Fibroblast growth factor 9 activates anti-oxidative functions of Nrf2 through ERK signalling in striatal cell models of Huntington's disease

Exploring Cordycepin as a Neuroprotective Agent in Huntington's Disease: In Vitro and In Vivo Insights

Huntington's disease (HD) is a challenging neurodegenerative disorder linked to Huntingtin (HTT) gene mutation, lacking an effective cure despite numerous therapeutic attempts. Cordyceps sinensis, recognized for its health benefits, particularly its constituent cordycepin, exhibits neuroprotective effects in various neurodegenerative diseases. However, the neuroprotective potential of cordycepin in HD remains insufficiently explored. In this study, in vitro experiments using HD cell models demonstrate that cordycepin treatment enhances cell survival, slightly diminishes mutant HTT aggregates, and improves neuronal formation. In vivo investigations on R6/2 HD transgenic mice reveal a modest increase in body weight and a slight amelioration in pathological aggregates following cordycepin administration, although behavioral changes are not significant. While the underlying mechanisms remain unexplored, the findings suggest cordycepin's promise as a supplementary therapeutic for HD, providing neuroprotective effects and reducing mutant protein aggregates.

Mechanistic insights on the role of Nrf-2 signalling in Huntington's disease

BACKGROUND

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder affecting individuals worldwide. It is characterized by progressive motor dysfunction, cognitive decline, and psychiatric disturbances. The pathogenesis of HD involves oxidative stress, neuroinflammation, and mitochondrial dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2), a key transcription factor regulating cellular responses to redox imbalance and inflammation, has emerged as a potential target for therapeutic intervention.

METHODS

Through the use of a number of different search engines like Scopus, PubMed, Elsevier and Bentham, a literature review was carried out with the keywords 'Huntington's Disease, 'Pathology of HD' and 'Nrf2 signalling pathway'. Using the keywords that were given above, this review was carried out in order to collect the most recent publications and gain an understanding of the breadth of the extensive research that has been conducted on the role of Nrf2 in HD pathogenesis.

RESULTS

Oxidative stress and neuroinflammation significantly contribute to HD progression. Activation of Nrf2 offers neuroprotection by enhancing anti-oxidant defense mechanisms. Furthermore, several signaling pathways, play crucial roles in HD pathophysiology. Pharmacological modulation of these pathways through selective inhibitors or agonists shows promise for the development of new therapeutic strategies.

CONCLUSION

The various downstream pathways such as extracellular signal-related kinase (ERK), phosphoinositide 3-Kinase (PI3-K), 5'-AMP-activated protein kinase (AMPK), Sirtuins, Mitogen-activated protein kinases (MAPK) plays a role in alleviating pathophysiology of HD. Diverse reports of these studies demonstrated PI3-K/AMPK/ERK/Sirtuins activators and MAPK inhibitors as encouraging targets in alleviating HD pathophysiology.

Exploration of the shared gene signatures and molecular mechanisms between Alzheimer's disease and intracranial aneurysm

Although Alzheimer's disease (AD) and intracranial aneurysm (IA) were two different types of diseases that occurred in the brain, ruptured IA (RIA) survivors may experience varying degrees of cognitive dysfunction. Neither AD nor IA is easily recognizable by an early onset so that the incidence of adverse clinical outcomes would be on the rise. Therefore, we focused on the exploration of the shared genes and molecular mechanisms between AD and IA, which would be significant for the efficiency of co-screening and co-diagnosis. Two GEO datasets were selected for the weighted gene co-expression network analysis (WGCNA) and differentially expressed gene screening, obtaining 78 overlapped genes. Next, 9 hub genes were identified by the protein-protein interaction network, including PIK3CA, GAB1, IGF1R, PLCB1, PGR, PDGFRB, PLCE1, FGFR3, and SYNJ1. The interactions among the hub genes, miRNA, and TFs were also explored. Meanwhile, we performed GO and KEGG pathway enrichment analyses for the results of WGCNA and hub genes, which showed that the Ras signaling and Rap1 signaling were the main shared pathogenesis. In conclusion, the present bioinformatics analysis revealed that AD and IA had the shared genes and molecular mechanisms, and these outcomes were associated with inflammation and calcium homeostasis, which could provide research clues for further studies.

miR-196a provides antioxidative neuroprotection via USP15/Nrf2 regulation in Huntington's disease

