Combined Metabolomics and Transcriptomics Approaches to Assess the IL-6 Blockade as a Therapeutic of ALS: Deleterious Alteration of Lipid Metabolism

Identification of the abnormalities in astrocytic functions as potential drug targets for neurodegenerative disease

INTRODUCTION

Historically, astrocytes were seen primarily as a supportive cell population within the brain; with neurodegenerative disease research focusing exclusively on malfunctioning neurons. However, astrocytes perform numerous tasks that are essential for maintenance of the central nervous system`s complex processes. Disruption of these functions can have negative consequences; hence, it is unsurprising to observe a growing amount of evidence for the essential role of astrocytes in the development and progression of neurodegenerative diseases. Targeting astrocytic functions may serve as a potential disease-modifying drug therapy in the future.

AREAS COVERED

The present review emphasizes the key astrocytic functions associated with neurodegenerative diseases and explores the possibility of pharmaceutical interventions to modify these processes. In addition, the authors provide an overview of current advancement in this field by including studies of possible drug candidates.

EXPERT OPINION

Glial research has experienced a significant renaissance in the last quarter-century. Understanding how disease pathologies modify or are caused by astrocyte functions is crucial when developing treatments for brain diseases. Future research will focus on building advanced models that can more precisely correlate to the state in the human brain, with the goal of routinely testing therapies in these models.

T cell infiltration mediates neurodegeneration and cognitive decline in Alzheimer's disease

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder with pathological features of β-amyloid (Aβ) and hyperphosphorylated tau protein accumulation in the brain, often accompanied by cognitive decline. So far, our understanding of the extent and role of adaptive immune responses in AD has been quite limited. T cells, as essential members of the adaptive immune system, exhibit quantitative and functional abnormalities in the brains of AD patients. Dysfunction of the blood-brain barrier (BBB) in AD is considered one of the factors leading to T cell infiltration. Moreover, the degree of neuronal loss in AD is correlated with the quantity of T cells. We first describe the differentiation and subset functions of peripheral T cells in AD patients and provide an overview of the key findings related to BBB dysfunction and how T cells infiltrate the brain parenchyma through the BBB. Furthermore, we emphasize the risk factors associated with AD, including Aβ, Tau protein, microglial cells, apolipoprotein E (ApoE), and neuroinflammation. We discuss their regulation of T cell activation and proliferation, as well as the connection between T cells, neurodegeneration, and cognitive decline. Understanding the innate immune response is crucial for providing comprehensive personalized therapeutic strategies for AD.

Mitochondria: A Promising Convergent Target for the Treatment of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the progressive loss of motor neurons, for which current treatment options are limited. Recent studies have shed light on the role of mitochondria in ALS pathogenesis, making them an attractive therapeutic intervention target. This review contains a very comprehensive critical description of the involvement of mitochondria and mitochondria-mediated mechanisms in ALS. The review covers several key areas related to mitochondria in ALS, including impaired mitochondrial function, mitochondrial bioenergetics, reactive oxygen species, metabolic processes and energy metabolism, mitochondrial dynamics, turnover, autophagy and mitophagy, impaired mitochondrial transport, and apoptosis. This review also highlights preclinical and clinical studies that have investigated various mitochondria-targeted therapies for ALS treatment. These include strategies to improve mitochondrial function, such as the use of dichloroacetate, ketogenic and high-fat diets, acetyl-carnitine, and mitochondria-targeted antioxidants. Additionally, antiapoptotic agents, like the mPTP-targeting agents minocycline and rasagiline, are discussed. The paper aims to contribute to the identification of effective mitochondria-targeted therapies for ALS treatment by synthesizing the current understanding of the role of mitochondria in ALS pathogenesis and reviewing potential convergent therapeutic interventions. The complex interplay between mitochondria and the pathogenic mechanisms of ALS holds promise for the development of novel treatment strategies to combat this devastating disease.

Novel therapeutic approaches for motor neuron disease

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that leads to the neurodegeneration and death of upper and lower motor neurons (MNs). Although MNs are the main cells involved in the process of neurodegeneration, a growing body of evidence points toward other cell types as concurrent to disease initiation and propagation. Given the current absence of effective therapies, the quest for other therapeutic targets remains open and still challenges the scientific community. Both neuronal and extra-neuronal mechanisms of cellular stress and damage have been studied and have posed the basis for the development of novel therapies that have been investigated on both animal models and humans. In this chapter, a thorough review of the main mechanisms of cellular damage and the respective therapeutic attempts targeting them is reported. The main areas covered include neuroinflammation, protein aggregation, RNA metabolism, and oxidative stress.

