Search Results (414)

Although the pathogenesis of the neurodegenerative phenomena of Huntington’s disease (HD) is not well known, in the last 30 years, numerous data have been published that suggest a possible role of oxidative stress. The majority of studies regarding this issue were performed in different experimental models of this disease (neurotoxic models such as intraperitoneal injection of 3-nitropropionic acid or intrastriatal injection of quinolinic acid, transgenic animal models for HD, and cell cultures) and, less frequently, in samples of brain tissue, plasma/serum, blood cells, and other tissues from patients with a genetic–molecular diagnosis of presymptomatic and symptomatic HD compared to healthy controls. In this narrative review, we have summarized the data from the main studies in which oxidative stress parameters have been measured both in patients with HD and in experimental models of the same disease, as well as the few studies on gene variants involved in oxidative stress in patients with HD. Most studies addressing this issue in experimental models of HD have shown an increase in markers or oxidative stress, a decrease in antioxidant substances, or both. However, the results of studies on patients with HD have not been conclusive as few studies have been published on the matter. However, a meta-analysis of blood studies on HD patients (including a pool of serum and blood cell studies) has shown an increase in lipid peroxidation markers, OH8dG concentrations, and GPx activity and a decrease in GSH levels. Future prospective and multicenter studies with a long-term follow-up period involving a large number of HD patients and healthy controls are needed to address this topic. Full article

Methamphetamine (METH) use is frequent among people with HIV (PWH) and appears to increase the risk of neuronal injury and neurocognitive impairment (NCI). This study explored in vivo the effects of a 12 week (long-term), low-dose METH regimen in a transgenic animal model of neuroHIV with inducible expression of HIV-1 transactivator of transcription (Tat). Seven months after transient Tat induction and five months after METH exposure ended, we detected behavioral changes in the Barnes maze (BM) spatial memory task in the Tat and METH groups but not the combined Tat + METH group. The novel object recognition (NOR) task revealed that Tat extinguished discrimination in female animals with and without METH, although METH alone slightly improved NOR. In contrast, in males, Tat, METH, and Tat + METH all compromised NOR. Neuropathological examination detected sex-dependent and brain region-specific changes of pre-synaptic terminals, neurites, and activation of astrocytes and microglia. RNA-sequencing and quantitative reverse transcription polymerase chain reaction indicated that METH and Tat significantly altered gene expression, including factors linked to Alzheimer’s disease-like NCI. In summary, chronic low-dose METH exerts long-term effects on behavioral function, neuropathology, and mRNA expression, and modulates the effects of Tat, suggesting sex-dependent and -independent mechanisms may converge in HIV brain injury and NCI. Full article

Stilbenes are a class of natural polyphenols with multiple positive pharmacologic assets such as antioxidant, anti-inflammatory and anticancer effects. While monomeric stilbenes, represented mostly by resveratrol and pterostilbene, have been studied intensely in the last two decades, oligomeric compounds, which may have better prospects of becoming potent nutraceuticals, are much less studied. The goal of this review is to compile all available literature to date on the beneficial pharmacologic effects of Gnetin C, a resveratrol dimer, in cancer and other diseases. While studies have shown the beneficial effects of Gnetin C, as a single compound or a component of melinjo seed extract, through cellular models, in vivo preclinical studies are still lacking. This is except for prostate cancer, where various animal models, including xenografts and transgenic mice, have been used to evaluate Gnetin C’s more potent anti-inflammatory and anticancer effects compared to resveratrol and its monomeric analogs. Since Gnetin C’s safety has already been demonstrated in healthy volunteers, it is now logical to evaluate its efficacy for prostate cancer chemoprevention, interception and therapy in clinical trials. Full article