Huntington's disease (HD) is a devastating neurodegenerative disorder characterized by the accumulation of mutant Huntingtin protein (mHTT) and oxidative stress-induced neuronal damage. Based on previous reports, microRNA-196a (miR-196a) has emerged as a potential therapeutic target due to its neuroprotective effects in various neurodegenerative diseases. However, whether miR-196a functions through antioxidative effects is still unknown. In this study, we demonstrated that HD models, both in vitro and in vivo, exhibit elevated levels of reactive oxygen species (ROS) and increased neuronal death, and miR-196a mitigates ROS levels and reduces cell death in HD cells. Moreover, we elucidated that miR-196a facilitates the translocation of nuclear factor erythroid 2 (Nrf2) into the nucleus, enhancing the transcription of antioxidant genes, including heme oxygenase-1 (HO-1). We further identified ubiquitin-specific peptidase 15 (USP15), a direct target of miR-196a related to the Nrf2 pathway, and USP15 exacerbates mHTT aggregate formation while partially counteracting miR-196a-induced reductions in mHTT levels. Taken together, these findings shed light on the multifaceted role of miR-196a in HD, highlighting its potential as a therapeutic avenue for ameliorating oxidative stress and neurodegeneration in this debilitating disease.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

Desmoglein 2 Functions as a Receptor for Fatty Acid Binding Protein 4 in Breast Cancer Epithelial Cells

Fatty acid binding protein 4 (FABP4) is a secreted adipokine linked to obesity and progression of a variety of cancers. Obesity increases extracellular FABP4 (eFABP4) levels in animal models and in obese breast cancer patients compared with lean healthy controls. Using MCF-7 and T47D breast cancer epithelial cells, we show herein that eFABP4 stimulates cellular proliferation in a time and concentration dependent manner while the non-fatty acid-binding mutant, R126Q, failed to potentiate growth. When E0771 murine breast cancer cells were injected into mice, FABP4 null animals exhibited delayed tumor growth and enhanced survival compared with injections into control C57Bl/6J animals. eFABP4 treatment of MCF-7 cells resulted in a significant increase in phosphorylation of extracellular signal-regulated kinase 1/2 (pERK), transcriptional activation of nuclear factor E2-related factor 2 (NRF2) and corresponding gene targets ALDH1A1, CYP1A1, HMOX1, SOD1 and decreased oxidative stress, while R126Q treatment did not show any effects. Proximity-labeling employing an APEX2-FABP4 fusion protein revealed several proteins functioning in desmosomes as eFABP4 receptor candidates including desmoglein (DSG), desmocollin, junction plankoglobin, desomoplankin, and cytokeratins. AlphaFold modeling predicted an interaction between eFABP4, and the extracellular cadherin repeats of DSG2 and pull-down and immunoprecipitation assays confirmed complex formation that was potentiated by oleic acid. Silencing of DSG2 in MCF-7 cells attenuated eFABP4 effects on cellular proliferation, pERK levels, and ALDH1A1 expression compared with controls.

IMPLICATIONS

These results suggest desmosomal proteins, and in particular desmoglein 2, may function as receptors of eFABP4 and provide new insight into the development and progression of obesity-associated cancers.

The fibroblast growth factor system in cognitive disorders and dementia

Cognitive impairment is the core precursor to dementia and other cognitive disorders. Current hypotheses suggest that they share a common pathological basis, such as inflammation, restricted neurogenesis, neuroendocrine disorders, and the destruction of neurovascular units. Fibroblast growth factors (FGFs) are cell growth factors that play essential roles in various pathophysiological processes via paracrine or autocrine pathways. This system consists of FGFs and their receptors (FGFRs), which may hold tremendous potential to become a new biological marker in the diagnosis of dementia and other cognitive disorders, and serve as a potential target for drug development against dementia and cognitive function impairment. Here, we review the available evidence detailing the relevant pathways mediated by multiple FGFs and FGFRs, and recent studies examining their role in the pathogenesis and treatment of cognitive disorders and dementia.