Inflammatory checkpoints in amyotrophic lateral sclerosis: From biomarkers to therapeutic targets

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron damage. Due to the complexity of the ALS, so far the etiology and underlying pathogenesis of sporadic ALS are not completely understood. Recently, many studies have emphasized the role of inflammatory networks, which are comprised of various inflammatory molecules and proteins in the pathogenesis of ALS. Inflammatory molecules and proteins may be used as independent predictors of patient survival and might be used in patient stratification and in evaluating the therapeutic response in clinical trials. This review article describes the latest advances in various inflammatory markers in ALS and its animal models. In particular, this review discusses the role of inflammatory molecule markers in the pathogenesis of the disease and their relationship with clinical parameters. We also highlight the advantages and disadvantages of applying inflammatory markers in clinical manifestations, animal studies, and drug clinical trials. Further, we summarize the potential application of some inflammatory biomarkers as new therapeutic targets and therapeutic strategies, which would perhaps expand the therapeutic interventions for ALS.

New insight into neurological degeneration: Inflammatory cytokines and blood–brain barrier

Neurological degeneration after neuroinflammation, such as that resulting from Alzheimer’s disease (AD), stroke, multiple sclerosis (MS), and post-traumatic brain injury (TBI), is typically associated with high mortality and morbidity and with permanent cognitive dysfunction, which places a heavy economic burden on families and society. Diagnosing and curing these diseases in their early stages remains a challenge for clinical investigation and treatment. Recent insight into the onset and progression of these diseases highlights the permeability of the blood–brain barrier (BBB). The primary factor that influences BBB structure and function is inflammation, especially the main cytokines including IL-1β, TNFα, and IL-6, the mechanism on the disruption of which are critical component of the aforementioned diseases. Surprisingly, the main cytokines from systematic inflammation can also induce as much worse as from neurological diseases or injuries do. In this review, we will therefore discuss the physiological structure of BBB, the main cytokines including IL-1β, TNFα, IL-6, and their mechanism on the disruption of BBB and recent research about the main cytokines from systematic inflammation inducing the disruption of BBB and cognitive impairment, and we will eventually discuss the need to prevent the disruption of BBB.

Fibrinogen-Like Protein 1 as a Novel Biomarker of Psoriasis Severity

Background

Psoriasis is an immune-mediated chronic systemic inflammatory skin disease whose diagnosis and severity assessment pose challenges for clinicians worldwide. The use of serum biomarkers facilitates the early diagnosis and treatment of psoriasis.

Methods

This case–control study compared tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-17, IL-10, and fibrinogen-like protein 1 (FGL1) levels of 139 untreated psoriasis patients and 140 healthy controls. Serum samples were collected, and enzyme-linked immunosorbent assays were performed to quantify their levels. Subgroups were analyzed according to abnormal lipid metabolism status.

Results

Compared to controls, patients with psoriasis exhibited lower concentrations of serum TNF-α, IL-17, and FGL1 (P < 0.05). A correlation analysis showed that FGL1 was inversely correlated with high-density lipoprotein cholesterol and IL-17 in the psoriatic state. Stepwise multiple regression analysis revealed that FGL1 and total cholesterol were the independent determinants of Psoriasis Area and Severity Index (PASI) score in psoriasis patients. The area under the receiver operating characteristic curve of FGL1 assessing moderate-to-severe psoriasis and mild psoriasis was 0.70, while the area under the curve (AUC) assessing severe psoriasis and mild-to-moderate psoriasis was 0.67, better than that of IL-17. In addition, FGL1, but not IL-17, was able to identify psoriasis with abnormal lipid metabolism to a certain extent (AUC = 0.60).

Conclusion

In conclusion, serum FGL1 may be a promising biomarker for diagnosing and staging psoriasis. It may also be involved in its progression and comorbid abnormal lipid metabolism.

Metabolic Profile and Pathological Alterations in the Muscle of Patients with Early-Stage Amyotrophic Lateral Sclerosis

Diverse biomarkers and pathological alterations have been found in muscle of patients with Amyotrophic lateral sclerosis (ALS), but the relation between such alterations and dysfunction in energetic metabolism remains to be investigated. We established the metabolome of muscle and serum of ALS patients and correlated these findings with the clinical status and pathological alterations observed in the muscle. We obtained data from 20 controls and 17 ALS patients (disease duration: 9.4 ± 6.8 months). Multivariate metabolomics analysis identified a distinct serum metabolome for ALS compared to controls (p-CV-ANOVA < 0.035) and revealed an excellent discriminant profile for muscle metabolome (p-CV-ANOVA < 0.0012). Citramalate was discriminant for both muscle and serum. High lauroylcarnitine levels in muscle were associated with low Forced Vital Capacity. Transcriptomics analysis of key antioxidant enzymes showed an upregulation of SOD3 (p = 0.0017) and GLRX2(1) (p = 0.0022) in ALS muscle. Analysis of mitochondrial enzymatic activity in muscle revealed higher complex II/CS (p = 0.04) and lower LDH (p = 0.03) activity in ALS than in controls. Our study showed, for the first time, a global dysfunction in the muscle of early-stage ALS patients. Furthermore, we identified novel metabolites to be employed as biomarkers for diagnosis and prognosis of ALS patients.

