Sex steroid hormones such as 17β‐estradiol (estradiol) regulate neuronal function by binding to estrogen receptors (ERs), including ERα and GPER1, and through differential production via the enzyme ...aromatase. ERs and aromatase are expressed across the nervous system, including in the striatal brain regions. These regions, comprising the nucleus accumbens core, shell, and caudate–putamen, are instrumental for a wide‐range of functions and disorders that show sex differences in phenotype and/or incidence. Sex‐specific estrogen action is an integral component for generating these sex differences. A distinctive feature of the striatal regions is that in adulthood neurons exclusively express membrane but not nuclear ERs. This long‐standing finding dominates models of estrogen action in striatal regions. However, the developmental etiology of ER and aromatase cellular expression in female and male striatum is unknown. This omission in knowledge is important to address, as developmental stage influences cellular estrogenic mechanisms. Thus, ERα, GPER1, and aromatase cellular immunoreactivity was assessed in perinatal, prepubertal, and adult female and male rats. We tested the hypothesis that ERα, GPER1, and aromatase exhibits sex, region, and age‐specific differences, including nuclear expression. ERα exhibits nuclear expression in all three striatal regions before adulthood and disappears in a region‐ and sex‐specific time‐course. Cellular GPER1 expression decreases during development in a region‐ but not sex‐specific time‐course, resulting in extranuclear expression by adulthood. Somatic aromatase expression presents at prepuberty and increases by adulthood in a region‐ but not sex‐specific time‐course. These data indicate that developmental period exerts critical sex‐specific influences on striatal cellular estrogenic mechanisms.
Rat striatal regions express nuclear estrogen receptor α and GPER‐1 early in development, while aromatase expression increases with age. (a–f) Caudate–putamen micrographs depicting ERα positive cells or lack thereof females P3 (a), P20 (b), and adult (c); males P3 (d), P20 (e), and adult (f). Examples of ERα positive cells are marked by small white arrows.
•Glial cells demonstrate significant changes in frontotemporal degeneration (FTD).•Glial gene and protein expression were highly correlated in FTD.•Multi-omic approach provided novel insight into ...disease mechanisms of FTD.
To understand how glia may be altered in frontotemporal degeneration with tau pathology (FTD-tau), we used a NanoString glial profiling panel to measure 770 transcripts related to glial biology in human control (n = 8), Alzheimer's disease (AD) (n = 8), and FTD-tau (n = 8) dorsolateral prefrontal cortex. Compared to control, 43 genes were upregulated and 86 genes were downregulated in the FTD-tau samples. Only 3 genes were upregulated and 2 were downregulated in AD. Pathway analysis revealed many astrocyte-, microglia-, and oligodendrocyte-related pathway scores increased in FTD-tau, while neuron-related pathway scores decreased. We compared these results to a previously published proteomic dataset containing many of the same samples and found that the targeted panel approach obtained measurements for genes whose proteins were not measured in the proteomics. Our results point to the utility of multiomic approaches and marked dysregulation of glia in FTD-tau.
Medium spiny neurons (MSNs) in the nucleus accumbens have long been implicated in the neurobiological mechanisms that underlie numerous social and motivated behaviors as studied in rodents such as ...rats. Recently, the prairie vole has emerged as an important model animal for studying social behaviors, particularly regarding monogamy because of its ability to form pair bonds. However, to our knowledge, no study has assessed intrinsic vole MSN electrophysiological properties or tested how these properties vary with the strength of the pair bond between partnered voles. Here we performed whole cell patch-clamp recordings of MSNs in acute brain slices of the nucleus accumbens core (NAc) of adult male voles exhibiting strong and weak preferences for their respective partnered females. We first document vole MSN electrophysiological properties and provide comparison to rat MSNs. Vole MSNs demonstrated many canonical electrophysiological attributes shared across species but exhibited notable differences in excitability compared with rat MSNs. Second, we assessed male vole partner preference behavior and tested whether MSN electrophysiological properties varied with partner preference strength. Male vole partner preference showed extensive variability. We found that decreases in miniature excitatory postsynaptic current amplitude and the slope of the evoked action potential firing rate to depolarizing current injection weakly associated with increased preference for the partnered female. This suggests that excitatory synaptic strength and neuronal excitability may be decreased in MSNs in males exhibiting stronger preference for a partnered female. Overall, these data provide extensive documentation of MSN electrophysiological characteristics and their relationship to social behavior in the prairie vole. NEW & NOTEWORTHY This research represents the first assessment of prairie vole nucleus accumbens core medium spiny neuron intrinsic electrophysiological properties and probes the relationship between cellular excitability and social behavior.