Physiological and genomic insights into abiotic stress of halophilic archaeon Natrinema altunense 4.1R isolated from a saline ecosystem of Tunisian desert

Halophilic archaea are polyextremophiles with the ability to withstand fluctuations in salinity, high levels of ultraviolet radiation, and oxidative stress, allowing them to survive in a wide range of environments and making them an excellent model for astrobiological research. Natrinema altunense 4.1R is a halophilic archaeon isolated from the endorheic saline lake systems, Sebkhas, located in arid and semi-arid regions of Tunisia. It is an ecosystem characterized by periodic flooding from subsurface groundwater and fluctuating salinities. Here, we assess the physiological responses and genomic characterization of N. altunense 4.1R to UV-C radiation, as well as osmotic and oxidative stresses. Results showed that the 4.1R strain is able to survive up to 36% of salinity, up to 180 J/m² to UV-C radiation, and at 50 mM of H₂O₂, a resistance profile similar to Halobacterium salinarum, a strain often used as UV-C resistant model. In order to understand the genetic determinants of N. altunense 4.1R survival strategy, we sequenced and analyzed its genome. Results showed multiple gene copies of osmotic stress, oxidative stress, and DNA repair response mechanisms supporting its survivability at extreme salinities and radiations. Indeed, the 3D molecular structures of seven proteins related to responses to UV-C radiation (excinucleases UvrA, UvrB, and UvrC, and photolyase), saline stress (trehalose-6-phosphate synthase OtsA and trehalose-phosphatase OtsB), and oxidative stress (superoxide dismutase SOD) were constructed by homology modeling. This study extends the abiotic stress range for the species N. altunense and adds to the repertoire of UV and oxidative stress resistance genes generally known from haloarchaeon.

Fibroblast growth factor 9 reduces TBHP-induced oxidative stress in chondrocytes and diminishes mouse osteoarthritis by activating ERK/Nrf2 signaling pathway

Osteoarthritis (OA) is a degenerative and progressive disease that affects joints. Pathologically, it is characterized by oxidative stress-mediated excessive chondrocyte apoptosis and mitochondrial dysfunction. Fibroblast growth factor 9 (FGF9) has been shown to exert antioxidant effects and prevent degenerative diseases by activating ERK-related signaling pathways. However, the mechanism of FGF9 in the pathogenesis of OA and its relationship with anti-oxidative stress and related pathways are unclear. In this study, mice with medial meniscus instability (DMM) were used as the in vivo model whereas TBHP-induced chondrocytes served as the in vitro model to explore the mechanism underlying the effects of FGF9 in OA and its association with anti-oxidative stress. Results showed that FGF9 reduced oxidative stress, apoptosis, and mitochondrial dysfunction in TBHP-treated chondrocytes and promoted the nuclear translocation of Nrf2 to activate the Nrf2/HO1 signaling pathway. Interestingly, silencing the Nrf2 gene or blocking the ERK signaling pathway abolished the antioxidant effects of FGF9. FGF9 treatment reduced joint space narrowing, cartilage ossification, and synovial thickening in the DMM model mice. In conclusion, the present findings demonstrate that FGF9 can inhibit TBHP-induced oxidative stress in chondrocytes through the ERK and Nrf2-HO1 signaling pathways and prevent the progression of OA in vivo.

Activation of the ERK1/2 pathway mediates the neuroprotective effect provided by calycosin treatment

Calycosin is a natural product extracted from some plant families and exhibits various biological properties. But the effect of calycosin on cerebral ischemia-reperfusion injury has not been fully elucidated. In this study, the neuroprotective effect of calycosin treatment on the differentiated SH-SY5Y cells exposed to OGD was evaluated using MTT and flow cytometry. Rats that were pretreatment with calycosin were subjected to MCAO, neurological behavior scores and brain infarct volume were evaluated. The protein expression of pERK/ERK were assessed using Western blot. siRNA-pERK and U0126 were administered to investigate the impact of the ERK pathway on calycosin preconditioning. The results demonstrated the neuronal viability in the calycosin-treated SH-SY5Y cells increased significantly, and the rate of apoptosis decreased compared with the Oxygen-glucose deprivation only SH-SY5Y cells. Calycosin pretreatment reduced infarct volume and improved neurological outcome in rats subjected to MCAO. Administration of calycosin increased the ratio of pERK/ERK expression, which was down-regulated in ischemia-reperfusion group. Down-regulation of pERK/ERK significantly attenuated the neuroprotective effect induced by calycosin pretreatment in vitro and in vivo. We concluded calycosin treatment could induce a neuroprotective effect against ischemia, which was related to the regulation of the ERK1/2 pathway.