Elevation of Serum Cytokine Profiles and Liver Metabolomic Normalization in Early Convalescence of COVID-19 Patients

Coronavirus disease 2019 (COVID-19) has become a global public health concern. We aimed to study the cytokine profile during the convalescent phase and its association with liver functions. We performed a retrospective study to investigate the longitudinal dynamic serum cytokine, liver function, and metabolomic profiles, as well as their potential correlations, from the viral replication phase to early convalescence. Our results demonstrated that liver injury was common. Liver injury was significantly associated with higher levels of interleukin (IL)-6 and IL-10 (p < 0.05). However, alanine aminotransferase levels decreased during the first week after hospital discharge (p < 0.01). In parallel, T-cell and B-cell immune response-stimulating cytokine IL-4, but not IL-2, was significantly elevated (p < 0.05). Furthermore, interferon-γ (IFN-γ) and tumor necrosis factor-α (TFN-α) levels increased, in contrast to the decrease in IL-6 and IL-10 levels; liver function returned to normal. The metabolomic analysis supported active recovery during early convalescence of COVID-19 patients that had distinct metabolic profiles associated with the hepatic tricarboxylic acid cycle, amino acid metabolism, and lipid metabolism. In addition, we identified a metabolomic association of IL-4 with liver repair. Our findings suggest that discharged patients continue to recover from the physiological effects of COVID-19, and the association of IL-4, IL-6, and IL-10 levels with metabolic changes and liver function repair may have important implications for clinical manifestations and treatment of COVID-19.

Interleukin-6 ablation does not alter morphofunctional heart characteristics but modulates physiological and inflammatory markers after strenuous exercise

Interleukin-6 (IL-6) is associated with pathological cardiac hypertrophy and can be dramatically increased in serum after an acute strenuous exercise session. However, IL-6 is also associated with the increased production and release of anti-inflammatory cytokines and the inhibition of tumor necrosis factor-alpha (TNF-α) after chronic moderate exercise. To elucidate the relevance of IL-6 in inflammatory and hypertrophic signaling in the heart in response to an acute strenuous exercise session, we combined transcriptome analysis using the BXD mice database and exercised IL-6 knockout mice (IL-6KO). Bioinformatic analysis demonstrated that low or high-levels of Il6 mRNA in the heart did not change the inflammation- and hypertrophy-related genes in BXD mice strains. On the other hand, bioinformatic analysis revealed a strong positive correlation between Il6 gene expression in skeletal muscle with inflammation-related genes in cardiac tissue in several BXD mouse strains, suggesting that skeletal muscle-derived IL-6 could alter the heart's intracellular signals, particularly the inflammatory signaling. As expected, an acute strenuous exercise session increased IL-6 levels in wild-type, but not in IL-6KO mice. Despite not showing morphofunctional differences in the heart at rest, the IL-6KO group presented a reduction in physical performance and attenuated IL-6, TNF-α, and IL-1beta kinetics in serum, as well as lower p38MAPK phosphorylation, Ampkalpha expression, and higher Acta1 and Tnf gene expressions in the left ventricle in the basal condition. In response to strenuous exercise, IL-6 ablation was linked to a reduction in the pro-inflammatory response and higher activation of classical physiological cardiac hypertrophy proteins.

BMP/TGF-β signaling as a modulator of neurodegeneration in ALS

This commentary focuses on the emerging intersection between BMP/TGF-β signaling roles in nervous system function and the amyotrophic lateral sclerosis (ALS) disease state. Future research is critical to elucidate the molecular underpinnings of this intersection of the cellular processes disrupted in ALS and those influenced by BMP/TGF-β signaling, including synapse structure, neurotransmission, plasticity, and neuroinflammation. Such knowledge promises to inform us of ideal entry points for the targeted modulation of dysfunctional cellular processes in an effort to abrogate ALS pathologies. It is likely that different interventions are required, either at discrete points in disease progression, or across multiple dysfunctional processes which together lead to motor neuron degeneration and death. We discuss the challenging, but intriguing idea that modulation of the pleiotropic nature of BMP/TGF-β signaling could be advantageous, as a way to simultaneously treat defects in more than one cell process across different forms of ALS.