A substantial body of research suggests that early-life stress (ELS) is associated with neuropathology in adulthood. Maternal deprivation (MD) is a commonly utilised model in mice for the study of specific neurological diseases. The appropriate growth of dendrites is essential for the optimal functioning of the nervous system. However, the impact of ELS on interneuron dendritic morphology remains unclear. To ascertain whether ELS induces alterations in the morphology of GABAergic inhibitory interneurons in layers II/III of the medial entorhinal cortex (mEC), the somatosensory cortex (SSC), the motor cortex (MC), and the CA1 region of the hippocampus (Hp), 9-day-old male GAD-67-EGFP transgenic mice were subjected to a 24 h MD. At postnatal day 60 (P60), the animals were sacrificed, and their brains were subjected to morphological analyses. The results indicated that MD affected the dendritic morphology of GABAergic interneurons. The mean dendritic length and mean dendritic segments of the examined cortical areas, except for the MC, were significantly decreased, whereas the number of primary dendrites was unaffected. Furthermore, the density of GAD67-EGFP-positive interneurons was decreased in the mEC and Hp, but not in the somatosensory and MC. The induction of ELS through MD in a developmental time window when significant morphological changes occur rendered the developing cells particularly susceptible to stress, resulting in a significant reduction in the number of surviving interneurons at the adult stage. Full article

In animals, a trade-off exists between reproduction and growth, which are the most fundamental traits. Males and females exhibit profound differences in reproduction and growth in fish species. However, the precise molecular mechanism governing this phenomenon is still not clear. Here, we uncovered that chr23-miR-200s and dmrt1 knockout specifically caused an impairment in reproduction and an increase in body growth in female and male zebrafish, respectively. Chr23-miR-200s and Dmrt1 directly regulate the stat5b gene by targeting its 3′UTR and promoter. The loss of stat5b completely abolished the elevated growth performance in chr23-miR-200s-KO or dmrt1^−/− zebrafish. Moreover, the dmrt1 transgenic zebrafish had significantly lower body length and body weight than the control males, accompanied by a significant reduction in stat5b expression in the liver of transgenic fish. In summary, our study proposes a regulatory model elucidating the roles of chr23-miR-200s and Dmrt1 in controlling the sexually dimorphic trade-off between reproduction and growth. Full article

Due to a continuous increase in life expectancy and the progress made in specialized healthcare, the incidence of Alzheimer’s disease (AD) has dramatically increased to the point that it has become one of the main challenges of contemporary medicine. Despite a huge scientific and clinical effort, current treatments manage just a temporary alleviation of symptomatology but offer no cure. Modern trials involving cell transplantation in experimental animals require the involvement of neurosurgeons in the treatment protocol. CSF shunting, intraventricular infusions, or DBS for symptoms relief have been an integral part of the therapeutic arsenal from the very beginning. The development of stereotactic surgery has facilitated the experimental potential of cell transplantation in the hippocampus for Alzheimer’s disease. We conducted a narrative review of the literature in the top three medical databases (PubMed, Science Direct, and Google Scholar) using the keywords “Alzheimer’s disease”, “hippocampus”, and “transplant”. After eliminating duplicates, 241 papers were selected and screened by title and abstract. Two reviewers independently analyzed the 88 papers and chose 32 experiments that involved stereotactic hippocampal transplantation of cells in experimental animals with AD. The stereotactic transplantation of cells such as mesenchymal stem cells (MSCs), neuronal stem cells (NSCs), induced pluripotent cells (iPSCs), astrocytes, and derivates from stem cells was analyzed. The experiments used either a chemically induced or transgenic AD model and observed the impact of the stereotactic transplantation with behavioral testing, MRS spectroscopy, and biochemical analysis. The stereotaxic method delivers minimal invasive treatment option by cell transplantation at the hippocampus. The results showed that amyloid deposits were lower after transplantation, showing a positive impact. Other impactful results involve proliferation of neurogenesis, downregulation of anti-inflammatory response, and increased neuronal plasticity. The increased precision with which the stereotaxic method manages to target deep structures of the brain and the results of the reviewed papers could represent an argument for future human trials. More studies are needed to confirm the viability of the transplanted cells and the long-term effects. Full article

