bluuebunny/crossref_metadata_2025_split huggingface dataset:
Highly Predictive Objective Measurement of OA Joint Pain in Rat Using Bioseb Automated Dynamic Weight Bearing System
Authors: Rashid Harun , Cornicelli Joe , Young Alan , Samadfam Rana 
Published: November 2023

BackgroundOsteoarthritis (OA) is often associated with chronic debilitating joint pain. Similar pain has been reported in animal models of OA. However, most pain measuring techniques in animal are subjective in nature where reflex responses upon stimulation with nociceptive stimuli are measured. The purpose of the present study is to provide a highly reproducible objective joint pain measuring technique in the mono‐iodoacetate (MIA)‐induced OA model in rats.MethodsJoint pain is induced in rat by a single intra‐articular injection of MIA (3mg/25uL) into the right knee joint. Dynamic weight bearing (DWB) patterns by different limbs and tail in the rats are quantified using the BioSeb automated DWB system. The system consists of an arena box with a pressure‐sensitive sensor mat on the bottom and an attached high‐resolution camera on the top. The rat can move freely inside the arena box. A two‐minute recording is done for each rat. Analysis of dynamic weight bearing data is done off‐line using the BioSeb software. The system automatically calculates the weight borne by each limb and the tail. DWB data are calculated by normalizing as percent of total body weight borne by each limb and tail. Joint pain is indicated by reduction in weight bearing by the MIA‐injected right hind limb. Effects of tramadol, dexamethasone, morphine, naproxen and celecoxib on MIA‐induced joint pain were evaluated at different time points post MIA injection.ResultsBaseline DWB data were assessed across a number of studies and very consistent and reproducible baseline weight bearing pattern was observed. The deficit in weight bearing by the MIA‐injected right hind limb was mostly compensated by extra weight bearing in left hind limb although a smaller portion was also compensated by the right front limb. Weight bearing assessment over a period of four weeks showed that MIA‐induced OA joint pain was often more intense during the first few days post MIA injection, which might be due to the acute inflammation of the joint synovium, and pain is also intense in later time points during the third and fourth week, which might be due to the cartilage damage. Of the various standard of care OA pain relieving agents examined in this model, morphine, tramadol and dexamethasone were effective in both early and late phase of the model while naproxen and celecoxib were effective only during the early phase.ConclusionOverall, the current results suggest that Bioseb dynamic weight system is reliable for objective measurement of OA joint pain in rats. Moreover, results from the validation studies with standard of care OA pain relieving agents also support the biphasic nature of the MIA‐induced OA joint pain whereby the early phase is more sensitive to NSAIDs than the later phase(s).
A Comparative Study of Two Analgesic Compounds, Fenobam Sulfate and Fenobam Free Base, Using a Model of Inflammatory Nociception
Authors: Cox Abigail , Lax Neil , Welsh William , Peng Youyi , Kolber Benedict 
Published: November 2023

A diverse array of chronic pain conditions exist, each with varying causative mechanisms and multiple hypothesized receptor targets for treatment. One potentially effective target for analgesia is the metabotropic glutamate receptor subtype 5 (mGluR5). A selective antagonist of mGluR5, fenobam free base, has been shown to provide pain relief in preclinical models. Due, in part, to fenobam free base's poor solubility and short half‐life, however, it carries limitations for efficacy in human conditions. A new salt formulation of the compound, fenobam sulfate, has improved solubility and a longer half‐life, which may contribute to extended analgesic effects. A comparative study of fenobam sulfate and fenobam free base was performed in male and female mice using the spontaneous formalin pain model. The main objective was to determine if fenobam sulfate shares similar analgesic properties with its free base counterpart. The two compounds were each dissolved in two separate vehicles, DMSO and BCD. Fenobam sulfate produced analgesic effects similar to those of free base when dissolved in either vehicle. Both compounds dissolved in DMSO, however, produced greater analgesic effects compared to BCD. The duration of time in which fenobam sulfate had an effect was also characterized through mechanical hypersensitivity tests two and three hours following formalin injection. Fenobam sulfate in BCD induced analgesia in female mice for at least two hours, but not in male mice. As fenobam free base has been shown to increase locomotion, the impact of fenobam sulfate on locomotion was investigated using an open field assay. Both compounds were found to induce similar increases in locomotive activity. Overall, these results suggest that fenobam sulfate may be a more effective analgesic compound than fenobam free base. In the future, it would be valuable to analyze sex differences that may contribute to the observed prolonged analgesia in female mice.Support or Funding InformationSupported by the American Physiological Society Undergraduate Summer Research Fellowship, the Duquesne University Undergraduate Research Program, and the Duquesne University Pain Undergraduate Research Experience.
Conditional deletion of L‐type calcium channels in oligodendrocyte progenitor cells affects remyelination in mice
Authors: Gonzalez Diara A Santiago , Cheli Veronica T , Spreuer Vilma , Paez Pablo M 
Published: November 2023

