Cortical Tissue Research Articles

Activation of GPER-1 Attenuates Traumatic Brain Injury-Induced Neurological Impairments in Mice.

This study aimed to investigate the effects of G1-activated G protein-coupled estrogen receptor 1 (GPER1) on neurological impairments and neuroinflammation in traumatic brain injury (TBI) mice. The controlled cortical impingement (CCI) method was used to establish the TBI model. The mice were subjected to ovariectomy (OVX) for two weeks prior to modeling. GPER1 agonist G1 was administered by intracerebroventricular injection. Brain tissue water content was detected by wet/dry method, and blood-brain barrier damage was detected by Evans blue extravasation. The neurological impairments in mice were evaluated by open field test, Y-maze test, nest-building test, object location memory test and novel object recognition test. Ionized calcium-binding adapter molecule 1 (Iba1) staining was used to indicate the activation of microglia. Expression of M1/M2-type microglia markers and inflammatory factors were evaluated by ELISA and qRT-PCR. The G1 administration significantly reduced cerebral edema and Evans blue extravasation at injury ipsilateral cortex and basal ganglia in TBI mice. Activation of GPER1 by G1 improved the anxiety behavior and the cognitive dysfunction of mice induced by TBI. G1 administration significantly decreased Iba1-positive staining cells and the mRNA levels of CD86, macrophage cationic peptide 1 (Mcp-1), nitric oxide synthase 2 (Nos2), interleukin 1 beta (IL-1β), and macrophage inflammatory protein-2 (MIP-2), while increased the mRNA levels of interleukin 10 (IL-10), arginase1 (Arg-1) and CD206. Activation of GPER1 through G1 administration has the potential to ameliorate cognitive dysfunction induced by TBI in mice. It may also inhibit the activation of M1 microglia in cortical tissue resulting from TBI, while promoting the activation of M2 microglia and contributing to the regulation of inflammatory responses.

Gene knockout of RNA binding motif 5 in the brain alters RIMS2 protein homeostasis in the cerebellum and Hippocampus and exacerbates behavioral deficits after a TBI in mice

RNA binding motif 5 (RBM5) is a tumor suppressor in cancer but its role in the brain is unclear. We used conditional gene knockout (KO) mice to test if RBM5 inhibition in the brain affects chronic cortical brain tissue survival or function after a controlled cortical impact (CCI) traumatic brain injury (TBI). RBM5 KO decreased baseline contralateral hemispheric volume (p < 0.0001) and exacerbated ipsilateral tissue loss at 21 d after CCI in male mice vs. wild type (WT) (p = 0.0019). CCI injury, but not RBM5 KO, impaired beam balance performance (0-5d post-injury) and swim speed on the Morris Water Maze (MWM) (19-20d) (p < 0.0001). RBM5 KO was associated with mild learning impairment in female mice (p = 0.0426), reflected as a modest increase in escape latency early in training (14-18d post-injury). However, KO did not affect spatial memory at 19d post-injury in male or in female mice but it was impaired by CCI in females (p = 0.0061). RBM5 KO was associated with impaired visual function in male mice on the visible platform test at 20d post-injury (p = 0.0256). To explore signaling disturbances in KOs related to behavior, we first cross-referenced known brain-specific RBM5-regulated gene targets with genes in the curated RetNet database that impact vision. We then performed a secondary literature search on RBM5-regulated genes with a putative role in hippocampal function. Regulating synaptic membrane exocytosis 2 (RIMS) 2 was identified as a gene of interest because it regulates both vision and hippocampal function. Immunoprecipitation and western blot confirmed protein expression of a novel ~170 kDa RIMS2 variant in the cerebellum, and in the hippocampus, it was significantly increased in KO vs WT (p < 0.0001), and in a sex-dependent manner (p = 0.0390). Furthermore, male KOs had decreased total canonical RIMS2 levels in the cerebellum (p = 0.0027) and hippocampus (p < 0.0001), whereas female KOs had increased total RIMS1 levels in the cerebellum (p = 0.0389). In summary, RBM5 modulates brain function in mammals. Future work is needed to test if RBM5 dependent regulation of RIMS2 splicing effects vision and cognition, and to verify potential sex differences on behavior in a larger cohort of mice.

