Abstract:It is widely accepted that intersexual differences occur in cognitive domains, e.g., in spatial learning and memory. The hippocampus plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. However, it still remains unknown whether the hippocampal proteomic profiling differs between males and females. In this study, we investigated the intersexual differences in protein expression of hippocampi using the two-dimensional electrophoresis analysi… Show more
“…Therefore, while estrous cycle stage did appear to impact both the dHPC proteome and phosphoproteome, the magnitude of this hormone-dependent impact was much greater on total versus phosphorylated protein levels. This is consistent with reports of significant estrous cycle-dependent fluctuations in protein and transcript levels within this brain region 43 , 44 , 52 – 54 and others such as the medial prefrontal cortex 55 . Figure 4 Estrous cycle-dependent total and phosphoprotein expression in the dHPC.…”
Numerous emotional and cognitive processes mediated by the hippocampus present differences between sexes and can be markedly influenced by hormonal status in males and females of several species. In rodents, the dorsal hippocampus (dHPC) is known to contribute to the rapid antidepressant actions of the NMDA receptor antagonist ketamine. We and others have demonstrated a greater sensitivity to the fast-acting antidepressant ketamine in female versus male rats that is estrogen- and progesterone-dependent. However, the underlying mechanisms remain unclear. Using an acute low dose (2.5 mg/kg) of ketamine that is behaviorally effective in female but not male rats, a label-free phosphoproteomics approach was employed to identify ketamine-induced changes in signaling pathway activation and phosphoprotein abundance within the dHPC of intact adult male rats and female rats in either diestrus or proestrus. At baseline, males and females showed striking dissimilarities in the dHPC proteome and phosphoproteome related to synaptic signaling and mitochondrial function—differences also strongly influenced by cycle stage in female rats. Notably, phosphoproteins enriched in PKA signaling emerged as being both significantly sex-dependent at baseline and also the primary target of ketamine-induced protein phosphorylation selectively in female rats, regardless of cycle stage. Reduced phosphoprotein abundance within this pathway was observed in males, suggesting bi-directional effects of low-dose ketamine between sexes. These findings present biological sex and hormonal milieu as critical modulators of ketamine’s rapid actions within this brain region and provide greater insight into potential translational and post-translational processes underlying sex- and hormone-dependent modulation of ketamine’s therapeutic effects.
“…Therefore, while estrous cycle stage did appear to impact both the dHPC proteome and phosphoproteome, the magnitude of this hormone-dependent impact was much greater on total versus phosphorylated protein levels. This is consistent with reports of significant estrous cycle-dependent fluctuations in protein and transcript levels within this brain region 43 , 44 , 52 – 54 and others such as the medial prefrontal cortex 55 . Figure 4 Estrous cycle-dependent total and phosphoprotein expression in the dHPC.…”
Numerous emotional and cognitive processes mediated by the hippocampus present differences between sexes and can be markedly influenced by hormonal status in males and females of several species. In rodents, the dorsal hippocampus (dHPC) is known to contribute to the rapid antidepressant actions of the NMDA receptor antagonist ketamine. We and others have demonstrated a greater sensitivity to the fast-acting antidepressant ketamine in female versus male rats that is estrogen- and progesterone-dependent. However, the underlying mechanisms remain unclear. Using an acute low dose (2.5 mg/kg) of ketamine that is behaviorally effective in female but not male rats, a label-free phosphoproteomics approach was employed to identify ketamine-induced changes in signaling pathway activation and phosphoprotein abundance within the dHPC of intact adult male rats and female rats in either diestrus or proestrus. At baseline, males and females showed striking dissimilarities in the dHPC proteome and phosphoproteome related to synaptic signaling and mitochondrial function—differences also strongly influenced by cycle stage in female rats. Notably, phosphoproteins enriched in PKA signaling emerged as being both significantly sex-dependent at baseline and also the primary target of ketamine-induced protein phosphorylation selectively in female rats, regardless of cycle stage. Reduced phosphoprotein abundance within this pathway was observed in males, suggesting bi-directional effects of low-dose ketamine between sexes. These findings present biological sex and hormonal milieu as critical modulators of ketamine’s rapid actions within this brain region and provide greater insight into potential translational and post-translational processes underlying sex- and hormone-dependent modulation of ketamine’s therapeutic effects.