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the CNS. Demyelination impairs axon conduction and can lead to deficits in motor, sensory and/or cognitive function depending on the location of the affected axons. Remyelination occurs in many MS lesions, but becomes increasingly less effective over time and eventually fails. Our findings indicate a role for L‐type voltage‐operated calcium channels (L‐VOCCs) as potential modulators of oligodendrocyte progenitor cell (OPC) development in the postnatal mouse brain. To determine whether L‐VOCCs are required for OPC development and remyelination, we have generated an inducible conditional knockout mouse in which the L‐VOCC isoform Cav1.2 was deleted in NG2 positive OPCs. Using the cuprizone model of demyelination we establish that Cav1.2 deletion in OPCs lead to less efficient remyelination of the adult brain. We have found that Cav1.2 deficient OPCs are less effective in remyelinating several structures of the adult brain including the corpus callosum and cortex. Specifically, Cav1.2 KO OPCs mature slower and produce less myelin than control oligodendrocytes after two and four weeks of recovery following the cuprizone intoxication. Furthermore, during the recovery period of the cuprizone model the corpus callosum of Cav1.2 KO animals presented an important decrease in the percentage of myelinated axons and a substantial increase in the mean g‐ratio of myelinated axons compare to controls. These results suggest that Ca++ influx mediated by L‐VOCCs in oligodendroglial progenitor cells is necessary for normal remyelination and is an essential calcium channel for OPC maturation during the remyelination process.Support or Funding InformationNIH/NINDS grant 1R01NS078041‐03A1 and National Multiple Sclerosis Society Grant RG4554‐A‐2.
Antidepressant‐like Effects of Ketamine in Serotonin Transporter Knockout Mice and Organic Cation Transporter 3 Knockout Mice
Authors: Bowman Melodi Ann , Vitela Melissa , Owens W. Anthony , Koek Wouter , Daws Lynette 
Published: November 2023

Twenty percent of adults are diagnosed with major depressive disorder, which is typically treated with selective serotonin reuptake inhibitors. However, this type of medication takes approximately six weeks to produce therapeutic effects. Recently, low doses of ketamine, a noncompetitive N‐methyl‐D‐aspartate (NMDA) receptor antagonist, have been shown to produce rapid and long‐lasting antidepressant effects. Studies that have begun to examine the mechanisms underlying these effects have focused on intracellular changes mediated by NMDA and/or AMPA receptors. However, the traditional view of the etiology of depression involves the need for an increase in extracellular serotonin to regulate mood. Surprisingly, there appears to be little research into the effects of ketamine on serotonin. One study found an increase in extracellular serotonin while another found an inhibition of serotonin uptake following ketamine treatment. Together, these studies suggest a role for serotonin in the antidepressant‐like effects of ketamine, and putatively one involving the serotonin transporter (SERT). In order to investigate this, we performed in vivo chronoamperometry. A nafion coated carbon fiber electrode and four barrel micropipette was inserted into the CA3 region of the hippocampus and serotonin, ketamine, or vehicle was applied exogenously. Our results showed a decrease in clearance rate of serotonin after application of ketamine as well as an increase in signal amplitude. To further elucidate this effect, we examined antidepressant‐like effects of ketamine in SERT knockout mice bred on a C57BL/6J background. SERT knockout and wildtype adult mice were treated with vehicle or ketamine and tested in the tail suspension test. Ketamine had antidepressant‐like effects only in SERT knockout mice. Taken together with published findings that SERT knockout mice have increased expression of organic cation transporter 3 (OCT3) relative to wildtype littermates, and that blockade of OCT3 produces antidepressant‐like effects and inhibits serotonin uptake, we next examined the antidepressant‐like effects of ketamine in OCT3 knockout mice using the forced swim test. Our results indicate that the antidepressant‐like effect of ketamine is attenuated in the OCT3 knockout mice. Ongoing studies are investigating the dose‐response relationship of these effects in SERT and OCT3 knockout mice to investigate a potential role for OCT3 in antidepressant‐like effects of ketamine.Support or Funding InformationThis project was supported by NIH training grant T32 NS082145 funded by the Jointly Sponsored NIH Predoctoral Training Program in Neurosciences and by R01 MH093320 and R01 MH106978
Modulating the balance of synaptic and extrasynaptic NMDA receptors (NMDARs) shows priority over non‐selective NMDAR antagonists against beta‐amyloid induced neurotoxicity
Authors: Huang Yan , Shen Wei , Liu Gang , Zhou Wen‐xia , Zhang Yong‐xiang 
Published: November 2023