Conditioned Medium from Cells Overexpressing TDP-43 Alters the Metabolome of Recipient Cells

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by the progressive death of both upper and lower motor neurons. The disease presents a poor prognosis, and patients usually die 2-5 years after the onset of symptoms. The hallmark of this disease is the presence of phosphorylated and ubiquitinated aggregates containing trans-active response DNA-binding protein-43 (TDP-43) in the cytoplasm of motor neurons. TDP-43 pathology has been associated with multiple pathways in ALS, such as metabolic dysfunction found in patients and in in vivo models. Recently, it has been described as a "prion-like" protein, as studies have shown its propagation in cell culture from ALS brain extract or overexpressed TDP-43 in co-culture and conditioned medium, resulting in cytotoxicity. However, the cellular alterations that are associated with this cytotoxicity require further investigation. Here, we investigated the effects of conditioned medium from HEK293T (Human Embryonic Kidney 293T) cells overexpressing TDP-43 on cellular morphology, proliferation, death, and metabolism. Although we did not find evidence of TDP-43 propagation, we observed a toxicity of TDP-43-conditioned medium and altered metabolism. These results, therefore, suggest (1) that cells overexpressing TDP-43 produce an extracellular environment that can perturb other cells and (2) that TDP-43 propagation alone may not be the only potentially cytotoxic cell-to-cell mechanism.

Understanding and managing metabolic dysfunction in Amyotrophic Lateral Sclerosis

INTRODUCTION

Amyotrophic Lateral Sclerosis (ALS) is a fatal motor neuron disease that leads to death after a median survival of 36 months. The development of an effective treatment has proven to be extremely difficult due to the inadequate understanding of the pathogenesis of ALS. Energy metabolism is thoroughly involved in the disease based on the discoveries of hypermetabolism, lipid/glucose metabolism, the tricarboxylic acid (TCA) cycle, and mitochondrial impairment.

AREA COVERED

Many perturbed metabolites within these processes have been identified as promising therapeutic targets. However, the therapeutic strategies targeting these pathways have failed to produce clinically significant results. The authors present in this review the metabolic disturbances observed in ALS and the derived-therapeutics.

EXPERT OPINION

The authors suggest that this is due to the insufficient knowledge of the relationship between the metabolic targets and the type of ALS of the patient, depending on genetic and environmental factors. We must improve our understanding of the pathological mechanisms and pay attention to the subtle hidden effects of changing diet, for example, and to use this strategy in addition to other drugs or to use metabolism status to determine subgroups of patients.

Immune dysregulation in amyotrophic lateral sclerosis: mechanisms and emerging therapies

Neuroinflammation is a common pathological feature of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), and is characterised by activated CNS microglia and astroglia, proinflammatory peripheral lymphocytes, and macrophages. Data from clinical studies show that multiple genetic mutations linked to ALS (eg, mutations in SOD1, TARDBP, and C9orf72) enhance this neuroinflammation, which provides compelling evidence for immune dysregulation in the pathogenesis of ALS. Transgenic rodent models expressing these mutations induce an ALS-like disease with accompanying inflammatory responses, confirming the immune system's involvement in disease progression. Even in the absence of known genetic alterations, immune dysregulation has been shown to lead to dysfunctional regulatory T lymphocytes and increased proinflammatory macrophages in clinical studies. Therefore, an improved understanding of the biological processes that induce this immune dysregulation will help to identify therapeutic strategies that circumvent or ameliorate the pathogenesis of ALS. Emerging cell-based therapies hold the promise of accomplishing this goal and, therefore, improving quality of life and extending survival in patients with ALS.

Integrated transcriptomic and metabolomic analyses to characterize the anti-cancer effects of (-)-epigallocatechin-3-gallate in human colon cancer cells

(-)-Epigallocatechin-3-gallate (EGCG) is the main bioactive component in tea (Camellia sinensis) catechins, and exhibits potential antitumor activity against colorectal cancer (CRC). However, the underlying mechanisms are largely unclear. We investigated the effects of EGCG on activities of CRC cells and the exact molecular mechanism. We used human colon cancer cells (HT-29) and exposed them to EGCG at various concentrations. The MTT assay, flow cytometry, and TUNEL staining were used to study the underlying mechanisms of EGCG (proliferation, apoptosis, autophagy). Western blotting was used to measure expression of marker proteins of the cell cycle, apoptosis, and autophagy. Using a combined microarray-based transcriptomic and ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (UHPLC-QTOF/MS)-based metabolomic approach, we investigated the perturbed pathways induced by EGCG treatment at transcript and metabolite levels. Transcriptomic analyses showed that 486 genes were differentially expressed between untreated and EGCG-treated cells. Also, 88 differentially expressed metabolites were identified between untreated and EGCG-treated cells. The altered metabolites were involved in the metabolism of glutathione, glycerophospholipids, starch, sucrose, amino sugars, and nucleotide sugars. There was substantial agreement between the results of transcriptomics and metabolomics analyses. Our data indicate that the anticancer activity of EGCG against HT-29 cells is mediated by induction of cell-cycle arrest, apoptosis, and autophagy. EGCG modulates cancer-cell metabolic pathways. These results provide a platform for future molecular mechanistic studies of EGCG.