Abstract Objective To define tauopathy‐associated changes in the human gray and white matter proteome. Method We applied tandem mass tagged labeling and mass spectrometry, consensus, and ratio ...weighted gene correlation network analysis (WGCNA) to gray and white matter sampled from postmortem human dorsolateral prefrontal cortex. The sampled tissues included control as well as Alzheimer's disease, corticobasal degeneration, progressive supranuclear palsy, frontotemporal degeneration with tau pathology, and chronic traumatic encephalopathy. Results Only eight proteins were unique to gray matter while six were unique to white matter. Comparison of the gray and white matter proteome revealed an enrichment of microglial proteins in the white matter. Consensus WGCNA sorted over 6700 protein isoforms into 46 consensus modules across the gray and white matter proteomic networks. Consensus network modules demonstrated unique and shared disease‐associated microglial and endothelial protein changes. Ratio WGCNA sorted over 6500 protein ratios (white:gray) into 33 modules. Modules associated with mitochondrial proteins and processes demonstrated higher white:gray ratios in diseased tissues relative to control, driven by mitochondrial protein downregulation in gray and upregulation in white. Interpretation The dataset is a valuable resource for understanding proteomic changes in human tauopathy gray and white matter. The identification of unique and shared disease‐associated changes across gray and white matter emphasizes the utility of examining both tissue types. Future studies of microglial, endothelial, and mitochondrial changes in white matter may provide novel insights into tauopathy‐associated changes in human brain.
The caudate-putamen is a striatal brain region essential for sensorimotor behaviors, habit learning, and other cognitive and premotor functions. The output and predominant neuron of the ...caudate-putamen is the medium spiny neuron (MSN). MSNs present discrete cellular subtypes that show differences in neurochemistry, dopamine receptor expression, efferent targets, gene expression, functional roles, and most importantly for this study, electrophysiological properties. MSN subtypes include the striatonigral and the striatopallidal groups. Most studies identify the striatopallidal MSN subtype as being more excitable than the striatonigral MSN subtype. However, there is some divergence between studies regarding the exact differences in electrophysiological properties. Furthermore, MSN subtype electrophysiological properties have not been reported disaggregated by biological sex. We addressed these questions using prepubertal male and female Drd1a-tdTomato line 6 BAC transgenic mice, an important transgenic line that has not yet received extensive electrophysiological analysis. We made acute caudate-putamen brain slices and assessed a robust battery of 16 relevant electrophysiological properties using whole-cell patch-clamp recording, including intrinsic membrane, action potential, and miniature EPSC (mEPSC) properties. We found that: (1) MSN subtypes exhibited multiple differential electrophysiological properties in both sexes, including rheobase, action potential threshold and width, input resistance in both the linear and rectified ranges, and mEPSC amplitude; (2) select electrophysiological properties showed interactions between MSN subtype and sex. These findings provide a comprehensive evaluation of mouse caudate-putamen MSN subtype electrophysiological properties across females and males, both confirming and extending previous studies.
Abstract
Background
Mutations in the progranulin gene (
GRN
) reduce levels of progranulin (PGRN) and granulins (GRNs) causing frontotemporal dementia (FTD), the most common form of early‐onset ...dementia. PGRN loss in neurons is associated with lysosome dysfunction resulting in diminished cathepsin protease activity. PGRN is also highly expressed in brain‐resident microglia and peripheral immune cells. Therefore, we asked if PGRN loss impacts immune cell profiles and communication in the gut‐brain axis during chronic systemic inflammation.