Alzheimer's disease (AD) patients suffer a disturbance in the balance between synaptic NMDARs (NR2A, mediating the protective pathway) and extrasynaptic NMDARs (NR2B, mediating the excitotoxic pathway), and restoring the balance of NR2A and NR2B should be beneficial for AD. Aβ treated hippocampal slices and Aβ icv injection animals were used as AD models in this study. Long‐term potentiation (LTP) and behavior test were used to evaluate the effects of drugs and signal pathways were analyzed by Western Blotting. Specific activation of NR2A and inhibition of NR2B showed the best protective effect against Aβ‐induced long‐term potentiation (LTP) deficits. In Aβ icv injection animals, the combination of ifenprodil and D‐cycloserine (a co‐activator of NMDRs similar to D‐serine) showed better protective effects against Aβ‐induced cognitive deficits (nest building, novel object recognition and Morris water maze) than ifenprodil or D‐cycloserine alone. The ratio of NR2A to NR2B, TORC dephosphorylation and ERK1/2 activation (which could be initiated by NR2A) decreased in the hippocampal tissues of Aβ‐treated animals. As a result, the activation of CREB and the content of brain‐derived BDNF decreased. The combination of ifenprodil and D‐cycloserine showed the best protective effects, indicating that Aβ‐induced toxicology was mediated both by inhibiting NR2A and enhancing NR2B. These results indicate that enhancing synaptic NMDARs and inhibiting extrasynaptic NMDARs concurrently showed good effects against Aβ‐induced neurotoxicity, suggesting that modulation of the balance between NR2A and NR2B could be a potential strategy for AD drug development and therapy.Support or Funding InformationProject supported by the National Natural Science Foundation of China (81202505)
Fumaric acid esters as a new therapeutic target for traumatic brain injury
Authors: Esposito Emanuela , Campolo Michela , Casili Giovanna , D'amico Ramona , Lanza Marika , Cuzzocrea Salvatore 
Published: November 2023

Traumatic brain injury (TBI) provokes secondary injury mechanisms, including dynamic interplay between ischemic, inflammatory and cytotoxic processes. Moreover, impact induces massive cell death and outcomes in extensive dendrite degeneration leading to persistent cognitive, sensory and motor dysfunction. Fumaric acid esters (FAEs) were showed beneficial effects in preclinical models of neuro‐inflammation, neurodegeneration, and toxic oxidative stress but its precise mechanism of action remains unclear. Therefore, the aim of the present work was to evaluate the potential beneficial effects of dimethyl fumarate (DMF) and monomethyl fumarate (MMF), the most pharmacologically effective molecules among the FAEs, in a murine model of TBI.TBI was induced in mice by the controlled cortical impact (CCI), one of the most common models of TBI; mice were orally administered with DMF and MMF (both at 30mg/Kg) 1h and 4h after trauma. We observed that mice treated with DMF exhibited a significantly and sustained recovery of motor function. FAEs significantly reduced the severity of inflammation by a modulation of proinflammatory cytokines and apoptosis factors, and increased neurotrophic factors such as BDNF, GDNF and NT‐3. Furthermore, DMF treatment up‐regulated Nrf‐2 pathway, increasing NeuN+/Nrf‐2+ cells in the cortex and inducing activation of manganese superoxide dismutase (Mn‐SOD) and heme‐oxygenase‐1 (HO‐1), regulating glutathione levels too. Our results showed important protective effects of DMF in an animal model of TBI by reducing the secondary inflammation and tissue injury that characterize this model. DMF may constitute a promising target for future TBI therapies.
The Neuroprotective Role of Myeloid Zinc Finger‐1 and Specificity Protein 1 during Treatment with Leukemia Inhibitory Factor
Authors: Davis Stephanie , Collier Lisa , Fazal Jawad , Britton Michael , Leonardo Christopher , Ajmo Craig , Pennypacker Keith 
Published: November 2023