Uncovering the hidden hosts: Identifying inoculum reservoirs for Phytophthora pseudosyringae in Nothofagus forests in Chile

AbstractMortality of Nothofagus trees in native forests in Chile has been observed for more than 30 years. Phytophthora pseudosyringae was identified as the causal agent of partial defoliation and bleeding cankers on Nothofagus obliqua and N. alpina. Nevertheless, to improve the conservation of natural resources it is crucial to determine potential native hosts that may act as inoculum reservoirs. Two N. obliqua stands were visited and all native plant species with symptoms resembling those caused by Phytophthora spp. were examined. Seven isolates from cortical and foliar tissues were isolated and subsequentially identified as P. pseudosyringae. Pathogenicity tests were carried out on eight species from a native forest. P. pseudosyringae caused cankers in N. obliqua, N. dombeyi and Persea lingue. Under natural conditions, no symptoms were detected on leaves of Cryptocarya alba, N. dombeyi, N. obliqua or Peumus boldus, but lesions were formed in inoculation assays under a controlled environment, suggesting that these species may act as hosts. Leaf necrosis in P. lingue was observed in both natural and controlled conditions. P. pseudosyringae can sporulate on lesions of C. alba, N. dombeyi and N. obliqua leaves. In Sophora macrocarpa, sporulation was observed both on asymptomatic tissues and on lesions. The frequent association of S. macrocarpa in the understorey of Nothofagus spp. strengthens the putative role of S. macrocarpa as an inoculum reservoir for epidemic events in Nothofagus. This is the first study carried out in the Southern Hemisphere on the life cycle of P. pseudosyringae in native Nothofagus forests.

MR1/MAIT Cell Axis Impacts Innate Immunity and Synaptic Proteins in 5XFAD Mice

Background:&#x0D; Amyloid beta (Aβ)-induced synaptic dysfunction and inflammation are features of Alzheimer’s disease (AD). One contributor to inflammation is mucosal-associated invariant T (MAIT) cells, an innate T cell that recognizes antigens presented by the MR1 molecule. Previously, we found increased MR1 expression in microglia near plaques and the loss of MR1/MAIT cell axis slowed the progression of Aβ pathology. This study aimed to determine contributions of the MR1/MAIT cell axis to immunity and synaptic proteins in the 5XFAD AD model mouse.&#x0D; Methods:&#x0D; We crossed 5XFAD mice with MR1-deficient mice (which lack MR1 and MAIT cells). At 2-, 4-, 6-, and 8-months of age, hippocampal and cortical brain tissue from wild-type, MR1KO, 5XFAD, and 5XFAD/MR1KO mice were analyzed by Western blot. Protein levels were analyzed with antibodies against GFAP (astrocytes), complement C3, and postsynaptic density protein (PSD)95. Additionally, Novel Object Recognition, Open Field, and Barnes Maze behavioral tests were performed in the 5XFAD mice to measure memory deficits.&#x0D; Results:&#x0D; Region-specific results were obtained for the hippocampus and cortex. The expression levels of PSD95 and C3 were significantly upregulated in the hippocampus of 5XFAD/MR1KO compared to 5XFAD mice at 6-8 months of age; in the cortex, GFAP levels were also significantly increased in 5XFAD/MR1KO mice. Finally, compared to wildtype C57BL/6 mice, 5XFAD mice showed memory deficits.&#x0D; Conclusions and Potential Impact:&#x0D; Approximately 6.7 million Americans are living with AD. This number is expected to double by 2050. Without any currently demonstrated therapy against AD, there is a need for therapeutic target(s) as part of novel treatment paradigms. Our results demonstrate an impact of the MR1/MAIT cell axis on postsynaptic proteins and consequent AD pathology. Thus, understanding the contribution of this axis could help reveal the role of innate immunity in AD and potentially serve as a future therapeutic target in AD patients.

Maximum likelihood estimation of renal transporter ontogeny profiles for pediatric PBPK modeling.

