Cortical Tissue Research Articles

STEM-06. DISTANT ORIGIN OF GLIOBLASTOMA RECURRENCE: NEURAL STEM CELLS IN THE SUBVENTRICULAR ZONE SERVE AS A SOURCE OF TUMOR RECONSTRUCTION AFTER PRIMARY RESECTION

Abstract The recurrence of glioblastoma (GBM) remains unavoidable. Neural stem cells (NSCs) in the subventricular zone (SVZ) are considered a treatment target due to their potential role as the cellular origin of GBM. However, it is not yet confirmed whether GBM recurrence also originates from these cells. We first conducted deep sequencing on paired patient samples, including primary tumors (pT), recurrent tumors (rT), and SVZ tissues. The sequencing results revealed that in 5 out of 9 patients, the rT evolved independently from the SVZ rather than directly from the pT. Based on this, we developed a mouse model to simulate the GBM recurrence process by transforming SVZ NSCs into GFP-labeled cells carrying cancer mutations via electroporation. Following the resection of the tdTomato-labeled pT, we observed that 57.1% of the rT consists of a mixture of GFP- and tdTomato-positive tumor cells. To study the behavior of NSCs, we improved the existing mouse model by removing cortical tissue to simulate the complete resection of the pT. Four weeks post-surgical resection, 64.7% of tumors reconstructed in the resection cavity (RC), driven by the migration of OPC lineage cells. Time-course RNA-seq results indicated that the CXCL12-CXCR4 pathway might be responsible for driving the migration of SVZ NSCs to the RC. Further deconvolution and fluorescence staining analysis confirmed that CXCL12 secreted by endothelial cells around the RC could drive CXCR4-positive NSCs to migrate to the area. Additionally, the CXCR4 antagonist AMD3100 significantly reduced tumor recurrence in mice and extended survival. RNA-seq results from both mouse and human paired tumor samples confirmed that the CXCL12-CXCR4 pathway was enriched in locally recurrent tumor specimens and was correlated with shorter patient survival. In summary, our study provides evidence that GBM recurrence originates from SVZ NSCs. Moreover, we identified the CXCL12-CXCR4 pathway as a potential therapeutic target for GBM recurrence.

TMET-19. REWIRING OF CORTICAL GLUCOSE METABOLISM FUELS HUMAN BRAIN CANCER GROWTH

Abstract The brain avidly consumes glucose to fuel neurophysiology. Cancers of the brain, such as glioblastoma (GBM), lose aspects of normal biology and gain the ability to proliferate and invade healthy tissue. How brain cancers rewire glucose utilization to fuel these processes is poorly understood. Here we perform infusions of 13C-labeled glucose into patients and mice with brain cancer to define the metabolic fates of glucose-derived carbon in tumor and cortex. By combining these measurements with quantitative metabolic flux analysis, we find that human cortex funnels glucose-derived carbons towards physiologic processes including TCA cycle oxidation and neurotransmitter synthesis. In contrast, brain cancers downregulate these physiologic processes, scavenge alternative carbon sources from the environment, and instead use glucose-derived carbons to produce molecules needed for proliferation and invasion. In particular, we find that cortical tissue produces its own glucose-derived serine, whereas gliomas predominantly consume serine from the environment. Targeting this metabolic rewiring in mice through dietary modulation selectively alters GBM metabolism and slows tumor growth. Combining dietary serine restriction with chemoradiation reduces brain tumor growth in mice, suggesting that such a dietary intervention could improve outcomes for patients with high grade glioma.