Candida species, normally part of the healthy human flora, can cause severe opportunistic infections when their population increases. This risk is even greater in immunocompromised individuals. Women using intrauterine contraceptive devices (IUDs) are at higher risk for IUD-associated vulvovaginal candidiasis (VVC) because the device provides a surface for biofilm formation. This biofilm formation allows the normal flora to become opportunistic pathogens, leading to symptoms of VVC such as hemorrhage, pelvic pain, inflammation, itching and discharge. VVC is often linked to IUD use, requiring the prompt removal of these devices for effective treatment. This study evaluated the activity of the arginine-rich peptide “protamine” against Candida albicans, Candida tropicalis and Candida krusei isolated from IUD users who had signs of VVC. The antimicrobial activity was measured using the agar disk diffusion and microbroth dilution methods to determine the minimum inhibitory concentration (MIC). The MIC values of protamine against C. albicans, C. tropicalis and C. krusei are 32 μg mL⁻¹, 64 μg mL⁻¹ and 256 μg mL⁻¹, respectively. The determined MIC of protamine was used for a biofilm inhibition assay by crystal violet staining. Protamine inhibited the biofilm formation of the VVC isolates, and its mechanisms were studied through scanning electron microscopy (SEM) and a reactive oxygen species (ROS) assay. The disruption of cell membranes and the induction of oxidative stress appear to be key mechanisms underlying its anti-candidal effects. The results from an in vitro assay support the potential use of protamine as an antibiofilm agent to coat IUDs in the future for protective purposes. Full article

Chromosome 21 DYRK1A kinase is associated with a variety of neuronal diseases including Down syndrome. However, the functional impact of this kinase at the synapse level remains unclear. We studied a mouse model that incorporated YAC 152F7 (570 kb), encoding six chromosome 21 genes including DYRK1A. The 152F7 mice displayed learning difficulties but their N-methyl-D-aspartate (NMDA)-dependent synaptic long-term potentiation is indistinguishable from non-transgenic animals. We have demonstrated that a presynaptic form of NMDA-independent long-term potentiation (LTP) at the hippocampal mossy fiber was impaired in the 152F7 animals. To obtain insights into the molecular mechanisms involved in such synaptic changes, we analyzed the Dyrk1a interactions with chromatin remodelers. We found that the number of DYRK1A-EP300 and DYRK1A-CREBPP increased in 152F7 mice. Moreover, we observed a transcriptional decrease in genes encoding presynaptic proteins involved in glutamate vesicle exocytosis, namely Rims1, Munc13-1, Syn2 and Rab3A.To refine our findings, we used a mouse BAC 189N3 (152 kb) line that only triplicates the gene Dyrk1a. Again, we found that this NMDA-independent form of LTP is impaired in this mouse line. Altogether, our results demonstrate that Dyrk1a up-regulation is sufficient to specifically inhibit the NMDA-independent form of LTP and suggest that this inhibition is linked to chromatin changes that deregulate genes encoding proteins involved in glutamate synaptic release. Full article

Background/Objectives: Charcot first described ALS in 1869, but the specific mechanisms that mediate the disease pathology are still not clear. Intense research efforts have provided insight into unique neuroanatomical regions, specific neuronal populations and genetic associations for ALS and other neurodegenerative diseases; however, the experimental results also suggest a convergence of these events to common toxic pathways. We propose that common toxic pathways can be therapeutically targeted, and this intervention will be effective in slowing progression and improving patient quality of life. Here, we focus on understanding the role of IL6 trans-signaling in ALS disease processes. Methods: We leveraged unique mouse models of IL6 trans-signaling that we developed that recapitulate the production of active sIL6R in a genotypic and quantitative fashion observed in humans. Given that the SOD1 transgenic mouse is one of the most highly studied and characterized models of ALS, we bred SOD1^G93A mice with IL6R trans-signaling mice to determine how enhanced trans-signaling influenced symptom onset and pathological processes, including neuromuscular junction (NMJ) denervation, glial activation and motoneuron (MN) survival. Results: The results indicate that in animals with enhanced trans-signaling, symptom onset and pathological processes were accelerated, suggesting a role in disease modification. Administration of an IL6R functional blocking antibody failed to alter accelerated symptom onset and disease progression. Conclusions: Future work to investigate the site-specific influence of enhanced IL6 trans-signaling and the tissue-specific bioavailability of potential therapeutics will be necessary to identify targets for precise therapeutic interventions that may limit disease progression in the 60% of ALS patients who inherit the common Il6R Asp³⁵⁸Ala variant. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social skills and the presence of repetitive and restricted behaviors and interests. The social behavior of the zebrafish (Danio rerio) makes this organism a valuable tool for modeling ASD in order to explore the social impairment typical of this disorder. In addition to transgenic models, exposure of zebrafish embryos to valproic acid (VPA) has been found to produce ASD-like symptoms. This review first sets out to examine the existing literature on adult social behavior in the zebrafish VPA-induced model of autism, and the authors also aim to identify the ideal VPA dosage able to induce a persistent and long-lasting ASD-like phenotype while minimizing the suffering and distress of research animals in compliance with the principles of replacement, refinement, and reduction (3Rs). Full article