“…Sex-dependent differences have been described in the neuronal structure, dendritic branching, as well as in the morphology and density of dendritic spines [2,29,42]. Sexrelated changes have been also investigated at the level of brain proteome [43][44][45][46]. Distler et al reported a profile of sex-specific synaptic proteins for different regions of the adult mouse brain, namely the hippocampus, cerebellum, prefrontal cortex, and striatum [43].…”
Section: Discussionmentioning
confidence: 99%
“…Distler et al reported a profile of sex-specific synaptic proteins for different regions of the adult mouse brain, namely the hippocampus, cerebellum, prefrontal cortex, and striatum [43]. It was also shown that the intersexual alterations in hippocampal protein expression pattern are related to those observed in behavioral tests [44]. Moreover, the differences in the proteomic profiling of the mouse hippocampus were shown to depend not only on the sex but also on the age of animals [45].…”
Although sex differences in the brain are prevalent, the knowledge about mechanisms underlying sex-related effects on normal and pathological brain functioning is rather poor. It is known that female and male brains differ in size and connectivity. Moreover, those differences are related to neuronal morphology, synaptic plasticity, and molecular signaling pathways. Among different processes assuring proper synapse functions are posttranslational modifications, and among them, S-palmitoylation (S-PALM) emerges as a crucial mechanism regulating synaptic integrity. Protein S-PALM is governed by a family of palmitoyl acyltransferases, also known as DHHC proteins. Here we focused on the sex-related functional importance of DHHC7 acyltransferase because of its S-PALM action over different synaptic proteins as well as sex steroid receptors. Using the mass spectrometry-based PANIMoni method, we identified sex-dependent differences in the S-PALM of synaptic proteins potentially involved in the regulation of membrane excitability and synaptic transmission as well as in the signaling of proteins involved in the structural plasticity of dendritic spines. To determine a mechanistic source for obtained sex-dependent changes in protein S-PALM, we analyzed synaptoneurosomes isolated from DHHC7-/- (DHHC7KO) female and male mice. Our data showed sex-dependent action of DHHC7 acyltransferase. Furthermore, we revealed that different S-PALM proteins control the same biological processes in male and female synapses.
“…Various studies have previously demonstrated sex-specific differences in protein expression [39][40][41] . Similar to findings in brain, urine, and apheresis platelet supernatant, we observed a clear protein signature associated with sex for mouse plasma, in both KO and control mice.…”
We proteotyped blood plasma from 30 mouse knockout strains and corresponding wild-type mice from the International Mouse Phenotyping Consortium. We used targeted proteomics with internal standards to quantify 375 proteins in 218 samples. Our results provide insights into the manifested effects of each gene knockout at the plasma proteome level. We first investigated possible contamination by erythrocytes during sample preparation and labeled, in one case, up to 11 differential proteins as erythrocyte originated. Second, we showed that differences in baseline protein abundance between female and male mice were evident in all mice, emphasizing the necessity to include both sexes in basic research, target discovery, and preclinical effect and safety studies. Next, we identified the protein signature of each gene knockout and performed functional analyses for all knockout strains. Further, to demonstrate how proteome analysis identifies the effect of gene deficiency beyond traditional phenotyping tests, we provide in-depth analysis of two strains, C8a−/− and Npc2+/−. The proteins encoded by these genes are well-characterized providing good validation of our method in homozygous and heterozygous knockout mice. Ig alpha chain C region, a poorly characterized protein, was among the differentiating proteins in C8a−/−. In Npc2+/− mice, where histopathology and traditional tests failed to differentiate heterozygous from wild-type mice, our data showed significant difference in various lysosomal storage disease-related proteins. Our results demonstrate how to combine absolute quantitative proteomics with mouse gene knockout strategies to systematically study the effect of protein absence. The approach used here for blood plasma is applicable to all tissue protein extracts.
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