Advances in cerebral palsy biomarkers

Cerebral palsy (CP), defined as a group of nonprogressive disorders of movement and posture, is the most common cause of severe neurodisability in children. The prevalence of CP is the same across the globe, affecting approximately 17 million people worldwide. Cerebral Palsy is an umbrella term used to describe the disease due to its inherent heterogeneity. For instance, CP has multiple (1) causes; (2) clinical types; (3) patterns of neuropathology on brain imaging and (4) it's associated with several developmental pathologies such as intellectual disability, autism, epilepsy, and visual impairment. Understanding its physiopathology is crucial to developing protective strategies. Despite its importance, there is still insufficient progress in the areas of CP prediction, early diagnosis, treatment, and prevention. Herein we describe the current risk factors and biomarkers used for the diagnosis and prediction of CP. With the advancement in biomarker discovery, we predict that our understanding of the etiopathophysiology of CP will also increase, lending to more opportunities for developing novel treatments and prognosis.

Metabolomics: A Tool to Understand the Impact of Genetic Mutations in Amyotrophic Lateral Sclerosis

Metabolomics studies performed in patients with amyotrophic lateral sclerosis (ALS) reveal a set of distinct metabolites that can shed light on the pathological alterations taking place in each individual. Metabolites levels are influenced by disease status, and genetics play an important role both in familial and sporadic ALS cases. Metabolomics analysis helps to unravel the differential impact of the most common ALS-linked genetic mutations (as C9ORF72, SOD1, TARDBP, and FUS) in specific signaling pathways. Further, studies performed in genetic models of ALS reinforce the role of TDP-43 pathology in the vast majority of ALS cases. Studies performed in differentiated cells from ALS-iPSC (induced Pluripotent Stem Cells) reveal alterations in the cell metabolism that are also found in ALS models and ultimately in ALS patients. The development of metabolomics approaches in iPSC derived from ALS patients allow addressing and ultimately understanding the pathological mechanisms taking place in any patient. Lately, the creation of a "patient in a dish" will help to identify patients that may benefit from specific treatments and allow the implementation of personalized medicine.

Transcriptomics and Metabolomics in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease involving progressive and selective loss of motor neurons, muscle weakness, paralysis and death. The pathogenesis of ALS is not clearly understood, while reliable prognostic markers have not been identified to detect symptoms at earlier time points. The rapid development of microarray technology offers great potential for simultaneous analysis of the transcriptional expression of thousands of genes, aiming to determine novel candidate targets for efficient treatment. Additionally, metabolomics, as a high-throughput approach, is gaining significant attention in ALS research providing an opportunity to develop predictive biomarkers that may be utilized as indicators of clinical symptoms of ALS. In this review, recent evidences from gene expression profiling studies in ALS are illustrated in order to examine molecular signatures related to the disease's pathogenesis and potential discovery of therapeutic targets. Moreover, potent challenges are presented regarding the utilization of the metabolomics approach as a diagnostic tool in context with distinctive biomarkers' identification.

TDP-43-Mediated Toxicity in HEK293T Cells: A Fast and Reproducible Protocol To Be Employed in the Search of New Therapeutic Options against Amyotrophic Lateral Sclerosis

Cytoplasmic TDP-43 aggregates are a hallmark of amyotrophic lateral sclerosis (ALS). Today, only two drugs are available for ALS treatment, and their modest effect prompts researchers to search for new therapeutic options. TDP-43 represents one of the most promising targets for therapeutic intervention, but reliable and reproducible in vitro protocols for TDP-43-mediated toxicity are lacking. Here, we used HEK293T cells transfected with increasing concentrations of TDP-43-expressing plasmid to evaluate different parameters of toxicity and alterations in cellular metabolism. Overexpression of TDP-43 induced aggregates occurrence followed by the detection of 25- and 35-kDa forms of TDP-43. TDP-43 overexpression decreased cell viability and increased cells arrested at G2/M phase and nuclear fragmentation. Analysis of the energetic metabolism showed a tendency to decrease oxidative phosphorylation and increase glycolysis, but no statistical differences were observed. Metabolomics revealed alterations in different metabolites (mainly sphingolipids and glycerophospholipids) in cells overexpressing TDP-43. Our data reveal the main role of TDP-43 aggregation in cellular death and highlight novel insight into the mechanism of cellular toxicity induced by TDP-43. Here, we provide a simple, sensitive, and reliable protocol in a human-derived cell line to be used in high-throughput screenings of potential therapeutic molecules for ALS treatment.