TMOD-16. ZUCLOPENTHIXOL REDUCES ACTIVITY-DEPENDENT GLIOBLASTOMA PROLIFERATION

Abstract A major challenge in modeling glioblastoma in the laboratory is the complex microenvironment in which tumors evolve in humans. The varied architecture and immune privilege of the brain limits the external validity of many experiments performed in modern cell biology laboratories. Organotypic human cortical slices present an opportunity to model glioblastoma and test the effect of drugs against glioma in ex-vivo human tissue. Cortical slice cultures maintain the cellular organization of the human brain, more closely approximating glioblastoma proliferation in patients. In this study, we test the effect zuclopenthixol, a repurposed antipsychotic inhibitor of glioblastoma-induced neuronal hyperexcitability, on the proliferation of glioblastoma cells in an organotypic human cortical slice culture. Primary patient-derived glioblastoma cultures were established, and human cortical tissues were emersed in oxygenated ACSF agarose gel before preparing 250 µm thick slices. Slices were either exogenously seeded with glioblastoma cells or stained for endogenous tumor infiltration. Slices with either endogenous or exogenous seeding were then treated with zuclopenthixol or regular media change and cultured for 10 days. Proliferation was measured with Ki67 staining and quantified via automated pixel summation using the Pillow library in Python. 0.1 µM zuclopenthixol treated slices had significantly lower proliferation index in both the endogenous tumor condition (0.04 vs 0.30, P < 0.05) and the exogenous seeding condition (0.0013 vs 0.028, P = 0.033). Reduced tissue integrity was observed beginning day 8 of culture, as tissue surrounding tumor seeding sites eroded. Here, we model glioblastoma proliferation in live human tissue and quantify the anti-proliferative effect of zuclopenthixol. We show that zuclopenthixol treatment significantly reduced the proliferation index. Our experimental model allowed the optimization of organotypic human cortical slice cultures for immunofluorescence studies and live-cell imaging.

Tanshinone IIA inhibits the apoptosis process of nerve cells by upshifting SIRT1 and FOXO3α protein and regulating anti- oxidative stress molecules and inflammatory factors in Cerebral Infarction Model

: Background as a prevalent cerebrovascular disorder, cerebral infarction (CI) has garnered extensive attention globally due to its high incidence and substantial fatality rate. Ischemia-reperfusion injury (IRI) exacerbates not only neuronal demise but also amplifies neural functional impairment. Tanshinone IIA (Tan IIA) has been identified to confer protection against IRI, yet the precise underlying mechanisms remain elusive. This work aimed to delve into the mechanistic role of Tan IIA in CI, with the goal of furnishing more distinct theoretical substantiation for its clinical application. Methods initially, a middle cerebral artery embolization model group (MCAO) model was established, followed by the categorization of rats into distinct groups based on different administration modes. Therapeutic effects were evaluated through indices including mortality rate, cerebral tissue water content, CI proportion, and neural functional scoring. Meanwhile, cellular apoptosis rates in hippocampal and cortical tissues, as well as levels of oxidative stress molecules (OSM), Sirtuin 1 (SIRT1), Forkhead box O3 (FOXO3α), and inflammatory factors, were examined to explore the mechanism of action. Results this work revealed that within varying doses of Tan IIA groups, as dosage escalated, mortality rate, cerebral edema severity, CI proportion, and neural functional scoring gradually diminished. Notably, the 35 mg/kg dose group exhibited the most significant reductions, with decreases of 74.9%, 12.7%, 47.5%, and 54% respectively. Cellular apoptosis rates in hippocampal and cortical tissues displayed a stepwise descending trend, with the 35 mg/kg dose group showcasing the largest reduction. SIRT1 and FOXO3α proteins exhibited a steady increase, with the 35 mg/kg dose group manifesting respective elevations of 87.9% and 65.5%, the highest among all groups. Antioxidant molecules glutathione (GSH) and superoxide dismutase (SOD) contents progressively increased, whereas malondialdehyde (MDA) and nitric oxide (NO) content decreased. The 35 mg/kg dose group recorded the highest increments of 49.1% and 58.1% for GSH and SOD content, while achieving the greatest reductions of 55.6% and 56.2% for MDA and NO content. Expression of inflammatory factors, namely tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and interleukin-6 (IL-6), gradually declined, with reductions of 42.1%, 32.2%, and 29.1% respectively in the 35 mg/kg dose group, exhibiting drastic differences (P < 0.05). Conclusion In conclusion, this research elucidates that Tan IIA improves cerebral edema and neural function by elevating intracellular expression of SIRT1 and FOXO3α proteins, modulating OSM and inflammatory factors. These findings yielded robust experimental support for the potential use of Tan IIA as a therapeutic agent for CI.

Research progress of tDCS in the treatment of ADHD.