miR-196a enhances polymerization of neuronal microfilaments through suppressing IMP3 and upregulating IGF2 in Huntington's disease

Huntington's disease (HD) is one of the inheritable neurodegenerative diseases, and these diseases share several similar pathological characteristics, such as abnormal neuronal morphology. miR-196a is a potential target to provide neuroprotective functions, and has been reported to enhance polymerization of neuronal microtubules in HD. While microtubules and microfilaments are two important components of the neuronal cytoskeleton, whether miR-196a improves neuronal microfilaments is still unknown. Here, we identify insulin-like growth factor 2 mRNA binding protein 3 (IMP3), and show that miR-196a directly suppresses IMP3 to increase neurite outgrowth in neurons. In addition, IMP3 disturbs neurite outgrowth in vitro and in vivo, and worsens the microfilament polymerization. Moreover, insulin-like growth factor-II (IGF2) is identified as the downstream target of IMP3, and miR-196a downregulates IMP3 to upregulate IGF2, which increases microfilamental filopodia numbers and activates Cdc42 to increase neurite outgrowth. Besides, miR-196a increases neurite outgrowth through IGF2 in different HD models. Finally, higher expression of IMP3 and lower expression IGF2 are observed in HD transgenic mice and patients, and increase the formation of aggregates in the HD cell model. Taken together, miR-196a enhances polymerization of neuronal microfilaments through suppressing IMP3 and upregulating IGF2 in HD, supporting the neuroprotective functions of miR-196a through neuronal cytoskeleton in HD.

New developments in the biology of fibroblast growth factors

The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.

Roles of the fibroblast growth factor signal transduction system in tissue injury repair

Following injury, tissue autonomously initiates a complex repair process, resulting in either partial recovery or regeneration of tissue architecture and function in most organisms. Both the repair and regeneration processes are highly coordinated by a hierarchy of interplay among signal transduction pathways initiated by different growth factors, cytokines and other signaling molecules under normal conditions. However, under chronic traumatic or pathological conditions, the reparative or regenerative process of most tissues in different organs can lose control to different extents, leading to random, incomplete or even flawed cell and tissue reconstitution and thus often partial restoration of the original structure and function, accompanied by the development of fibrosis, scarring or even pathogenesis that could cause organ failure and death of the organism. Ample evidence suggests that the various combinatorial fibroblast growth factor (FGF) and receptor signal transduction systems play prominent roles in injury repair and the remodeling of adult tissues in addition to embryonic development and regulation of metabolic homeostasis. In this review, we attempt to provide a brief update on our current understanding of the roles, the underlying mechanisms and clinical application of FGFs in tissue injury repair.

The regulatory roles of microRNAs toward pathogenesis and treatments in Huntington's disease

Huntington's disease (HD) is one of neurodegenerative diseases, and is defined as a monogenetic disease due to the mutation of Huntingtin gene. This disease affects several cellular functions in neurons, and further influences motor and cognitive ability, leading to the suffering of devastating symptoms in HD patients. MicroRNA (miRNA) is a non-coding RNA, and is responsible for gene regulation at post-transcriptional levels in cells. Since one miRNA targets to several downstream genes, it may regulate different pathways simultaneously. As a result, it raises a potential therapy for different diseases using miRNAs, especially for inherited diseases. In this review, we will not only introduce the update information of HD and miRNA, but also discuss the development of potential miRNA-based therapy in HD. With the understanding toward the progression of miRNA studies in HD, we anticipate it may provide an insight to treat this devastating disease, even applying to other genetic diseases.

The Role of Autophagy in Anti-Cancer and Health Promoting Effects of Cordycepin

Cordycepin is an adenosine derivative isolated from Cordyceps sinensis, which has been used as an herbal complementary and alternative medicine with various biological activities. The general anti-cancer mechanisms of cordycepin are regulated by the adenosine A3 receptor, epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (MAPKs), and glycogen synthase kinase (GSK)-3β, leading to cell cycle arrest or apoptosis. Notably, cordycepin also induces autophagy to trigger cell death, inhibits tumor metastasis, and modulates the immune system. Since the dysregulation of autophagy is associated with cancers and neuron, immune, and kidney diseases, cordycepin is considered an alternative treatment because of the involvement of cordycepin in autophagic signaling. However, the profound mechanism of autophagy induction by cordycepin has never been reviewed in detail. Therefore, in this article, we reviewed the anti-cancer and health-promoting effects of cordycepin in the neurons, kidneys, and the immune system through diverse mechanisms, including autophagy induction. We also suggest that formulation changes for cordycepin could enhance its bioactivity and bioavailability and lower its toxicity for future applications. A comprehensive understanding of the autophagy mechanism would provide novel mechanistic insight into the anti-cancer and health-promoting effects of cordycepin.