Hochu-Ekki-To Improves Motor Function in an Amyotrophic Lateral Sclerosis Animal Model

Hochu-ekki-to (Bojungikgi-Tang (BJIGT) in Korea; Bu-Zhong-Yi-Qi Tang in Chinese), a traditional herbal prescription, has been widely used in Asia. Hochu-ekki-to (HET) is used to enhance the immune system in respiratory disorders, improve the nutritional status associated with chronic diseases, enhance the mucosal immune system, and improve learning and memory. Amyotrophic lateral sclerosis (ALS) is pathologically characterized by motor neuron cell death and muscle paralysis, and is an adult-onset motor neuron disease. Several pathological mechanisms of ALS have been reported by clinical and in vitro/in vivo studies using ALS models. However, the underlying mechanisms remain elusive, and the critical pathological target needs to be identified before effective drugs can be developed for patients with ALS. Since ALS is a disease involving both motor neuron death and skeletal muscle paralysis, suitable therapy with optimal treatment effects would involve a motor neuron target combined with a skeletal muscle target. Herbal medicine is effective for complex diseases because it consists of multiple components for multiple targets. Therefore, we investigated the effect of the herbal medicine HET on motor function and survival in hSOD1^G93A transgenic mice. HET was orally administered once a day for 6 weeks from the age of 2 months (the pre-symptomatic stage) of hSOD1^G93A transgenic mice. We used the rota-rod test and foot printing test to examine motor activity, and Western blotting and H&E staining for evaluation of the effects of HET in the gastrocnemius muscle and lumbar (L4–5) spinal cord of mice. We found that HET treatment dramatically inhibited inflammation and oxidative stress both in the spinal cord and gastrocnemius of hSOD1^G93A transgenic mice. Furthermore, HET treatment improved motor function and extended the survival of hSOD1^G93A transgenic mice. Our findings suggest that HET treatment may modulate the immune reaction in muscles and neurons to delay disease progression in a model of ALS.

Metabolomics Coupled with Transcriptomics Approach Deciphering Age Relevance in Sepsis

Sepsis is a severe disease frequently occurred in the Intenisive Care Unit (ICU), which has a very high morbidity and mortality, especially in patients aged over 65 years. Owing to the aging effect and the ensuing deterioration of body function, the elder patients may have atypical responses to sepsis. Diagnosis and pathogenesis of sepsis in this population are thus difficult, which hindered effective treatment and management in clinic. To investigated age effects on sepsis, 158 elderly septic patients and 71 non-septic elderly participants were enrolled, and their plasma samples were collected for transcriptomics (RNA-seq) and metabolomics (NMR and GC-MS) analyses, which are both increasingly being utilized to discover key molecular changes and potential biomarkers for various diseases. Protein-protein interaction (PPI) analysis was subsequently performed to assist cross-platform integration. Real time polymerase chain reaction (RT-PCR) was used for validation of RNA-seq results. For further understanding of the mechanisms, cecal ligation and puncture (CLP) experiment was performed both in young and middle-aged rats, which were subjected to NMR-based metabolomics study and validated for several key inflammation pathways by western blot. Comprehensive analysis of data from the two omics approaches provides a systematic perspective on dysregulated pathways that could facilitate the development of therapy and biomarkers for elderly sepsis. Additionally, the metabolites of lactate, arginine, histamine, tyrosine, glutamate and glucose were shown to be highly specific and sensitive in distinguishing septic patients from healthy controls. Significant increases of arginine, trimethylamine N-oxide and allantoin characterized elderly patient incurred sepsis. Further analytical and biological validations in different subpopulations of septic patients should be carried out, allowing accurate diagnostics and precise treatment of sepsis in clinic.

The role of pro-inflammatory cytokines in lipid metabolism of metabolic diseases

Adipose tissue has been considered as a crucial source of certain pro-inflammatory cytokines; conversely, these pro-inflammatory cytokines are involved in regulating the proliferation and apoptosis of adipocytes, promoting lipolysis, inhibiting lipid synthesis and decreasing blood lipids, etc. In recent decades, extensive studies have indicated that pro-inflammatory cytokines play important roles in the development of lipid metabolism of metabolic diseases, including obesity, atherosclerosis, steatohepatitis and hyperlipoproteinemia. However, the involved pro-inflammatory cytokines types and the underlying mechanisms remain largely unknown. The "re-discovery" of cancer as a metabolic disorder largely occurred in the last five years. Although pro-inflammatory cytokines have been intensively investigated in cancer research, there are very few studies about the roles of pro-inflammatory cytokines in the lipid metabolism of cancer. In the current review, we provide an overview of the progress that has been made in the roles of different pro-inflammatory cytokines in lipid metabolism of metabolic diseases including cancer.

