SynGAP is expressed in the murine suprachiasmatic nucleus and regulates circadian-gated locomotor activity and light-entrainment capacity.

The suprachiasmatic nucleus (SCN) of the hypothalamus functions as the master circadian clock. The phasing of the SCN oscillator is locked to the daily solar cycle, and an intracellular signaling cassette from the small GTPase Ras to the p44/42 mitogen-activated protein kinase (ERK/MAPK) pathway is central to this entrainment process. Here, we analyzed the expression and function of SynGAP-a GTPase-activating protein that serves as a negative regulator of Ras signaling-within the murine SCN. Using a combination of immunohistochemical and Western blotting approaches, we show that SynGAP is broadly expressed throughout the SCN. In addition, temporal profiling assays revealed that SynGAP expression is regulated over the circadian cycle, with peak expression occurring during the circadian night. Further, time-of-day-gated expression of SynGAP was not observed in clock arrhythmic BMAL1 null mice, indicating that the daily oscillation in SynGAP is driven by the inherent circadian timing mechanism. We also show that SynGAP phosphorylation at serine 1138-an event that has been found to modulate its functional efficacy-is regulated by clock time and is responsive to photic input. Finally, circadian phenotypic analysis of Syngap1 heterozygous mice revealed enhanced locomotor activity, increased sensitivity to light-evoked clock entrainment, and elevated levels of light-evoked MAPK activity, which is consistent with the role of SynGAP as a negative regulator of MAPK signaling. These findings reveal that SynGAP functions as a modulator of SCN clock entrainment, an effect that may contribute to sleep and circadian abnormalities observed in patients with SYNGAP1 gene mutations.

miR-132/212 is induced by stress and its dysregulation triggers anxiety-related behavior.

miR-132 and miR-212 are structurally-related microRNAs that are expressed from the same non-coding transcript. Accumulating evidence has shown that the dysregulation of these microRNAs contributes to aberrant neuronal plasticity and gene expression in the mammalian brain. Consistent with this, altered expression of miR-132 is associated with a number of affect-related psychiatric disorders. Here, we tested the functional contribution of the miR-132/212 locus to the development of stress-related and anxiety-like behaviors. Initially, we tested whether expression from the miR-132/212 locus is altered by stress-inducing paradigms. Using a 5-h acute-stress model, we show that both miR-132 and miR-212 are increased more than two-fold in the WT murine hippocampus and amygdala, whereas after a 15 day chronic-stress paradigm, expression of both miR-132 and miR-212 are upregulated more than two-fold within the amygdala but not in the hippocampus. Next, we used a tetracycline-inducible miR-132 overexpression mouse model and a miR-132/212 conditional knockout (cKO) mouse model to examine whether dysregulation of miR-132/212 expression alters basal anxiety-like behaviors. Interestingly, in both the miR-132 overexpression and cKO lines, significant increases in anxiety-like behaviors were detected. Importantly, suppression of transgenic miR-132 expression (via doxycycline administration) mitigated the anxiety-related behaviors. Further, expression of Sirt1 and Pten-two miR-132 target genes that have been implicated in the regulation of anxiety-were differentially regulated in the hippocampus and amygdala of miR-132/212 conditional knockout and miR-132 transgenic mice. Collectively, these data raise the prospect that miR-132 and miR-212 may play a key role in the modulation of stress responsivity and anxiety.

Data highlighting the expression of two miR-132/212 target genes-Sirt1 and Pten-after chronic stress.

The data presented here are related to our research article entitled "miR-132/212 is induced by stress and its dysregulation triggers anxiety-related behavior" (Aten et al., 2018). In this article, we utilize immunofluorescent techniques to examine the protein-level expression of two microRNA-132/212 target genes, Sirt1 and Pten, in miR-132 transgenic and miR-132/212 conditional knockout (cKO) mouse lines. Additionally, using immunohistochemistry, we detail the expression profile of Sirt1 and Pten in the hippocampus and amygdala of WT mice after a 15 day chronic restraint stress paradigm.

miR-132 couples the circadian clock to daily rhythms of neuronal plasticity and cognition.