Optimal treatment of infants with many renally cleared drugs must account for maturational differences in renal transporter (RT) activity. Pediatric physiologically-based pharmacokinetic (PBPK) models may incorporate RT activity, but this requires ontogeny profiles for RT activity in children, especially neonates, to predict drug disposition. Therefore, RT expression measurements from human kidney postmortem cortical tissue samples were normalized to represent a fraction of mature RT activity. Using these data, maximum likelihood estimated the distributions of RT activity across the pediatric age spectrum, including preterm and term neonates. PBPK models of four RT substrates (acyclovir, ciprofloxacin, furosemide, and meropenem) were evaluated with and without ontogeny profiles using average fold error (AFE), absolute average fold error (AAFE), and proportion of observations within the 5-95% prediction interval. Novel maximum likelihood profiles estimated ontogeny distributions for the following RT: OAT1, OAT3, OCT2, P-gp, URAT1, BCRP, MATE1, MRP2, MRP4, and MATE-2 K. Profiles for OAT3, P-gp, and MATE1 improved infant furosemide and neonate meropenem PBPK model AFE from 0.08 to 0.70 and 0.53 to 1.34 and model AAFE from 12.08 to 1.44 and 2.09 to 1.36, respectively, and improved the percent of data within the 5-95% prediction interval from 48% to 98% for neonatal ciprofloxacin simulations, respectively. Even after accounting for other critical population-specific maturational differences, novel RT ontogeny profiles substantially improved neonatal PBPK model performance, providing validated estimates of maturational differences in RT activity for optimal dosing in children.

Increased cysteinyl-tRNA synthetase drives neuroinflammation in Alzheimer’s disease

BackgroundMicroglia-mediated neuroinflammation in Alzheimer’s disease (AD) is not only a response to pathophysiological events, but also plays a causative role in neurodegeneration. Cytoplasmic cysteinyl-tRNA synthetase (CARS) is considered to be a stimulant for immune responses to diseases; however, it remains unknown whether CARS is involved in the pathogenesis of AD.MethodsPostmortem human temporal cortical tissues at different Braak stages and AD patient-derived serum samples were used to investigate the changes of CARS levels in AD by immunocytochemical staining, real-time PCR, western blotting and ELISA. After that, C57BL/6J and APP/PS1 transgenic mice and BV-2 cell line were used to explore the role of CARS protein in memory and neuroinflammation, as well as the underlying mechanisms. Finally, the associations of morphological features among CARS protein, microglia and dense-core plaques were examined by immunocytochemical staining.ResultsA positive correlation was found between aging and the intensity of CARS immunoreactivity in the temporal cortex. Both protein and mRNA levels of CARS were increased in the temporal cortex of AD patients. Immunocytochemical staining revealed increased CARS immunoreactivity in neurons of the temporal cortex in AD patients. Moreover, overexpression of CARS in hippocampal neurons induced and aggravated cognitive dysfunction in C57BL/6J and APP/PS1 mice, respectively, accompanied by activation of microglia and the TLR2/MyD88 signaling pathway as well as upregulation of proinflammatory cytokines. In vitro experiments showed that CARS treatment facilitated the production of proinflammatory cytokines and the activation of the TLR2/MyD88 signaling pathway of BV-2 cells. The accumulation of CARS protein occurred within dense-core Aβ plaques accompanied by recruitment of ameboid microglia. Significant upregulation of TLR2/MyD88 proteins was also observed in the temporal cortex of AD.ConclusionsThe findings suggest that the neuronal CARS drives neuroinflammation and induces memory deficits, which might be involved in the pathogenesis of AD.

SOX2 and SOX9 Expression in Developing Postnatal Opossum (Monodelphis domestica) Cortex.

(1) Background: Central nervous system (CNS) development is characterized by dynamic changes in cell proliferation and differentiation. Key regulators of these transitions are the transcription factors such as SOX2 and SOX9. SOX2 is involved in the maintenance of progenitor cell state and neural stem cell multipotency, while SOX9, expressed in neurogenic niches, plays an important role in neuron/glia switch with predominant expression in astrocytes in the adult brain. (2) Methods: To validate SOX2 and SOX9 expression patterns in developing opossum (Monodelphis domestica) cortex, we used immunohistochemistry (IHC) and the isotropic fractionator method on fixed cortical tissue from comparable postnatal ages, as well as dissociated primary neuronal cultures. (3) Results: Neurons positive for both neuronal (TUJ1 or NeuN) and stem cell (SOX2) markers were identified, and their presence was confirmed with all methods and postnatal age groups (P4-6, P6-18, and P30) analyzed. SOX9 showed exclusive staining in non-neuronal cells, and it was coexpressed with SOX2. (4) Conclusions: The persistence of SOX2 expression in developing cortical neurons of M. domestica during the first postnatal month implies the functional role of SOX2 during neuronal differentiation and maturation, which was not previously reported in opossums.