ObjectiveThe objective of this study is to determine whether leukemia inhibitory factor (LIF) induces neuroprotection through the transcription factors myeloid zinc finger‐1 (MZF‐1) and specificity protein 1 (Sp1).MethodsAfter middle cerebral artery occlusion or sham surgery, male Sprague‐Dawley rats were injected with PBS or LIF (125 μg/kg) (n=4 per group). Rats were euthanized 72 h after injury. Western blotting was used to measure MZF‐1 and Sp1 protein expression in brain tissue and spleen tissue. Genomatix was used to identify MZF‐1 and Sp1 binding sites in the promoter of superoxide dismutase 3 (SOD3), a LIF‐inducible gene. Gel shift assays were used to confirm binding of these transcription factors in brain nuclear extracts. Fluorescent immunohistochemistry was used to visualize localization of Sp1, MZF‐1, and SOD3. For in vitro studies, cultured rat neurons were isolated at embryonic day 18 and transfected with scrambled or MZF‐1 siRNA (n=3 per group). Neurons were treated with PBS or 200 ng/mL LIF prior to 24 h in vitro ischemia induced by oxygen glucose deprivation. Lactate dehydrogenase (LDH) release was measured to assess neuronal death. SOD3, Sp1, and MZF‐1 mRNA levels were measured with real‐time PCR. MZF‐1 protein levels were quantified in cultured neurons with immunocytochemistry.ResultsLIF treatment did not significantly alter MZF‐1 or Sp1 expression in the brain at 72 h after MCAO. However, LIF significantly increased expression of MZF‐1 in the spleen at 72 h post‐MCAO compared to the PBS treatment. Four MZF‐1 binding sites and two Sp1 binding sites were identified in the rat SOD3 promoter using Genomatix, and confirmed using gel shift assays. LIF treatment caused nuclear accumulation of MZF‐1 at 72 h after MCAO, while Sp1 and MZF‐1 co‐localized with SOD3 at this time point. In cultured neurons, LIF treatment prior to 24 h in vitro ischemia significantly increased the percentage of MZF‐1‐positive neurons compared to PBS treatment (p<0.01). Real time PCR confirmed the increase in MZF‐1 mRNA LIF‐treated neurons compared to PBS‐treated neurons (p<0.05). In these same samples, LIF increased SOD3 mRNA after 24 h ischemia compared to PBS. Sp1 mRNA was not significantly altered by LIF treatment after 24 h ischemia. However, transfection of cultured neurons with MZF‐1 and Sp1 siRNA counteracted the significant decrease in LDH release observed after LIF treatment alone (p<0.05).ConclusionsLIF induces neuroprotection against ischemia through the transcription factors MZF‐1 and Sp1. Moreover, the LIF‐mediated increase in MZF‐1 activity occurs through increased gene and protein expression in cultured neurons as well as splenic tissueSupport or Funding InformationFunding for experiments in this study was provided for by the National Institute for Neurological Disorders and Stroke (project numbers 1R56NS091146‐01, 7R01NS091146‐02, and 1R01NS091146‐01Al),
Neonatal Erythropoietin Reverses Cognitive Deficits in a Preclinical Model of Encephalopathy of Prematurity
Authors: Jantzie Lauren , Robinson Shenandoah 
Published: November 2023