Methods
We measured lysosomal‐associated proteases in microglia and peripheral immune cells using probes for cathepsin D and pan‐cysteine cathepsins; performed multiplexed RNA & digital spatial protein profiling analyses, immunohistochemistry, and deep‐immunophenotyping by flow cytometry on brain, spleen, and peripheral blood of
Grn
KO and
Grn
‐suffficient mice aged 3‐30 months. Furthermore, we exposed mice to experimental colitis to interrogate alterations in the gut‐brain axis.
Results
Highest cathepsin D activity was found amongst Ly6C+, CD11b+ blood monocytes while pan‐cathepsin activity was highest in neutrophils and monocytes. In the spleen of aged
Grn
KO mice, T cell counts were reduced while Ly6C‐, CD68+ macrophages were increased compared to age‐matched
Grn
‐sufficient mice. In blood, aberrant T cell and monocyte activation markers in
Grn
KO mice were evident with minimal increases in inflammatory cytokines in plasma. Aged
Grn
KO mice exhibited decreased microglia (CD45int, CD11bhi) in the brain relative to
Grn
‐sufficient mice, with altered MHCII and CD68 expression. Additionally, CD4+ and CD8+ T cells were impacted in the brain of
Grn
KO mice compared to age‐matched
Grn
‐sufficient mice. PGRN loss was also associated with increased brain infiltration of activated peripheral monocytes and, interestingly, increased vulnerability to experimental colitis that was mitigated by loss of CCR2 function.
Conclusions
These novel findings suggest that PGRN plays key regulatory functions in innate and adaptive immune cell populations, in central‐peripheral immune cell crosstalk and traffic to the CNS, and in regulating susceptibility to immune challenges that disrupt the gut‐brain signaling axis. Analysis of peripheral immune cells and colonic tissue from patients with
Grn
mutations or SNPs is ongoing and may shed light on the mechanisms by which
GRN
haploinsufficiency causes FTD.
Background
Mutations in the progranulin gene (GRN) reduce levels of progranulin (PGRN) and granulins (GRNs) causing frontotemporal dementia (FTD), the most common form of early‐onset dementia. PGRN ...loss in neurons is associated with lysosome dysfunction resulting in diminished cathepsin protease activity. PGRN is also highly expressed in brain‐resident microglia and peripheral immune cells. Therefore, we asked if PGRN loss impacts immune cell profiles and communication in the gut‐brain axis during chronic systemic inflammation.
Methods
We measured lysosomal‐associated proteases in microglia and peripheral immune cells using probes for cathepsin D and pan‐cysteine cathepsins; performed multiplexed RNA & digital spatial protein profiling analyses, immunohistochemistry, and deep‐immunophenotyping by flow cytometry on brain, spleen, and peripheral blood of Grn KO and Grn‐suffficient mice aged 3‐30 months. Furthermore, we exposed mice to experimental colitis to interrogate alterations in the gut‐brain axis.
Results
Highest cathepsin D activity was found amongst Ly6C+, CD11b+ blood monocytes while pan‐cathepsin activity was highest in neutrophils and monocytes. In the spleen of aged Grn KO mice, T cell counts were reduced while Ly6C‐, CD68+ macrophages were increased compared to age‐matched Grn‐sufficient mice. In blood, aberrant T cell and monocyte activation markers in Grn KO mice were evident with minimal increases in inflammatory cytokines in plasma. Aged Grn KO mice exhibited decreased microglia (CD45int, CD11bhi) in the brain relative to Grn‐sufficient mice, with altered MHCII and CD68 expression. Additionally, CD4+ and CD8+ T cells were impacted in the brain of Grn KO mice compared to age‐matched Grn‐sufficient mice. PGRN loss was also associated with increased brain infiltration of activated peripheral monocytes and, interestingly, increased vulnerability to experimental colitis that was mitigated by loss of CCR2 function.