Cortical matrix remodeling as a hallmark of relapsing–remitting neuroinflammation in MR elastography and quantitative MRI

Multiple sclerosis (MS) is a chronic neuroinflammatory disease that involves both white and gray matter. Although gray matter damage is a major contributor to disability in MS patients, conventional clinical magnetic resonance imaging (MRI) fails to accurately detect gray matter pathology and establish a clear correlation with clinical symptoms. Using magnetic resonance elastography (MRE), we previously reported global brain softening in MS and experimental autoimmune encephalomyelitis (EAE). However, it needs to be established if changes of the spatiotemporal patterns of brain tissue mechanics constitute a marker of neuroinflammation. Here, we use advanced multifrequency MRE with tomoelastography postprocessing to investigate longitudinal and regional inflammation-induced tissue changes in EAE and in a small group of MS patients. Surprisingly, we found reversible softening in synchrony with the EAE disease course predominantly in the cortex of the mouse brain. This cortical softening was associated neither with a shift of tissue water compartments as quantified by T2-mapping and diffusion-weighted MRI, nor with leukocyte infiltration as seen by histopathology. Instead, cortical softening correlated with transient structural remodeling of perineuronal nets (PNNs), which involved abnormal chondroitin sulfate expression and microgliosis. These mechanisms also appear to be critical in humans with MS, where tomoelastography for the first time demonstrated marked cortical softening. Taken together, our study shows that neuroinflammation (i) critically affects the integrity of PNNs in cortical brain tissue, in a reversible process that correlates with disease disability in EAE, (ii) reduces the mechanical integrity of brain tissue rather than leading to water accumulation, and (iii) shows similar spatial patterns in humans and mice. These results raise the prospect of leveraging MRE and quantitative MRI for MS staging and monitoring treatment in affected patients.

Bilateral Renal Cortical Necrosis and Reversible Cerebral Vasoconstriction Syndrome in a Case of Severe Postpartum Haemorrhage

Bilateral Renal Cortical Necrosis (BRCN) is a rare but serious condition characterised by the ischaemic necrosis of both kidneys’ cortical tissues. Concurrently, Reversible Cerebral Vasoconstriction Syndrome (RCVS) manifests as a transient constriction of cerebral blood vessels. The fusion of these two rare entities within the context of severe Postpartum Haemorrhage (PPH) poses a unique diagnostic and therapeutic dilemma for healthcare practitioners. This case study documents the intricate and severe complications experienced by a 32-year-old primiparous woman following abruptio placenta with Intrauterine Foetal Death (IUFD). The patient presented with massive vaginal bleeding, leading to an emergency Lower Segment Caesarean Section (LSCS) where bilateral uterine artery ligation and bilateral internal iliac artery ligation were performed to control haemorrhage. Despite initial interventions, the patient’s condition deteriorated, leading to signs of shock, haemoperitoneum, sepsis, Acute Kidney Injury (AKI), and cerebral complications. The medical journey unfolded with an urgent re-laparotomy, draining haemoperitoneum and conducting a subtotal hysterectomy. This case highlights the critical importance of a multidisciplinary approach involving obstetrics, nephrology, and intensive care, in managing such complex postpartum complications. Vigilant monitoring, collaborative decision-making, and meticulous postoperative care played pivotal roles. The successful outcome was attributed to early recognition, aggressive supportive measures, and timely interventions, including haemodialysis. The challenges faced underscore the need for accessible obstetric care, awareness about antenatal complications, and community-focused initiatives. Further research is warranted to unravel the intricate connections between PPH, RCVS, and associated complications, enhancing our understanding and improving patient outcomes in similar critical cases.

Pomalidomide Improves Motor Behavioral Deficits and Protects Cerebral Cortex and Striatum Against Neurodegeneration Through a Reduction of Oxidative/Nitrosative Damages and Neuroinflammation After Traumatic Brain Injury.