The microRNA miR-132 serves as a key regulator of a wide range of plasticity-associated processes in the central nervous system. Interestingly, miR-132 expression has also been shown to be under the control of the circadian timing system. This finding, coupled with work showing that miR-132 is expressed in the hippocampus, where it influences neuronal morphology and memory, led us to test the idea that daily rhythms in miR-132 within the forebrain modulate cognition as a function of circadian time. Here, we show that hippocampal miR-132 expression is gated by the time-of-day, with peak levels occurring during the circadian night. Further, in miR-132 knockout mice and in transgenic mice, where miR-132 is constitutively expressed under the control of the tetracycline regulator system, we found that time-of-day dependent memory recall (as assessed via novel object location and contextual fear conditioning paradigms) was suppressed. Given that miRNAs exert their functional effects via the suppression of target gene expression, we examined the effects that transgenic miR-132 manipulations have on MeCP2 and Sirt1-two miR-132 targets that are associated with neuronal plasticity and cognition. In mice where miR-132 was either knocked out, or transgenically expressed, rhythmic expression of MeCP2 and Sirt1 was suppressed. Taken together, these results raise the prospect that miR-132 serves as a key route through which the circadian timing system imparts a daily rhythm on cognitive capacity.

Reduced marker of vascularization in the anterior hippocampus in a female monkey model of depression.

Depression is a common and debilitating mood disorder that impacts women more often than men. The mechanisms that result in depressive behaviors are not fully understood; however, the hippocampus has been noted as a key structure in the pathophysiology of depression. In addition to neural implications of depression, the cardiovascular system is impacted. Although not as commonly considered, the cerebrovasculature is critical to brain function, impacted by environmental stimuli, and is capable of altering neural function and thereby behavior. In the current study, we assessed the relationship between depressive behavior and a marker of vascularization of the hippocampus in adult female cynomolgus macaques (Macaca fascicularis). Similar to previously noted impacts on neuropil and glia, the depressed phenotype predicts a reduction in a marker of vascular length in the anterior hippocampus. These data reinforce the growing recognition of the effects of depression on vasculature and support further consideration of vascular endpoints in studies aimed at the elucidation of the mechanisms underlying depression.

Human papillomavirus DNA is rarely detected in colorectal carcinomas and not associated with microsatellite instability: the Seattle colon cancer family registry.

BACKGROUND: Persistent infection with oncogenic human papillomavirus (HPV) types-16 and -18 is an established cause of cervical and other cancers. Some studies report detection of oncogenic HPV DNA in colorectal carcinomas, with prevalence estimates as high as 84%. However, other studies report detecting no HPV DNA in colorectal tumors. METHODS: To evaluate the prevalence of HPV in colorectal cancer subsets, we conducted a case-case comparison study. This study included 555 cases of incident colorectal cancer from the Seattle Colon Cancer Family Registry (CCFR), ages 20 to 74 years and diagnosed between 1998 and 2002. Standardized interviews were used to elicit demographics and risk factor data. Tumor DNA was assayed for HPV-16 and -18 DNA using real-time PCR. Microsatellite instability (MSI) status was assessed using a standard 10-marker panel and confirmed with immunohistochemical staining. Prevalence estimates were calculated for the overall sample, and stratified by patient and tumor characteristics. Fisher exact test was used to compare prevalence between strata. RESULTS: HPV-16 DNA was detected in 2% of colorectal tumors, but no HPV-18 DNA was detected. HPV-16 prevalence did not vary between cases according to sex, age, race, smoking-status, or MSI-status (P > 0.05). HPV-16 prevalence in rectal carcinomas was 5% compared with 1% in colon carcinomas (P = 0.03). CONCLUSIONS: Among a large sample of colorectal carcinomas, prevalence of HPV-16 and -18 was very low. Prior studies detecting high HPV prevalence in colorectal carcinomas are likely the result of contamination from the anal canal or clinical processing. IMPACT: HPV is unlikely to play a large role in colorectal carcinogenesis.