Astrocyte alterations in neurodegenerative pathologies and their modeling in human induced pluripotent stem cell platforms

Astrocytes are the most abundant cell type in the brain. They were long considered only as passive support for neuronal cells. However, recent data have revealed many active roles for these cells both in maintenance of the normal physiological homeostasis in the brain as well as in neurodegeneration and disease. Moreover, human astrocytes have been found to be much more complex than their rodent counterparts, and to date, astrocytes are known to actively participate in a multitude of processes such as neurotransmitter uptake and recycling, gliotransmitter release, neuroenergetics, inflammation, modulation of synaptic activity, ionic balance, maintenance of the blood-brain barrier, and many other crucial functions of the brain. This review focuses on the role of astrocytes in human neurodegenerative disease and the potential of the novel stem cell-based platforms in modeling astrocytic functions in health and in disease.

Are Circulating Cytokines Reliable Biomarkers for Amyotrophic Lateral Sclerosis?

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that has no effective treatment. The lack of any specific biomarker that can help in the diagnosis or prognosis of ALS has made the identification of biomarkers an urgent challenge. Multiple panels have shown alterations in levels of numerous cytokines in ALS, supporting the contribution of neuroinflammation to the progressive motor neuron loss. However, none of them is fully sensitive and specific enough to become a universal biomarker for ALS. This review gathers the numerous circulating cytokines that have been found dysregulated in both ALS animal models and patients. Particularly, it highlights the opposing results found in the literature to date, and points out another potential application of inflammatory cytokines as therapeutic targets.

Metabolic and Stress Response Changes Precede Disease Onset in the Spinal Cord of Mutant SOD1 ALS Mice

Many Amyotrophic Lateral Sclerosis (ALS) patients experience hypermetabolism, or an increase in measured vs. calculated metabolic rate. The cause of hypermetabolism and the effects on neuronal metabolism in ALS are currently unknown, but the efficacy of dietary interventions shows promise for metabolism as an ALS therapeutic target. The goal of this study is to measure changes in metabolic pathways as a function of disease progression in spinal cords of the SOD1^G93A mouse model of ALS. We conducted a comprehensive assessment of protein expression for metabolic pathways, antioxidants, chaperones, and proteases in lumbar spinal cord from male SOD1^G93A mice at pre-onset, onset, and end-stages of the disease using targeted proteomic analysis. These results reveal that protein content of metabolic proteins including proteins involved in glycolysis, β-oxidation, and mitochondrial metabolism is altered in SOD1^G93A mouse spinal cord well before disease onset. The changes in mitochondrial metabolism proteins are associated with decreased maximal respiration and glycolytic flux in SOD1^G93A dermal fibroblasts and increased hydrogen peroxide and lipid hydroperoxide production in mitochondria from sciatic nerve and gastrocnemius muscle fibers at end stage of disease. Consistent with redox dysregulation, expression of the glutathione antioxidant system is decreased, and peroxiredoxins and catalase expression are increased. In addition, stress response proteases and chaperones, including those involved in the mitochondrial unfolded protein response (UPR^mt), are induced before disease onset. In summary, we report that metabolic and stress response changes occur in SOD1^G93A lumbar spinal cord before motor symptom onset, and are primarily caused by SOD1^G93A expression and do not vary greatly as a function of disease course.

Inflammation, immunity, and amyotrophic lateral sclerosis: II. immune-modulating therapies

With the emerging popularity of immune-modulatory therapies to treat human diseases there is a need to step back from hypotheses aimed at assessing a condition in a single-system context and instead take into account the disease pathology as a whole. In complex diseases, such as amyotrophic lateral sclerosis (ALS), the use of these therapies to treat patients has been largely unsuccessful and likely premature given our lack of understanding of how the immune system influences disease progression and initiation. In addition, we still have an incomplete understanding of the role of these responses in our model systems and how this may translate clinically to human patients. In this review we discuss preclinical evidence and clinical trial results for a selection of recently conducted studies in ALS. We provide evidence-based reasoning for the failure of these trials and offer suggestions to improve the design of future investigations. Muscle Nerve 59:23-33, 2019.