Neuronal damage resulting from traumatic brain injury (TBI) causes disruption of neuronal projections and neurotransmission that contribute to behavioral deficits. Cellular generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is an early event following TBI. ROS often damage DNA, lipids, proteins, and carbohydrates while RNS attack proteins. The products of lipid peroxidation 4-hydroxynonenal (4-HNE) and protein nitration 3-nitrotyrosine (3-NT) are often used as indicators of oxidative and nitrosative damages, respectively. Increasing evidence has shown that striatum is vulnerable to damage from TBI with a disturbed dopamine neurotransmission. TBI results in neurodegeneration, oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy in the striatum and contribute to motor or behavioral deficits. Pomalidomide (Pom) is a Food and Drug Administration (FDA)-approved immunomodulatory drug clinically used in treating multiple myeloma. We previously showed that Pom reduces neuroinflammation and neuronal death induced by TBI in rat cerebral cortex. Here, we further compared the effects of Pom in cortex and striatum focusing on neurodegeneration, oxidative and nitrosative damages, as well as neuroinflammation following TBI. Sprague-Dawley rats subjected to a controlled cortical impact were used as the animal model of TBI. Systemic administration of Pom (0.5 mg/kg, intravenous [i.v.]) at 5 h post-injury alleviated motor behavioral deficits, contusion volume at 24 h after TBI. Pom alleviated TBI-induced neurodegeneration stained by Fluoro-Jade C in both cortex and striatum. Notably, Pom treatment reduces oxidative and nitrosative damages in cortex and striatum and is more efficacious in striatum (93% reduction in 4-HNE-positive and 84% reduction in 3-NT-positive neurons) than in cerebral cortex (42% reduction in 4-HNE-positive and 55% reduction in 3-NT-positive neurons). In addition, Pom attenuated microgliosis, astrogliosis, and elevations of proinflammatory cytokines in cortical and striatal tissue. We conclude that Pom may contribute to improved motor behavioral outcomes after TBI through targeting oxidative/nitrosative damages and neuroinflammation.

Brain Tissue Oxygen Dynamics Under Localised Hypoxia in the Awake State and the Physical Neuroprotective Effects of General Anaesthesia.

Brain health directly depends on maintaining a level of tissue oxygen that is high enough to avoid global hypoxia and local brain ischaemia. It is well documented that general anaesthesia has an anti-hypoxic neuroprotective effect. Previous studies of this effect primarily assessed the biochemical actions of anaesthetics. Physical actions were not well studied because the quantification of oxygen dynamics has only recently been described. Based on known oxygen, blood, and neuronal measurements, under various anaesthesia protocols and in the awake state, we mathematically analysed physical anaesthesia effects on oxygen distribution for localised hypoxia. From this, we built a universal equation of oxygen dynamics which can be applied to both animal and human subjects in awake and anaesthetised states, under normoxia, hyperoxia, and hypoxia. Using this equation, we determined that a proper anaesthesia protocol can protect up to 167 mm3 of local hypoxic cortical brain tissue via oxygen diffusion from healthy neighbouring areas.

Histone deacetylase 3-specific inhibitor RGFP966 attenuates oxidative stress and inflammation after traumatic brain injury by activating the Nrf2 pathway.

Oxidative stress (OS) and inflammatory reactions play pivotal roles in secondary brain injury after traumatic brain injury (TBI). Histone deacetylase 3 (HDAC3) controls the acetylation of histones and non-histones, which has a significant impact on the central nervous system's reaction to damage. This research determined the implications of RGFP966, a new and specific inhibitor of HDAC3, for the antioxidant (AO) systems mediated by nuclear factor erythroid2-related factor 2 (Nrf2) and the Nod-like receptor protein 3 (NLRP3) inflammasome in TBI. The study also studied the underlying mechanisms of RGFP966's actions. Our objective was to examine the impacts and underlying RGFP966 mechanisms in TBI. In vitro, a rat cortical neuron OS model was induced by H2O2, followed by the addition of RGFP966 to the culture medium. Neurons were collected after 24h for western blot (WB), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and 2'-7'-dichlorodihydrofluorescein diacetate staining. In vivo, RGFP966 (10mg/kg) was administered post-TBI. Brain tissue water content and modified neurological severity scores were assessed 72h post-injury. Cortical tissues surrounding the focal injury were subjected to western blot, TUNEL staining, Nissl staining and immunofluorescence/immunohistochemistry staining, and malondialdehyde level, hindered glutathione content and superoxide dismutase activity were measured. Serum was collected for the enzyme-linked immunosorbent assay. Nrf2-specific shRNA lentivirus was injected into the lateral ventricle of rats for 7days, and cerebral cortex tissue was analyzed by WB and real-time polymerase chain reaction. During in vitro and in vivo experiments, RGFP966 suppressed HDAC3 expression, promoted Nrf2 nuclear translocation, activated downstream AO enzymes, mitigated excessive reactive oxygen species production and alleviated nerve cell apoptosis. RGFP966 effectively reduced brain edema and histological damage and enhanced neurological and cognitive function in rats with TBI. RGFP966 markedly inhibited NLRP3 inflammasome activation mediated by high-mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4). Nrf2 knockdown in TBI rats attenuated the AO and anti-inflammatory, neuroprotective impacts of RGFP966. Overall, our findings demonstrate that RGFP966 can mitigate the first brain damage and neurological impairments in TBI. The underlying mechanism involves triggering the Nrf2-mediated AO system and negatively regulating the HMGB1/TLR4-mediated NLRP3 inflammasome pathway.