TDCS is one of the most widely used non-invasive neuromodulation techniques, which changes the excitability of local cortical tissue by applying weak continuous direct current to the scalp, effectively improves the attention and concentration of ADHD children, and improves the impulse disorder of patients, but related research is still in its infancy. Based on a review of a large number of existing literatures and an analysis of the pathogenesis and principle of ADHD, this paper summarized the research on tDCS in the treatment of ADHD in recent years from the aspects of treatment mechanism, safety and stimulation parameters, and simply compared the application of tDCS with other non-traumatic neuromodulation techniques in the treatment of ADHD. The future development direction of this technology is further discussed.

Specific inhibition and disinhibition in the higher-order structure of a cortical connectome.

Neurons are thought to act as parts of assemblies with strong internal excitatory connectivity. Conversely, inhibition is often reduced to blanket inhibition with no targeting specificity. We analyzed the structure of excitation and inhibition in the MICrONS $mm^{3}$ dataset, an electron microscopic reconstruction of a piece of cortical tissue. We found that excitation was structured around a feed-forward flow in large non-random neuron motifs with a structure of information flow from a small number of sources to a larger number of potential targets. Inhibitory neurons connected with neurons in specific sequential positions of these motifs, implementing targeted and symmetrical competition between them. None of these trends are detectable in only pairwise connectivity, demonstrating that inhibition is structured by these large motifs. While descriptions of inhibition in cortical circuits range from non-specific blanket-inhibition to targeted, our results describe a form of targeting specificity existing in the higher-order structure of the connectome. These findings have important implications for the role of inhibition in learning and synaptic plasticity.

Hearing Function Moderates Age-Related Differences in Brain Morphometry in the HCP Aging Cohort.

There are well-established relationships between aging and neurodegenerative changes, and between aging and hearing loss. The goal of this study was to determine how structural brain aging is influenced by hearing loss. Human Connectome Project Aging data were analyzed, including T1-weighted Magnetic Resonance Imaging (MRI) and Words in noise (WIN) thresholds (n = 623). Freesurfer extracted gray and white matter volume, and cortical thickness, area, and curvature. Linear regression models targeted (1) interactions between age and WIN threshold and (2) correlations with WIN threshold adjusted for age, both corrected for false discovery rate (pFDR < 0.05). WIN threshold moderated age-related increase in volume in bilateral inferior lateral ventricles, with a higher threshold associated with increased age-related ventricle expansion. Age-related differences in the occipital cortex also increased with higher WIN thresholds. When controlling for age, high WIN threshold was correlated with reduced cortical thickness in Heschl's gyrus, calcarine sulcus, and other sensory regions, and reduced temporal lobe white matter. Older volunteers with poorer hearing and cognitive scores had the lowest volume in left parahippocampal white matter. These results suggest that better hearing is associated with reduced age-related differences in medial temporal lobe, while better hearing at any age is associated with greater cortical tissue in auditory and other sensory regions. Future longitudinal studies are needed to assess the causal nature of these relationships, but these results indicate interventions that preserve or protect hearing function may combat some neurodegenerative changes in aging.

Sex differences in contextual fear conditioning and extinction after acute and chronic nicotine treatment

BackgroundChronic cigarette smokers report withdrawal symptomology, including affective dysfunction and cognitive deficits. While there are studies demonstrating sex specific withdrawal symptomology in nicotine-dependent individuals, literature examining the underlying biological mediators of this is scant and not in complete agreement. Therefore, in this study, we evaluated the sex specific effects of nicotine and withdrawal on contextual fear memory, a hippocampally dependent aspect of cognition that is disrupted in nicotine withdrawal.MethodsMale and female B6/129F1 mice (8–13 weeks old) were used in all experiments. For the acute nicotine experiment, mice received intraperitoneal saline or nicotine (0.5 mg/kg) prior to contextual fear conditioning and test. For the chronic nicotine experiment, mice received nicotine (18 mg/kg/day) or saline for 11 days, then underwent contextual fear conditioning and test. Following the test, mice underwent minipump removal to elicit withdrawal or sham surgery, followed by the fear extinction assay. Bulk cortical tissue was used to determine nicotinic acetylcholine receptor levels via single point [3H]Epibatidine binding assay. Gene expression levels in the dorsal and ventral hippocampus were quantified via RT-PCR.ResultsWe found that female mice had a stronger expression of contextual fear memory than their male counterparts. Further, following acute nicotine treatment, male, but not female, subjects demonstrated augmented contextual fear memory expression. In contrast, no significant effects of chronic nicotine treatment on fear conditioning were observed in either sex. When examining extinction of fear learning, we observed that female mice withdrawn from nicotine displayed impaired extinction learning, but no effect was observed in males. Nicotine withdrawal caused similar suppression of fosb, cfos, and bdnf, our proxy for neuronal activation and plasticity changes, in the dorsal and ventral hippocampus of both sexes. Additionally, we found that ventral hippocampus erbb4 expression, a gene implicated in smoking cessation outcomes, was elevated in both sexes following nicotine withdrawal.ConclusionsDespite the similar impacts of nicotine withdrawal on gene expression levels, fosb, cfos, bdnf and erbb4 levels in the ventral hippocampus were predictive of delays in female extinction learning alone. This suggests sex specific dysfunction in hippocampal circuitry may contribute to female specific nicotine withdrawal induced deficits in extinction learning.