The Role of Intestinal Microbiota in Colorectal Cancer

Colorectal cancer is a multifactorial disease involving genetic, environmental, and lifestyle risk factors. Intestinal microbiota plays an important role in the occurrence and development of colorectal cancer. Studies have shown that the behavior of intestinal microbiota can lead to pathological changes in the host intestine, which can be divided into epigenetic changes and carcinogenic changes at the gene level, and ultimately promote the formation and development of colorectal cancer. Intestinal microbiota is mainly distributed in the intestinal epithelium, which is composed of a large number of microorganisms interacting with the host intestinal cells. It can affect the immune-inflammation and metabolism of the gastrointestinal tract, and may be used as a biomarker for disease diagnosis. Regulation of gut microbiota is a promising strategy for the prevention and treatment of colorectal cancer. This article reviews the role of intestinal microbiota in the development of colorectal cancer, including the related mechanisms of intestinal microbiota promoting colorectal cancer, the use of intestinal microbiota in the diagnosis of colorectal cancer, and the regulation of intestinal microbiota in the prevention or treatment of colorectal cancer.

Gastrodin protects against high glucose-induced cardiomyocyte toxicity via GSK-3β-mediated nuclear translocation of Nrf2

Diabetic cardiomyopathy (DCM) is one of the major complications of diabetes that causes mortality and morbidity in diabetic patients. Gastrodin (GSTD) is a bioactive phenolic glucoside component of an ancient Chinese herb Tianma (Gastrodia elata Bl.), which is widely used for cardiovascular and cerebrovascular diseases by ancient Chinese. Up to now, whether GSTD has a beneficial effect on DCM is unclear. Therefore, this study aimed to investigate the effect of GSTD on high glucose-induced injury in H9c2 rat cardiomyocytes and HL-1 mouse cardiomyocytes, and its underlying mechanisms. High glucose (33 mM) treatment caused cardiomyocyte toxicity, oxidative stress and apoptosis in both H9c2 and HL-1 cells. Under both normal (5.5 mM glucose) and high glucose conditions, GSTD showed protective effect against high glucose-induced cytotoxicity and promoted the nuclear translocation of Nrf2 in a concentration and time-dependent manner in H9c2 and HL-1 cells. Knockdown of Nrf2 expression using siRNA specifically targeting Nrf2 attenuated the protective effect of GSTD. Furthermore, GSTD promoted the nuclear translocation of Nrf2 via activating glycogen synthase kinse-3β (GSK-3β) signaling pathway. 4-benzyl, 2-methyl, 1, 2, 4-thiadiazolidine, 3, 5 dione (TDZD-8), an inhibitor of GSK-3β, inhibited the nuclear translocation of Nrf2 induced by GSTD, and attenuated the protective effect of GSTD as Nrf2 knockdown did. In summary, GSTD could protect against high glucose-induced cardiomyocyte toxicity via GSK-3β-mediated nuclear translocation of Nrf2.