Hyperbaric oxygen therapy alleviates intestinal dysfunction following traumatic brain injury via m6A regulation.

Hyperbaric oxygen (HBO) therapy can attenuate neurological impairment after traumatic brain injury (TBI) and alleviate intestinal dysfunction. However, the role and mechanism of HBO therapy in intestinal dysfunction following TBI remain unclear. Herein, by establishing a mouse model of controlled cortical impact (CCI), we found that HBO therapy reduced histopathological lesions and decreased the levels of inflammatory and oedema proteins in the intestinal tissues of mice 10 days after TBI. We also showed that HBO therapy improved microbiome abundance and probiotic (particularly g_Bifidobacterium) colonisation in mice post-CCI. Then, we identified that the m6A level imcreased notably in injured cortical tissue of CCI+HBO group compared with the CCI group following CCI. Thus, our results suggested that HBO therapy could alleviate TBI-induced intestinal dysfunction and m6A might participate in this regulation process, which provides new insights for exploring the specific mechanism and targets of HBO in the treatment of intestinal dysfunction after TBI, thereby improving the therapeutic effect of HBO.

A taxonomy for superficial cerebral cavernous malformations: subtypes of cortical and subcortical lesions.

A taxonomy for superficial cerebral cavernous malformations (CMs), those based cortically in gyral gray matter or subcortically in underlying white matter, is proposed to build on the comprehensive, systematic characterization of CMs in the entire brain. Patients with superficial cerebral CMs were retrospectively analyzed from a consecutive surgical series between November 2008 and June 2021 at the authors' center. Superficial cerebral CMs were categorized into 4 subtypes based on their cortical location or, if subcortical, proximity to the nearest cerebral surface: convexity, medial, basal, and sylvian. Lobar location was also included for subtyping: frontal, temporal, parietal, and occipital. A total of 362 CMs were resected in 346 patients. CM subtypes were as follows: 132 (36.5%) convexity, 78 (21.5%) medial, 72 (19.9%) basal, and 80 (22.1%) sylvian. Frontal CMs were most common (155 [42.8%]), followed by parietal (89 [24.6%]), temporal (87 [24.0%]), and occipital (31 [8.6%]). Of all CMs, 302 (83.4%) were cortical and 60 (16.6%) were subcortical. The mean subcortical depth of deep lesions was 2.97 cm, and the mean lesion volume was 4.68 cm3. Overall, 228 lesions (63.0%) were resected through a transgyral approach, and 134 (37.0%) were resected through a transsulcal approach. Good outcomes (modified Rankin Scale [mRS] score ≤ 2) were observed in 314 patients (86.7%) and poor outcomes (mRS score > 2) in 25 patients (6.9%), and 23 patients (6.4%) were lost to late follow-up (mean follow-up duration 11.5 months). Relative outcomes were good (unchanged or improved mRS score) in 327 patients (90.3%) and poor (worse or died) in 35 patients (9.7%). Superficial cerebral CMs were resected through a gyrus or sulcus to open the subarachnoid dissection corridors, traversing the full extent of sulci to deepen the approach and minimize tissue transgression. Transgyral dissection avoids associated arteries but is inherently transgressive, whereas transsulcal dissection preserves cortical tissue and may reduce morbidity. Superficial cerebral CMs occupy the largest territory of the 7 types, and the size and surface complexity of the cerebrum make taxonomic subtyping valuable for clear anatomical description.

Retinoic acid alleviates the reduction of Akt and Bad phosphorylation and regulates Bcl-2 family protein interactions in animal models of ischemic stroke.