A Combination of Low Doses of Lithium and Valproate Improves Cognitive Outcomes after Mild Traumatic Brain Injury.

The prevalence of mild traumatic brain injury (mTBI) is high compared with moderate and severe TBI, comprising almost 80% of all brain injuries. mTBI activates a complex cascade of biochemical, molecular, structural, and pathological changes that can result in neurological and cognitive impairments. These impairments can manifest even in the absence of overt brain damage. Given the complexity of changes triggered by mTBI, a combination of drugs that target multiple TBI-activated cascades may be required to improve mTBI outcomes. It has been previously demonstrated that cotreatment with the U.S. Food and Drug Administration (FDA)-approved drugs lithium plus valproate (Li + VPA) for 3 weeks after a moderate-to-severe controlled cortical impact injury reduced cortical tissue loss and improved motor function. Since both lithium and valproate can exhibit toxicity at high doses, it would be beneficial to determine if this combination treatment is effective when administered at low doses and for a shorter duration, and if it can improve cognitive function, after a mild diffuse TBI. In the present study, we tested if the combination of low doses of lithium (1 mEq/kg or 0.5 mEq/kg) plus valproate (20 mg/kg) administered for 3 days after a mild fluid percussion injury can improve hippocampal-dependent learning and memory. Our data show that the combination of low-dose Li + VPA improved spatial learning and memory, effects not seen when either drug was administered alone. In addition, postinjury Li + VPA treatment improved recognition memory and sociability and reduced fear generalization. Postinjury Li + VPA also reduced the number of anti-ionized calcium binding adaptor molecule 1 (Iba1)-positive microglia counted using a convolutional neural network, indicating a reduction in neuroinflammation. These findings indicate that low-dose Li + VPA administered acutely after mTBI may have translational utility to reduce pathology and improve cognitive function.

Z-Scores for Assessing Ovarian Reserve in Young Patients Undergoing Fertility Preservation.

Women are born with a non-renewable pool of ovarian follicles, referred to as the ovarian reserve. This reserve consists of primordial follicles in the ovaries and can be affected by many factors, such as genetic and endocrine disorders, medical interventions, and endocrine disruptors. Fertility preservation is recommended when gonadotoxic treatments are necessary. The preferred options for women are oocyte and embryo cryopreservation. However, in very young, sexually immature patients, ovarian tissue cryopreservation is the only option. Knowing the follicular density of cryopreserved tissue samples is essential in fertility counseling for young patients. This protocol demonstrates the use of Z-scores for cortical follicle density as a tool to evaluate the quality of ovarian tissue in girls and young women aged 25 years and below who are undergoing fertility preservation. Follicle density in patient samples is compared to age-normalized reference standards, developed by Hassan et al. to estimate possible deviations from the standard. The follicle density is measured through histological quantification. For this, a small piece of ovarian cortical tissue (~2 mm x 2 mm x 2 mm) is fixed in either Bouin's or formaldehyde solution, embedded in paraffin, sectioned at 4 µm thickness, stained with hematoxylin and eosin, and digitized using a slide scanner. Follicular stages present in the cortex range from primordial to primary follicles. The cortical area was 1 mm from the surface epithelium on histological sections. Follicle density is calculated using a modified formula presented by Schmidt et al., and the Z-score is determined using the reference mean and standard deviation. The Z-score indicates how much the measured value deviates from the reference mean, determiningreduced (<-1.7 Z-score) ovarian reserve. With this method, follicle densities can be used as a valuable measure of ovarian reserve for young patients requiring fertility preservation.