Preterm infants are prone to numerous neurological deficits including cerebral palsy, epilepsy, sensory processing impairment and intellectual disability. Among the most impactful repercussions of preterm birth, cognitive deficits pose a significant barrier to achieving independent adult living. Touchscreen testing is a novel paradigm for assessing cognitive domains in rodents after brain injury. Previously, we have shown gait deficits and impairment in social interaction observed in adult rats following prenatal transient systemic hypoxia‐ischemia (TSHI) normalized to sham levels following high‐dose erythropoietin (EPO) treatment in the postnatal period. Here, we hypothesized that EPO would induce recovery of chronic cognitive deficits often seen in children born extremely preterm, including executive function, congruent with its beneficial mechanism of action on developing oligodendrocytes and neurons. Accordingly, pregnant rats underwent laparotomy on embryonic day 18, and TSHI was induced via uterine artery occlusion for 60 minutes. Shams had anesthesia and laparotomy for the same duration without arterial clamping. On postnatal day 1 (P1), TSHI pups were randomized to EPO (2000U/kg/dose) or vehicle treatment (sterile saline). Beginning on P35, a touchscreen platform was applied to assess multiple cognitive domains. Specifically, rats were trained on a touchscreen operant platform by blinded investigators, and following successful training, rats performed visual discrimination (VD) and reversal tasks. Data were compared using two‐way ANOVA with posthoc Bonferroni correction, or Kruskal‐Wallis, with p<0.05 as significant. Results indicate that TSHI‐veh, TSHI‐EPO and sham rats meet visual discrimination criteria, showing adequate visual‐cognitive capacity. TSHI‐veh rats showed impaired cognitive flexibility, an executive function also impaired in children born preterm, compared to shams and TSHI‐EPO rats. Specifically, when assessing reversal learning, only 30% of TSHI‐veh animals successfully passed criteria compared to 58% of TSHI animals treated with EPO. Notably, TSHI animals committed significantly more errors and required more correction trials (642±62) compared to Sham (504±41) and CCI‐EPO (441±51, p<0.05 for all), concomitant with increased perseveration (all p<0.05). This is the first time that highly translational touchscreen platforms utilized in both humans and rodents have been successfully used in perinatal brain injury to test repair cognitive and executive function. Further testing with this platform will allow dissection of deficits in distinct pillars of cognition following in utero injury, and the response to novel emerging therapeutic strategies for preterm infants. These data also validate EPO treatment for the mitigation of cognitive disorders following perinatal brain injury.Support or Funding InformationUniversity of New Mexico Johns Hopkins University NIH NINDS
PLC‐Dependent Hydrolysis of Phosphatidylinositol 4‐Phosphate is Responsible for the Majority of Total Inositol Phosphate Production and PKC/D Activation Downstream of Multiple GPCRs
Authors: de Rubio Rafael Gil , Malik Sundeep , Smrcka Alan V 
Published: November 2023

Receptor activation of phospholipase C (PLC) is important for many physiological processes, including neurotransmission and cell proliferation. PLC enzymes are 6 families of proteins that hydrolyze the plasma membrane lipid, phosphatidylinositol 4,5‐bisphosphate (PIP2) into inositol trisphosphate and diacylglycerol (DAG). Our group identified a novel pathway in cardiac cells, where G protein coupled receptor (GPCR) stimulation leads to PLC‐dependent hydrolysis of the PIP2‐precursor, phosphatidylinositol 4‐phosphate (PI4P) on intracellular Golgi membranes. We proposed that this localized DAG production was essential for nuclear processes involved in cardiac hypertrophy.Our hypothesis is that receptor‐stimulated PI4P hydrolysis expands beyond cardiac cells as a mechanism for DAG production without calcium signaling. We measured PI4P in various cell types using PI4P specific binding domains fused to GFP and found that PI4P was depleted both at the Golgi and plasma membrane (PM) in response to GPCR‐stimulation. Since PI4P is the precursor of PIP2, one could argue that depletion of PI4P happens to replenish PIP2 used by PLC and not as an actual substrate. To test this, we depleted PIP2 prior to GPCR stimulation. We used the PM‐targeted FRB/FKBP‐5‐phosphatase rapamycin‐induced dimerization system. After rapamycin addition, the PI‐5‐phosphatase is recruited to the PM where it removes the 5 phosphate from the head group of PIP2. As predicted, depletion of PIP2 did not inhibit GPCR‐stimulated PM or Golgi PI4P depletion, total IP production or PKD activation. In contrast, pharmacological inhibition of PI4‐kinases to deplete PI4P specifically at the PM, without affecting PIP2 levels, completely blocked GPCR‐dependent total IP production and PKD activation. These data strongly suggest that PI4P hydrolysis is the major reaction catalyzed by PLCs in terms of phosphoinositide mass and is a key source of DAG for regulation of protein kinases.While we have identified PI4P hydrolysis in various cell types, it is not clear which PLC isoforms catalyze this reaction. PLC epsilon performs this function at the Golgi‐Nuclear Envelope interface, but all PLC isoforms hydrolyze PI4P in vitro and may participate in PI4P hydrolysis in different cell types. To determine the identity of PLC isoforms responsible for PI4P hydrolysis, we used CRISPR technology to knockout individual PLC isoforms and will assess their roles in total IP production and PKD activation. Ultimately, finding which PLC isoforms are involved may provide new and more specific therapeutic targets for diseases.Support or Funding InformationSupport from NIH, RO1 grants GM053536 and GM111735 (A.V.S.) and NRSA predoctoral grant F31 GM116557 (R.G.).