Mitochondrial and Redox-Based Therapeutic Strategies in Huntington's Disease

Significance: The molecular processes that determine Huntington's disease (HD) pathogenesis are not yet fully understood, and until now no effective neuroprotective therapeutic strategies have been developed. Mitochondria are one of most important organelles required for neuronal homeostasis, by providing metabolic pathways relevant for energy production, regulating calcium homeostasis, or controlling free radical generation and cell death. Because augmented reactive oxygen species (ROS) accompanied by mitochondrial dysfunction are relevant early HD mechanisms, targeting these cellular mechanisms may constitute relevant therapeutic approaches. Recent Advances: Previous findings point toward a close relationship between mitochondrial dysfunction and redox changes in HD. Mutant huntingtin (mHTT) can directly interact with mitochondrial proteins, as translocase of the inner membrane 23 (TIM23), disrupting mitochondrial proteostasis and favoring ROS production and HD progression. Furthermore, abnormal brain and muscle redox signaling contributes to altered proteostasis and motor impairment in HD, which can be improved with the mitochondria-targeted antioxidant mitoquinone or resveratrol, an SIRT1 activator that ameliorates mitochondrial biogenesis and function. Critical Issues: Various antioxidants and metabolic enhancers have been studied in HD; however, the real outcome of these molecules is still debatable. New compounds have proven to ameliorate mitochondrial and redox-based signaling pathways in early stages of HD, potentially precluding selective neurodegeneration. Future Directions: Unraveling the molecular etiology of deregulated mitochondrial function and dynamics, and oxidative stress opens new prospects for HD therapeutics. In this review, we explore the role of redox unbalance and mitochondrial dysfunction in HD progression, and further describe advances on clinical trials in HD based on mitochondrial and redox-based therapeutic strategies.

Fibroblast Growth Factor 9 Stimulates Neuronal Length Through NF-kB Signaling in Striatal Cell Huntington's Disease Models

Proper development of neuronal cells is important for brain functions, and impairment of neuronal development may lead to neuronal disorders, implying that improvement in neuronal development may be a therapeutic direction for these diseases. Huntington's disease (HD) is a neurodegenerative disease characterized by impairment of neuronal structures, ultimately leading to neuronal death and dysfunctions of the central nervous system. Based on previous studies, fibroblast growth factor 9 (FGF9) may provide neuroprotective functions in HD, and FGFs may enhance neuronal development and neurite outgrowth. However, whether FGF9 can provide neuronal protective functions through improvement of neuronal morphology in HD is still unclear. Here, we study the effects of FGF9 on neuronal length in HD and attempt to understand the related working mechanisms. Taking advantage of striatal cell lines from HD knock-in mice, we found that FGF9 increases total neuronal length and upregulates several structural and synaptic proteins under HD conditions. In addition, activation of nuclear factor kappa B (NF-kB) signaling by FGF9 was observed to be significant in HD cells, and blockage of NF-kB leads to suppression of these structural and synaptic proteins induced by FGF9, suggesting the involvement of NF-kB signaling in these effects of FGF9. Taken these results together, FGF9 may enhance total neuronal length through upregulation of NF-kB signaling, and this mechanism could serve as an important mechanism for neuroprotective functions of FGF9 in HD.

Antioxidants and Neuron-Astrocyte Interplay in Brain Physiology: Melatonin, a Neighbor to Rely on

This manuscript is a review focused onto the role of astrocytes in the protection of neurons against oxidative stress and how melatonin can contribute to the maintenance of brain homeostasis. The first part of the review is dedicated to the dependence of neurons on astrocytes by terms of survival under oxidative stress conditions. Additionally, the effects of melatonin against oxidative stress in the brain and its putative role in the protection against diseases affecting the brain are highlighted. The effects of melatonin on the physiology of neurons and astrocytes also are reviewed.

FGF9 induces neurite outgrowth upon ERK signaling in knock-in striatal Huntington's disease cells

AIMS

Huntington's disease (HD) is a neurodegenerative disease that causes deficits in neurite outgrowth, which suggests that enhancement of neurite outgrowth is a potential direction by which to improve HD. Our previous publications showed that fibroblast growth factor 9 (FGF9) provides anti-apoptosis and anti-oxidative functions in striatal cell models of HD through the extracellular signal-regulated kinases (ERK) pathway, and FGF9 also stimulates cytoskeletons to enhance neurite outgrowth via nuclear factor kappa B (NF-kB) signaling. In this study, we further demonstrate the importance of the ERK pathway for the neurite outgrowth induced by FGF9 in HD striatal models.

MATERIALS AND METHODS

FGF9 was treated with ERK (U0126) or NF-kB (BAY11-7082) inhibitors in STHdh^Q7/Q7 and STHdh^Q111/Q111 striatal knock-in cell lines to examine neurite outgrowth, cytoskeletal markers, and synaptic proteins via immunofluorescence staining and Western blotting. NF-kB activity was analyzed by NF-kB promoter reporter assay.