In vitro growth of secondary follicles from cryopreserved-thawed ovarian cortex.

Can secondary follicles be obtained from cultured cryopreserved-thawed human ovarian cortical tissue? We obtained high-quality secondary follicles from cultured cryopreserved-thawed human ovarian cortical tissue from cis female donors (cOVA), but not from trans masculine donors (tOVA) in the same culture conditions. The in vitro growth of oocytes present in unilaminar follicles into metaphase II stage (MII) oocytes has been previously achieved starting from freshly obtained ovarian cortical tissue from adult cis female donors. This involved a multi-step culture protocol and the first step included the transition from unilaminar follicles to multilayered secondary follicles. Given that the ovarian cortex (from both cis female and trans masculine donors) used for fertility preservation is cryopreserved, it is crucial to investigate the potential of unilaminar follicles from cryopreserved-thawed ovarian cortex to grow in culture. Cryopreserved-thawed ovarian cortical tissue from adult trans masculine donors (n = 3) and adult cis female donors (n = 3) was used for in vitro culture following the first culture step described in two published culture protocols (7-8 days and 21 days) and compared to freshly isolated ovarian cortex from trans masculine donors (n = 3) and to ovarian cortex prior to culture. Ovarian cortical tissue was obtained from adult trans masculine donors undergoing gender-affirming surgery while using testosterone, and from adult cis female donors undergoing oophorectomy for fertility preservation purposes before chemotherapy. The ovarian cortex was fixed either prior (day 0) or after the culture period. Follicular survival, growth, and morphology were assessed through histology and immunofluorescence. We quantified the different stages of follicular development (primordial, primary, secondary, and atretic) after culture and observed an increase in the percentage of secondary follicles as well as an increase in COLIV deposition in the stromal compartment regardless of the culture media used. The quality of the secondary follicles obtained from cOVA was comparable to those prior to culture. However, in the same culture conditions, the secondary follicles from tOVA (fresh and cryo) showed low-quality secondary follicles, containing oocytes with small diameter, granulosa cells that expressed abnormal levels of KRT19 and steroidogenic-marker STAR and lacked ACTA2+ theca cells, when compared to tOVA secondary follicles prior to culture. The number of different donors used was limited. Our study revealed that cryopreserved-thawed cOVA can be used to generate high-quality secondary follicles after culture and those can now be further tested to evaluate their potential to generate functional MII oocytes that could be used in the clinic. However, using the same culture protocol on tOVA (fresh and cryo) did not yield high-quality secondary follicles, suggesting that either the testosterone treatment affects follicular quality or adapted culture protocols are necessary to obtain high-quality secondary follicles from tOVA. Importantly, caution must be taken when using tOVA to optimize folliculogenesis in vitro. This research was funded by the European Research Council Consolidator Grant OVOGROWTH (ERC-CoG-2016-725722 to J.S.D.V. and S.M.C.D.S.L.), the Novo Nordisk Foundation (reNEW NNF21CC0073729 to H.C., F.W., J.S.D.V., S.M.C.D.S.L.), and China Scholarship Council (CSC 202008320362 and CSC 202008450034 to H.C. and F.W.), respectively. The authors have no conflicts of interest to declare. N/A.

An analysis of RNA quality metrics in human brain tissue.

Human brain tissue studies have historically used a range of metrics to assess RNA quality. However, few large-scale cross-comparisons of pre-sequencing quality metrics with RNA-seq quality have been published. Here, we analyze how well metrics gathered before RNA sequencing (post-mortem interval (PMI) and RNA integrity number RIN) relate to analyses of RNA quality after sequencing (Percent of counts in Top Ten genes (PTT), 5' bias, and 3' bias) as well as with individual gene counts across the transcriptome. We conduct this analysis across four different human cortical brain tissue collections sequenced with varying library preparation protocols. PMI and RIN have a low inverse correlation, and both PMI and RIN show consistent and opposing correlations with PTT. Unlike PMI, RIN shows strong consistent correlations with measurements of 3' and 5' bias, and RIN also correlates with 3,933 genes across datasets, in comparison to 138 genes for PMI. Neuronal and immune response genes correlate positively and negatively with RIN respectively, suggesting that different gene sets have divergent relationships with RIN in brain tissue. In summary, these analyses suggest that conventional metrics of RNA quality have varying degrees of value, and that PMI has an overall minimal but reproducible effect on RNA quality.