Alzheimer’s disease (AD) is the most common cause of dementia, and no cure is currently available. The β-amyloid cascade of AD and neurofibrillary tangles are the basis of the current understanding of AD pathogenesis, driving drug investigation and other discoveries. Up until now, no AD models have entirely validated the β-amyloid cascade hypothesis. AD models must be capable of recapitulating the critical events of this pathology, including β-amyloid plaques and neurofibrillary tangles. The development of plaques is probably derived from the amyloid precursor protein (APP) and presenilin 1 (PS1) familial Alzheimer’s disease (FAD) mutations, while the tangle-like pathology is determined by tau mutations. Transgenic mouse models struggle to replicate the entire spectrum of AD, particularly neuronal death stemming from β-amyloid and tau pathologies. Furthermore, the success of these transgenic mice often relies on the overexpression of APP transgenes enclosing FAD-associated mutations at levels beyond physiological. Ultimate species-specific discrepancies in genome and protein composition between the human and the mouse may hinder the accurate recapitulation of AD pathological events in mouse models. Although none of the AD models fully mirrors human pathology, these experimental in vivo animal models have provided valuable insights into β-amyloid toxicity and the overall pathophysiological basis of AD. Therefore, these experimental models have been widely used in the preclinical evaluation of therapeutic strategies and have played a pivotal role in the development of immunotherapies for AD. In this review, we sum up the main transgenic mouse models used for AD research, whether they are APP mutation-based mice, APP plus presenilin mutation-based mice, or tau mutation-based mice. The specific characteristics of each mouse model and the significance of their use for AD research, focusing on their current advantages and disadvantages, as well as on the progress made and the forthcoming challenges in replicating this neurodegenerative disease, are also highlighted. Full article

Blood flow is an important physiological endpoint to measure cardiovascular performance in animals. Because of their innate transparent bodies, zebrafish is an excellent animal model for assessing in vivo cardiovascular performance. Previously, various helpful methods for measuring blood flow in zebrafish larvae were discovered and developed. However, an optimized method to measure blood flow in adult zebrafish has not been reported. In this paper, the tail fin region was selected as target for blood flow measurements using the Trackmate method, provided by ImageJ platform. Based on power statistic calculations, the aortic vessel at the tail base was selected, and other parameters, such as ambient temperature, were investigated for method standardization, in order to minimize experimental variation. The method was also validated using fenpropathrin and ponatinib, which showed some cardiac alterations in a previous zebrafish study. We also checked the versatility of this method by following the same setup in black tetra and medaka and found that this method performed well. However, our results show that heavy pigmentation, like that found in tiger barb, and overlapping vessels, like those in parrot fish, make it hard for this method to perform well. Overall, an optimized protocol was used for the first time to measure blood flow velocity in adult wild-type zebrafish without the aid of transgenic lines or fluorescent dye. Full article

Obsessive–compulsive disorder (OCD) is a prevalent, chronic, and severe neuropsychiatric disorder that leads to illness-related disability. Despite the availability of several treatments, many OCD patients respond inadequately, because the underlying neural mechanisms remain unclear, necessitating the establishment of many animal models, particularly mouse models, to elucidate disease mechanisms and therapeutic strategies better. Although the development of animal models is ongoing, there remain many comprehensive summaries and updates in recent research, hampering efforts to develop novel treatments and enhance existing interventions. This review summarizes the phenotypes of several commonly used models and mechanistic insights from transgenic models of OCD, such as knockout mouse models. In addition, we present the advantages and limitations of these models and discuss their future in helping further understand the pathophysiology and advanced treatment. Here, we highlight current frontline treatment approaches for OCD, including neuromodulation and surgical interventions, and propose potential future directions. By studying gene mutations and observing phenotypes from available OCD animal models, researchers have classified the molecular signatures of each model reminiscent of changes in brain areas and neural pathways, with the hope of guiding the future selection of the most appropriate models for specific research in the OCD field. Full article