Ischemic stroke causes a lack of oxygen and glucose supply to brain, eventually leads to severe neurological disorders. Retinoic acid is a major metabolic product of vitamin A and has various biological effects. The PI3K-Akt signaling pathway is an important survival pathway in brain. Phosphorylated Akt is important in regulating survival and apoptosis. We examined whether retinoic acid has neuroprotective effects in stroke model by regulating Akt and its downstream protein, Bad. Moreover, we investigated the relationship between retinoic acid and Bcl-2 family protein interactions. Animals were intraperitoneally administered vehicle or retinoic acid (5 mg/kg) for four days before surgery and ischemic stroke was induced by middle cerebral artery occlusion (MCAO) surgery. Neurobehavioral tests were performed 24 h after MCAO and cerebral cortical tissues were collected. Cresyl violet staining and TUNEL histochemistry were performed, Western blot and immunoprecipitation analysis were performed to elucidate the expression of various proteins. Retinoic acid reduced neurological deficits and histopathological changes, decreased the number of TUNEL-positive cells, and alleviated reduction of phospho-PDK1, phospho-Akt, and phospho-Bad expression caused by MCAO damage. Immunoprecipitation analysis showed that MCAO damage reduced the interaction between phospho-Bad and 14-3-3, which was attenuated by retinoic acid. Furthermore, retinoic acid mitigated the increase in Bcl-2/Bad and Bcl-xL/Bad binding levels and the reduction in Bcl-2/Bax and Bcl-xL/Bax binding levels caused by MCAO damage. Retinoic acid alleviated MCAO-induced increase of caspase-3 and cleaved caspase-3 expression. We demonstrate that retinoic acid prevented apoptosis against cerebral ischemia through phosphorylation of Akt and Bad, maintenance of phospho-Bad and 14-3-3 binding, and regulation of Bcl-2 family protein interactions. .

An exhausted-like microglial population accumulates in aged and APOE4 genotype Alzheimer’s brains

The dominant risk factors for late-onset Alzheimer's disease (AD) are advanced age and the APOE4 genetic variant. To examine how these factors alter neuroimmune function, we generated an integrative, longitudinal single-cell atlas of brain immune cells in AD model mice bearing the three common human APOE alleles. Transcriptomic and chromatin accessibility analyses identified a reactive microglial population defined by the concomitant expression of inflammatory signals and cell-intrinsic stress markers whose frequency increased with age and APOE4 burden. An analogous population was detectable in the brains of human AD patients, including in the cortical tissue, using multiplexed spatial transcriptomics. This population, which we designate as terminally inflammatory microglia (TIM), exhibited defects in amyloid-β clearance and altered cell-cell communication during aducanumab treatment. TIM may represent an exhausted-like state for inflammatory microglia in the AD milieu that contributes to AD risk and pathology in APOE4 carriers and the elderly, thus presenting a potential therapeutic target for AD.

Taphonomy of a Mysticete Whale from the Lower Pliocene of the Coast of Cádiz (Spain)

A fossil mysticete was discovered along the southwestern coast of Spain, occurring in a block detached from the Neogene deposits exposed along a coastal cliff at the locality of Conil de la Frontera (Cádiz, Spain). These deposits range from Pliocene to Pleistocene in age and include shallow-marine, mixed carbonate–siliciclastic sediments, with the whale being found in occurrence of a stratigraphic unconformity marked by Thalassinoides burrows. 87Sr/86Sr analyses on oyster shells associated with the skeleton suggest an Early Pliocene age, in agreement with the age of the lowermost unit cropping out at the study site. The studied cetacean specimen consists of an articulated, almost complete balaenopteroid skeleton exposed in the field dorsal side up; being contained in an upside-down block, however, it is preserved in ventral disposition. Bones exhibit a low degree of preservation of the cortical bone tissue, which locally features shark bite marks and Osedax traces as well as abundant encrustations of barnacles and ostreids. Two shark teeth were also found near the skeleton. Bones have preserved their main histological features, even though they locally exhibit microcracks, dissolution, substitution by Fe oxides, and microborings. Sediment particles and late diagenetic cements fill the medullary cavities. We propose that the whale carcass experienced refloating before sinking to the seafloor and that the skeleton was probably exposed on the seafloor for some time before being eventually buried.

Cerebral ischemia-induced gene expression changes in diabetic mice from acute to subacute stage