Apoptosis is increased in cortical neurons of female Marfan Syndrome mice.

The study revealed that female mice with a FBN1 C1041G/+ mutation have more apoptotic neurons in sensory and motor cortical brain tissue compared to wildtype litter mates.

Transcriptomic analysis of rat prefrontal cortex following chronic stress induced by social isolation – Relevance to psychiatric and neurodevelopmental illness, and implications for treatment

Social isolation is an established risk factor for psychiatric illness, and became increasingly topical with the spread of SARS-CoV-2. We used RNA sequencing (RNA-Seq) to enable unbiased assessment of transcriptomic changes within the prefrontal cortex (PFC) of isolation-reared rats. To provide insight into the relevance of this manipulation for studying human illness, we compared differentially expressed genes (DEGs) and enriched biological functions against datasets involving post-mortem frontal cortical tissue from patients with psychiatric and neurodevelopmental illnesses. Sixteen male Sprague-Dawley rats were reared in groups of four or individually from weaning on postnatal day (PND) 22–24 until PFC tissue collection for RNA-Seq (PND64-66). We identified a total of 183 DEGs in isolates, of which 128 mirrored those in PFC tissue from patients with stress-related mental illnesses and/or neurodevelopmental conditions featuring social deficits. Seventy-one encode proteins classed as druggable by the gene-drug interaction database. Interestingly there are antagonists or inhibitors for the products of three of these up-regulated DEGs (Hrh3, Snca and Sod1) and agonists or activators for products of six of these down-regulated DEGs (Chrm4, Klf2, Lrrk2, Nr4a1, Nr4a3 and Prkca). Some have already undergone pre-clinical and clinical evaluation, and studies with the remainder may be warranted. Changes to Hrh3, Sod1, Chrm4, Lrrk2, Nr4a1 and Prkca were replicated in an independent cohort of sixteen male Sprague-Dawley rats via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Our findings support the continued use of post-weaning isolation rearing to investigate the neurobiology of stress-related disorders and evaluate therapeutic targets.

Simulated resections and responsive neurostimulator placement can optimize postoperative seizure outcomes when guided by fast ripple networks.

In medication-resistant epilepsy, the goal of epilepsy surgery is to make a patient seizure free with a resection/ablation that is as small as possible to minimize morbidity. The standard of care in planning the margins of epilepsy surgery involves electroclinical delineation of the seizure-onset zone and incorporation of neuroimaging findings from MRI, PET, single-photon emission CT and magnetoencephalography modalities. Resecting cortical tissue generating high-frequency oscillations has been investigated as a more efficacious alternative to targeting the seizure-onset zone. In this study, we used a support vector machine (SVM), with four distinct fast ripple (FR: 350-600 Hz on oscillations, 200-600 Hz on spikes) metrics as factors. These metrics included the FR resection ratio, a spatial FR network measure and two temporal FR network measures. The SVM was trained by the value of these four factors with respect to the actual resection boundaries and actual seizure-free labels of 18 patients with medically refractory focal epilepsy. Leave-one-out cross-validation of the trained SVM in this training set had an accuracy of 0.78. We next used a simulated iterative virtual resection targeting the FR sites that were of highest rate and showed most temporal autonomy. The trained SVM utilized the four virtual FR metrics to predict virtual seizure freedom. In all but one of the nine patients who were seizure free after surgery, we found that the virtual resections sufficient for virtual seizure freedom were larger in volume (P < 0.05). In nine patients who were not seizure free, a larger virtual resection made five virtually seizure free. We also examined 10 medically refractory focal epilepsy patients implanted with the responsive neurostimulator system and virtually targeted the responsive neurostimulator system stimulation contacts proximal to sites generating FR at highest rates to determine if the simulated value of the stimulated seizure-onset zone and stimulated FR metrics would trend towards those patients with a better seizure outcome. Our results suggest the following: (i) FR measures can accurately predict whether a resection, defined by the standard of care, will result in seizure freedom; (ii) utilizing FR alone for planning an efficacious surgery can be associated with larger resections; (iii) when FR metrics predict the standard-of-care resection will fail, amending the boundaries of the planned resection with certain FR-generating sites may improve outcome and (iv) more work is required to determine whether targeting responsive neurostimulator system stimulation contact proximal to FR generating sites will improve seizure outcome.

