The Duo-Link II in situ proximity ligation assay (PLA) was performed to detect the interaction between NLRP3 and ASC. Immunofluorescent staining for NeuN and TUNEL analysis were used to analyze neuronal survival and apoptosis, respectively. We performed Barnes maze and Novel object tests to compare the cognitive function of the rats. Results: The results showed that G1 attenuated GCI-induced elevation of Iba1 and CD11b in the hippocampal CA1 region at 14d reperfusion, and this effect was blocked by G36. G1 treatment also markedly decreased expression of the NLRP3-ASC-Caspase 1 inflammasome and IL1β activation, as well as downstream NFkB signaling, the effects reversed by G36 administration. Intriguingly, G1 caused a robust elevation in neurons of a well-known endogenous anti-inflammatory factor IL1RA, which was reversed by G36 treatment. G1 also enhanced p-CREB level in the hippocampus, a transcription factor known to enhance expression of IL1RA. Finally, in vivo IL1RA-AS abolished the anti-inflammatory, neuroprotective and anti-apoptotic effects of G1 after GCI, and reversed the cognitive-enhancing effects of G1 at 14d after GCI. Conclusions: Taken together, the current results suggest that GPER preserves cognitive function following GCI in part by exerting anti-inflammatory effects and enhancing the defense mechanism of neurons by upregulating IL1RA.