Diabetes is a risk factor for stroke; however, its impact on stroke progression at the genomic level is not well understood. To address this gap, we used transcriptome sequencing to explore the relationship between lncRNA and mRNA expression patterns and the reperfusion duration in the cortex of diabetically induced stroke mice. First, focal ischemia was induced in adult male ob/ob mice, which were then subjected to reperfusion periods of one, three, or seven days. Total RNA was extracted from the ischemic cortical tissue for RNA sequencing, and the resulting reads were aligned to the GRCm38 murine reference genome. A total of 672 mRNAs and 301 lncRNAs were identified as differentially expressed one day post-stroke, 1195 mRNAs and 66 lncRNAs at three days post-stroke, and 1069 mRNAs and 75 lncRNAs at seven days post-stroke. Stage-specific differentially expressed mRNAs were bioinformatically analyzed and found significantly enriched in processes such as apoptosis, angiogenesis, and lipid metabolism at one, three, and seven days post-stroke, respectively. Stage-specific DElncRNA-mRNA cis-regulatory relationships were constructed using these biological processes as examples, revealing the potential roles of four pairs of lncRNA-mRNAs (Gm39787-Lcn2, Gm46111-Drd2, D3300500i16Rik-Fosl1, and Gm41689-Egr1) in apoptosis. Additionally, Gm40237-Tie1 and Gm52352-Pdgfrb are associated with angiogenesis and lipid metabolism, respectively. In conclusion, our study demonstrated that lncRNA and mRNA expression in the cortex of transient focal ischemia-induced diabetic mice undergo extensive alterations, providing insights into complex molecular interactions underlying diabetic stroke.

KRM–II–81 suppresses epileptifom activity across the neural network of cortical tissue from a patient with pharmacoresistant epilepsy

A clinical case of a 19-year-old male patient with pharmacoresistant seizures occurring following parieto-occipital tumor-resection at age 6 is described. Seizure surgery work-up included prolonged video EEG monitoring and head CT without contrast. Seizure focus was localized to the left temporal lobe, and we felt that the patient was an excellent candidate for seizure surgery. The patient underwent a left frontotemporal craniotomy for removal of the seizure focus with intraoperative electrocorticography (ECoG) conducted pre and post resection. ECoG recordings pre- and post-resection confirmed resolution of seizure generation. Imaging obtained immediately postoperatively showed complete resection of the residual tumor with no evidence of recurrence in follow-ups. A year after the surgery the patient is seizure-free but remains on seizure medication. With the patient's consent the excised epileptogenic tissue was used for ex-vivo research studies. The microelectrode recordings confirmed epileptiform activity in the excised tissue incubated in excitatory artificial cerebrospinal fluid. The epileptiform activity in the epileptogenic tissue was suppressed by addition of KRM–II–81, a novel α2/3 subtype preferring GABAA receptor (GABAAR) potentiator with previously demonstrated antiepileptic efficacy in multiple animal models of epilepsy and with reduced potential for CNS side-effects compared to classical benzodiazepine GABAAR potentiators. These findings support the proposition that KRM–II–81 might reduce seizure burden in pharmacoresistant patients.

Repetitive spreading depolarization induces gene expression changes related to synaptic plasticity and neuroprotective pathways.

Spreading depolarization (SD) is a slowly propagating wave of profound depolarization that sweeps through cortical tissue. While much emphasis has been placed on the damaging consequences of SD, there is uncertainty surrounding the potential activation of beneficial pathways such as cell survival and plasticity. The present study used unbiased assessments of gene expression to evaluate that compensatory and repair mechanisms could be recruited following SD, regardless of the induction method, which prior to this work had not been assessed. We also tested assumptions of appropriate controls and the spatial extent of expression changes that are important for in vivo SD models. SD clusters were induced with either KCl focal application or optogenetic stimulation in healthy mice. Cortical RNA was extracted and sequenced to identify differentially expressed genes (DEGs). SDs using both induction methods significantly upregulated 16 genes (vs. sham animals) that included the cell proliferation-related genes FOS, JUN, and DUSP6, the plasticity-related genes ARC and HOMER1, and the inflammation-related genes PTGS2, EGR2, and NR4A1. The contralateral hemisphere is commonly used as control tissue for DEG studies, but its activity could be modified by near-global disruption of activity in the adjacent brain. We found 21 upregulated genes when comparing SD-involved cortex vs. tissue from the contralateral hemisphere of the same animals. Interestingly, there was almost complete overlap (21/16) with the DEGs identified using sham controls. Neuronal activity also differs in SD initiation zones, where sustained global depolarization is required to initiate propagating events. We found that gene expression varied as a function of the distance from the SD initiation site, with greater expression differences observed in regions further away. Functional and pathway enrichment analyses identified axonogenesis, branching, neuritogenesis, and dendritic growth as significantly enriched in overlapping DEGs. Increased expression of SD-induced genes was also associated with predicted inhibition of pathways associated with cell death, and apoptosis. These results identify novel biological pathways that could be involved in plasticity and/or circuit modification in brain tissue impacted by SD. These results also identify novel functional targets that could be tested to determine potential roles in the recovery and survival of peri-infarct tissues.