Nanocomposition of hydroxylapatite from cortical bone tissue

Nanocomposition of hydroxylapatite from cortical bone tissue

Traits associated with the conservation gradient are the strongest predictors of early‐stage fine root decomposition rates

Abstract Fine root traits span two independent axes of variation, the conservation and collaboration axes, which define the root economic space (RES). However, whether early‐stage fine root decomposition rates (quantified as proportion mass loss, i.e. pml) are more strongly related to collaboration or conservation traits remains unclear. We studied 63 tree species in New Zealand's temperate rain forest. We determined the phylogenetic signal in pml and fine root traits, conducted phylogenetic principal component analysis and used phylogenetic generalized least squares to determine which traits are most strongly related to pml. Root decomposition exhibited a high phylogenetic signal and was more strongly related to the conservation than the collaboration axis. Root tissue density (RTD) was negatively correlated and root nitrogen (RN) was positively correlated with pml. Root diameter was positively yet weakly correlated with pml, but specific root length was uncorrelated with pml. The lignin‐to‐N ratio and root cellulose were the strongest predictors of pml. Synthesis: Early‐stage fine root decomposition is most strongly driven by tissue quality traits, such as root nitrogen, tissue density and lignin‐to‐N ratio, which all align with the conservation axis of the root economics space. However, root diameter plays a weak yet undeniable role in early‐stage fine root decomposition. Some thick‐rooted species decomposed faster, possibly due to the higher quality cortical tissue. Thin‐rooted species decomposed slower, possibly because of their higher cellulose concentration that maintains the structural integrity of small diameter roots. Relationships between decomposition and other traits that align with the collaboration gradient deserve further study across the phylogeny of vascular plants.

Proinflammatory microglial activation impairs invitro cortical tissue repair via zinc-dependent ADAM17 cleavage of the CSF-1 receptor.

Infection and subsequent inflammatory processes negatively impact prognosis in individuals with traumatic brain injury (TBI). Tissue repair following TBI is tightly regulated by microglia, promoting or, importantly, preventing astrocyte-mediated repair processes, depending on the activation state of the neuroimmune cells. This study investigated the poorly understood mechanism linking proinflammatory microglia activation and astrocyte-mediated tissue repair using an invitro mechanical injury model in mixed cortical cultures of rat neurons and glia. We hypothesized that proinflammatory activation disrupts the microglial response to colony-stimulating factor 1 (CSF-1), which stimulates microglia migration and proliferation, both essential for astrocyte-mediated tissue repair. Following mechanical damage, cultures were treated with lipopolysaccharide (LPS) and interferon-gamma (IFNγ) to induce a proinflammatory state. Immunocytochemical and biochemical analyses were used to evaluate glial repair. Proinflammatory activation dramatically impeded wound closure, reducing microglial levels via upregulation of the zinc-dependent disintegrin and metalloprotease 17 (ADAM17), leading to the cleavage of the CSF-1 receptor (CSF-1R). Indeed, pharmacological inhibition of ADAM17 effectively promoted wound closure during inflammation. Moreover, zinc chelation prevented ADAM17-mediated cleavage of CSF-1R and induced the release of trophic factors, dramatically improving tissue recovery. Our findings strongly identify ADAM17 as a primary regulator of CSF-1R-mediated signaling and establish a mechanism defining the association between pro-inflammatory microglial activation and tissue repair following injury.

Examining epigenetic aging in the post-mortem brain in attention deficit hyperactivity disorder.