Polyunsaturated fatty acids (PUFAs) such as linoleic acid (18:2, n-6) and α-linolenic acid (18:3, n-3) are essential for the growth, development, and well-being of mammals. However, most mammals, including humans, cannot synthesize n-3 and n-6 PUFAs and these must be obtained through diet. The beneficial effect of converting n-6 polyunsaturated fatty acids (n-6 PUFAs) into n-3 polyunsaturated fatty acids (n-3 PUFAs) has led to extensive research on the flax fatty acid desaturase 3 (Fad3) gene, which encodes fatty acid desaturase. Still, the plant-derived Fad3 gene is used much less in transgenic animals than the Fat-1 gene from Caenorhabditis elegans. To address this problem, we used somatic cell nuclear transfer (SCNT) technology to create codon-optimized Fad3 transgenic cattle. Gas chromatographic analysis showed that the n-3 PUFA content of transgenic cattle increased significantly, and the ratio of n-6 PUFAs to n-3 PUFAs decreased from 3.484 ± 0.46 to about 2.78 ± 0.14 (p < 0.05). In conclusion, Fad3 gene knock-in cattle are expected to improve the nutritional value of beef and can be used as an animal model to study the therapeutic effects of n-3 PUFAs in various diseases. Full article

A notion of the continuous production of amyloid-β (Aβ) via the proteolysis of Aβ-protein-precursor (AβPP) in Alzheimer’s disease (AD)-affected neurons constitutes both a cornerstone and an article of faith in the Alzheimer’s research field. The present Perspective challenges this assumption. It analyses the relevant empirical data and reaches an unexpected conclusion, namely that in AD-afflicted neurons, the production of AβPP-derived Aβ is either discontinued or severely suppressed, a concept that, if proven, would fundamentally change our understanding of the disease. This suppression, effectively self-suppression, occurs in the context of the global inhibition of the cellular cap-dependent protein synthesis as a consequence of the neuronal integrated stress response (ISR) elicited by AβPP-derived intraneuronal Aβ (iAβ; hence self-suppression) upon reaching certain levels. Concurrently with the suppression of the AβPP proteolytic pathway, the neuronal ISR activates in human neurons, but not in mouse neurons, the powerful AD-driving pathway generating the C99 fragment of AβPP independently of AβPP. The present study describes molecular mechanisms potentially involved in these phenomena, propounds novel approaches to generate transgenic animal models of AD, advocates for the utilization of human neuronal cells-based models of the disease, makes verifiable predictions, suggests experiments designed to validate the proposed concept, and considers its potential research and therapeutic implications. Remarkably, it opens up the possibility that the conventional production of AβPP, BACE enzymes, and γ-secretase components is also suppressed under the neuronal ISR conditions in AD-affected neurons, resulting in the dyshomeostasis of AβPP. It follows that whereas conventional AD is triggered by AβPP-derived iAβ accumulated to the ISR-eliciting levels, the disease, in its both conventional and unconventional (triggered by the neuronal ISR-eliciting stressors distinct from iAβ) forms, is driven not (or not only) by iAβ produced in the AβPP-independent pathway, as we proposed previously, but mainly, possibly exclusively, by the C99 fragment generated independently of AβPP and not cleaved at the γ-site due to the neuronal ISR-caused deficiency of γ-secretase (apparently, the AD-driving “substance X” predicted in our previous study), a paradigm consistent with a dictum by George Perry that Aβ is “central but not causative” in AD. The proposed therapeutic strategies would not only deplete the driver of the disease and abrogate the AβPP-independent production of C99 but also reverse the neuronal ISR and ameliorate the AβPP dyshomeostasis, a potentially significant contributor to AD pathology. Full article