KEY FINDINGS

Here, we show that suppression of ERK signaling significantly inhibits FGF9-induced neurite outgrowth, cytoskeletal markers, and synaptic proteins in HD striatal cells. In addition, we also show suppression of ERK signaling significantly decreases FGF9-induced NF-kB activation, whereas suppression of NF-kB does not decrease FGF9-induced ERK signaling. These results suggest that FGF9 activates ERK signaling first, stimulates NF-kB upregulation, and then enhances neurite outgrowth in HD striatal cells.

SIGNIFICANCE

We elucidate the more detailed mechanisms of neurite outgrowth enhanced by FGF9 in these HD striatal cells. This study may provide insights into targeting neurite outgrowth for HD therapy.

Impacts of exercise interventions on different diseases and organ functions in mice

Background

In recent years, much evidence has emerged to indicate that exercise can benefit people when performed properly. This review summarizes the exercise interventions used in studies involving mice as they are related to special diseases or physiological status. To further understand the effects of exercise interventions in treating or preventing diseases, it is important to establish a template for exercise interventions that can be used in future exercise-related studies.

Methods

PubMed was used as the data resource for articles. To identify studies related to the effectiveness of exercise interventions for treating various diseases and organ functions in mice, we used the following search language: (exercise [Title] OR training [Title] OR physical activity [Title]) AND (mice [title/abstract] OR mouse [title/abstract] OR mus [title/abstract]). To limit the range of search results, we included 2 filters: one that limited publication dates to "in 10 years" and one that sorted the results as "best match". Then we grouped the commonly used exercise methods according to their similarities and differences. We then evaluated the effectiveness of the exercise interventions for their impact on diseases and organ functions in 8 different systems.

Results

A total of 331 articles were included in the analysis procedure. The articles were then segmented into 8 systems for which the exercise interventions were used in targeting and treating disorders: motor system (60 studies), metabolic system (45 studies), cardio-cerebral vascular system (58 studies), nervous system (74 studies), immune system (32 studies), respiratory system (7 studies), digestive system (1 study), and the system related to the development of cancer (54 studies). The methods of exercise interventions mainly involved the use of treadmills, voluntary wheel-running, forced wheel-running, swimming, and resistance training. It was found that regardless of the specific exercise method used, most of them demonstrated positive effects on various systemic diseases and organ functions. Most diseases were remitted with exercise regardless of the exercise method used, although some diseases showed the best remission effects when a specific method was used.

Conclusion

Our review strongly suggests that exercise intervention is a cornerstone in disease prevention and treatment in mice. Because exercise interventions in humans typically focus on chronic diseases, national fitness, and body weight loss, and typically have low intervention compliance rates, it is important to use mice models to investigate the molecular mechanisms underlying the health benefits from exercise interventions in humans.

Neuroprotection by urate on the mutant hSOD1-related cellular and Drosophila models of amyotrophic lateral sclerosis: Implication for GSH synthesis via activating Akt/GSK3β/Nrf2/GCLC pathways

Oxidative stress has been considered as a principal mechanism of motor neuron death in amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease which could be caused by dominant mutations in an antioxidant enzyme superoxide dismutase-1 (SOD1). The aim of the present study was to investigate the potential neuroprotective effects and mechanisms of urate, an important endogenous antioxidant and a biomarker of favorable ALS progression rates, in the mutant human SOD1-related cellular and Drosophila models of ALS. Our results showed that urate treatment provided neuroprotective effects as confirmed by enhanced survival, attenuated motor impairments, reduced oxidative damage and increased antioxidant defense in hSOD1-G85R-expressing Drosophila models of ALS. In vitro studies, we demonstrated that urate protected motor neurons (NSC-34 cells) against hSOD1-G93A-induced cell damage and apoptosis by decreasing reactive oxygen specials (ROS) production and oxidative damage. Moreover, urate markedly increased the expression and activation of nuclear factor erythroid 2-related factor 2 (Nrf2), stimulated Nrf2-targeted antioxidant gene glutathione cysteine ligase catalytic subunit (GCLC) expression and glutathione (GSH) synthesis by upregulating Akt/GSK3β pathway. Furthermore, the inhibition of Akt pathway with LY294002 abolished urate-mediated elevation of GSH synthesis and neuroprotective effects both in vivo and in vitro. Overall, these results suggested that, in addition to its direct scavenging of ROS, urate markedly enhanced GSH expression by activating Akt/GSK3β/Nrf2/GCLC pathway, and thus offering neuroprotective effects on motor neurons against oxidative stress.