Mathematical algorithms known as "epigenetic clocks" use methylation values at a set of CpG sites to estimate the biological age of an individual in a tissue-specific manner. These clocks have demonstrated both acceleration and delays in epigenetic aging in multiple neuropsychiatric conditions, including schizophrenia and neurodevelopmental disorders such as autism spectrum disorder. However, no study to date has examined epigenetic aging in ADHD despite its status as one of the most prevalent neurodevelopmental conditions, with 1 in 9 children having ever received an ADHD diagnosis in the US. Only a handful of studies have examined epigenetic age in brain tissue from neurodevelopmental conditions, with none focused on ADHD, despite the obvious relevance to pathogenesis. Thus, here we asked if post-mortem brain tissue in those with lifetime histories of ADHD would show accelerated or delayed epigenetic age, as has been found for other neurodevelopmental conditions. We applied four different epigenetic clocks to estimate epigenetic age in individuals with ADHD and unaffected controls from cortical (anterior cingulate cortex, N = 55) and striatal (caudate, N = 56) post-mortem brain tissue, as well as peripheral blood (N = 84) and saliva (N = 112). After determining which epigenetic clock performed best in each tissue, we asked if ADHD was associated with altered biological aging in corticostriatal brain and peripheral tissues. We found that a range of epigenetic clocks accurately predicted chronological age in all tissues. We also found that a diagnosis of ADHD was not significantly associated with differential epigenetic aging, neither for the postmortem ACC or caudate, nor for peripheral tissues. These findings held when accounting for comorbid psychiatric diagnoses, substance use, and stimulant medication. Thus, in this study of epigenetic clocks in ADHD, we find no evidence of altered epigenetic aging in corticostriatal brain regions nor in peripheral tissue. We consider reasons for this unexpected finding, including the limited sampling of brain regions, the age range of individuals studied, and the possibility that processes that accelerate epigenetic age may be counteracted by the developmental delay posited in some models of ADHD.

7395 Developmental Programming: Adverse Effects Of Prenatal Exposure To A Real-Life Environmental Chemical Mixture Via Biosolids On Ovarian Folliculogenesis In Adult Sheep

Abstract Disclosure: Y. Zhou: None. K.M. Halloran: None. M. Bellingham: None. N.P. Evans: None. R.G. Lea: None. K.D. Sinclair: None. V. Padmanabhan: None. The ovarian capacity to provide fertilizable oocytes, regulate folliculogenesis as well as activate and progress primordial follicles into preovulatory follicles are key contributing factors to female fertility and reproductive aging. In sheep, as in humans, while genetics play a role in establishing the ovarian reserve during fetal development, developmental insults such as inappropriate exposure to native steroids or environmental chemicals (ECs) can adversely impact the establishment of the ovarian reserve and, additionally can affect folliculogenesis. Considering humans are exposed to multiple ECs simultaneously which could have additive, synergistic, or antagonistic effects, real-life EC exposure models are needed to assess risks posed by EC exposure. Offspring from sheep grazed on biosolids-treated pasture offers one such real-life exposure model. Studies with day 140 fetuses found maternal exposure to a real-life EC mixture via biosolids increased the proportion of unhealthy transitory follicles (Lea et al., Sci Rep. 2016;6:22279). The present study tested if biosolids exposure during fetal life would impact folliculogenesis, follicle activation and follicle atresia during their adult life. Ovaries were derived from adult EasyCare ewes (age 31.4 ± 0.5 months) whose mothers were grazed on biosolids-treated (BTP, n=10) or inorganic fertilizer-treated (Control, n=10) pastures from preconception through to birth. Ovarian morphometry was undertaken to assess the distribution and health status of follicles. Follicular atresia was evaluated via the expression of Caspase-3, an apoptosis marker. Data analysis utilized Student's t-test for normally distributed variables and Mann-Whitney U tests for non-parametric comparisons. There were no differences in the absolute counts or the percentages of follicle classes at all stages of folliculogenesis, the density of primordial follicles in cortical tissue, or the follicular activation rate. An increase in the percentage of unhealthy activated follicles (post-primordial) was noted in the BTP group (p = 0.014), predominantly in the transitory stage (p = 0.021). Consistent with this, a higher density of Caspase-3 positive primary follicles was observed in the BTP group (p = 0.033). These findings indicate the adverse impacts of fetal exposure to an EC mixture via maternal biosolid exposure on the survival of early-stage activated follicles in adult sheep. The lack of difference in ovarian reserve between the control and BTP groups suggests compensatory mechanisms may be in place to prevent premature depletion of the ovarian reserve. Whether EC mixture exposure via biosolids also has an adverse effect on the quality of the surviving activated follicles remains to be determined. Funding source: NIH R01 ES030374. Presentation: 6/3/2024