Conclusions
These novel findings suggest that PGRN plays key regulatory functions in innate and adaptive immune cell populations, in central‐peripheral immune cell crosstalk and traffic to the CNS, and in regulating susceptibility to immune challenges that disrupt the gut‐brain signaling axis. Analysis of peripheral immune cells and colonic tissue from patients with Grn mutations or SNPs is ongoing and may shed light on the mechanisms by which GRN haploinsufficiency causes FTD.
Abstract
Mammalian antibody switch regions (∼1500 bp) are composed of a series of closely neighboring G4-capable sequences. Whereas numerous structural and genome-wide analyses of roles for minimal ...G4s in transcriptional regulation have been reported, Long G4-capable regions (LG4s)—like those at antibody switch regions—remain virtually unexplored. Using a novel computational approach we have identified 301 LG4s in the human genome and find LG4s prone to mutation and significantly associated with chromosomal rearrangements in malignancy. Strikingly, 217 LG4s overlap annotated enhancers, and we find the promoters regulated by these enhancers markedly enriched in G4-capable sequences suggesting G4s facilitate promoter-enhancer interactions. Finally, and much to our surprise, we also find single-stranded loops of minimal G4s within individual LG4 loci are frequently highly complementary to one another with 178 LG4 loci averaging >35 internal loop:loop complements of >8 bp. As such, we hypothesized (then experimentally confirmed) that G4 loops within individual LG4 loci directly basepair with one another (similar to characterized stem–loop kissing interactions) forming a hitherto undescribed, higher-order, G4-based secondary structure we term a ‘G4 Kiss or G4K’. In conclusion, LG4s adopt novel, higher-order, composite G4 structures directly contributing to the inherent instability, regulatory capacity, and maintenance of these conspicuous genomic regions.
Background
Brain radiotherapy is used in the management of melanoma brain metastases (MBM) and can result in radionecrosis. Anti‐PD‐1 is active in the brain and may increase the risk of radionecrosis ...when combined with radiotherapy. We studied the incidence, associated factors and management of radionecrosis in longer‐term survivors with MBM treated with this combination.
Methods
Patients with MBM treated with radiotherapy and anti‐PD‐1 who survived >1 year were identified to determine radionecrosis incidence (Cohort A, n = 135). Cohort A plus additional radionecrosis cases were examined for factors associated with radionecrosis and management (Cohort B, n = 148).
Results
From Cohort A, 17% developed radionecrosis, with a cumulative incidence at 2 years of 18%. Using Cohort B, multivariable analysis confirmed an association between radionecrosis and elevated lactate dehydrogenase (p = 0.0496) and prior treatment with ipilimumab (p = 0.0319). Radionecrosis was diagnosed based on MRI (100%), symptoms (69%) and pathology (56%). Treatment included corticosteroids, bevacizumab and neurosurgery.
Conclusions
Radionecrosis is a significant toxicity in longer‐term melanoma survivors with MBM treated with anti‐PD‐1 and radiotherapy. Identification of those at risk of radionecrosis who may avoid radiotherapy is required.
To examine whether severe Gulf War illness (SGWI) case status was associated with longitudinal multimorbidity patterns.
Participants were users of the Veteran Health Administration Health Care System ...drawn from the Gulf War Era Cohort and Biorepository (
= 840). Longitudinal measures of multimorbidity were constructed using (1) electronic health records (Charlson Comorbidity Index; Elixhauser; and Veterans Affairs Frailty Index) from 10/1/1999 to 6/30/2023 and (2) self-reported medical conditions (Deficit Accumulation Index) since the war until the survey date. Accelerated failure time models examined SGWI case status as a predictor of time until threshold level of multimorbidity was reached, adjusted for age and sociodemographic and military characteristics.
Models, adjusted for covariates, revealed that (1) relative to the SWGI- group, the SGWI+ group was associated with an accelerated time for reaching each threshold and (2) the relationship between SGWI and each threshold was not moderated by age.
Findings suggest that veterans with SGWI experienced accelerated aging.
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