The development of biological therapies for neurological diseases: moving on from previous failures

INTRODUCTION

Although years of research have expanded the use of biologics for several clinical conditions, such development has not yet occurred in the treatment of neurological diseases. With the advancement of biologic technologies, there is promise for these therapeutics as novel therapeutic approaches for neurological diseases. Areas covered: In this article, the authors review the therapeutic potential of different types of biologics for the treatment of neurological diseases. Preclinical and clinical studies that investigate the efficacy and safety of biologics in the treatment of neurological diseases, namely Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson disease, multiple sclerosis, and stroke, were reviewed. Moreover, the authors describe the key challenges in the development of therapeutically safe and effective biologics for the treatment of neurological diseases. Expert opinion: Several biologics have shown promise in the treatment of neurological diseases. However, the complexity of the CNS, as well as a limited understanding of disease progression, and restricted access of biologics to the CNS has limited successful development. Therefore, more research needs to be conducted to overcome these hurdles before developing effective and safe biologics for neurological diseases. The emergence of new technologies for the design, production and delivery of biologics will accelerate translating biologics to the clinic.

Potential Role of Humoral IL-6 Cytokine in Mediating Pro-Inflammatory Endothelial Cell Response in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a multifactorial disease with limited therapeutic options. Numerous intrinsic and extrinsic factors are involved in ALS motor neuron degeneration. One possible effector accelerating motor neuron death in ALS is damage to the blood-Central Nervous System barrier (B-CNS-B), mainly due to endothelial cell (EC) degeneration. Although mechanisms of EC damage in ALS are still unknown, vascular impairment may be initiated by various humoral inflammatory factors and other mediators. Systemic IL-6-mediated inflammation is a possible early extrinsic effector leading to the EC death causing central nervous system (CNS) barrier damage. In this review, we discuss the potential role of humoral factors in triggering EC alterations in ALS. A specific focus was on humoral IL-6 cytokine mediating EC inflammation via the trans-signaling pathway. Our preliminary in vitro studies demonstrated a proof of principle that short term exposure of human bone marrow endothelial cells to plasma from ALS patient leads to cell morphological changes, significantly upregulated IL-6R immunoexpression, and pro-inflammatory cell response. Our in-depth understanding of specific molecular mechanisms of this humoral cytokine in EC degeneration may facilitate an endothelial-IL-6-targeting therapy for restoring cell homeostasis and eventually reestablishing B-CNS-B integrity in ALS.

Sphingolipid Metabolism Is Dysregulated at Transcriptomic and Metabolic Levels in the Spinal Cord of an Animal Model of Amyotrophic Lateral Sclerosis

Lipid metabolism is drastically dysregulated in amyotrophic lateral sclerosis and impacts prognosis of patients. Animal models recapitulate alterations in the energy metabolism, including hypermetabolism and severe loss of adipose tissue. To gain insight into the molecular mechanisms underlying disease progression in amyotrophic lateral sclerosis, we have performed RNA-sequencing and lipidomic profiling in spinal cord of symptomatic SOD1^G86R mice. Spinal transcriptome of SOD1^G86R mice was characterized by differential expression of genes related to immune system, extracellular exosome, and lysosome. Hypothesis-driven identification of metabolites showed that lipids, including sphingomyelin(d18:0/26:1), ceramide(d18:1/22:0), and phosphatidylcholine(o-22:1/20:4) showed profound altered levels. A correlation between disease severity and gene expression or metabolite levels was found for sphingosine, ceramide(d18:1/26:0), Sgpp2, Sphk1, and Ugt8a. Joint-analysis revealed a significant enrichment of glycosphingolipid metabolism in SOD1^G86R mice, due to the down-regulation of ceramide, glucosylceramide, and lactosylceramide and the overexpression of genes involved in their recycling in the lysosome. A drug-gene interaction database was interrogated to identify potential drugs able to modulate the dysregulated genes from the signaling pathway. Our results suggest that complex lipids are pivotally changed during the first phase of motor symptoms in an animal model of amyotrophic lateral sclerosis.

The combination of four analytical methods to explore skeletal muscle metabolomics: Better coverage of metabolic pathways or a marketing argument?

OBJECTIVES

Metabolomics is an emerging science based on diverse high throughput methods that are rapidly evolving to improve metabolic coverage of biological fluids and tissues. Technical progress has led researchers to combine several analytical methods without reporting the impact on metabolic coverage of such a strategy. The objective of our study was to develop and validate several analytical techniques (mass spectrometry coupled to gas or liquid chromatography and nuclear magnetic resonance) for the metabolomic analysis of small muscle samples and evaluate the impact of combining methods for more exhaustive metabolite covering.

DESIGN AND METHODS

We evaluated the muscle metabolome from the same pool of mouse muscle samples after 2 metabolite extraction protocols. Four analytical methods were used: targeted flow injection analysis coupled with mass spectrometry (FIA-MS/MS), gas chromatography coupled with mass spectrometry (GC-MS), liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS), and nuclear magnetic resonance (NMR) analysis. We evaluated the global variability of each compound i.e., analytical (from quality controls) and extraction variability (from muscle extracts). We determined the best extraction method and we reported the common and distinct metabolites identified based on the number and identity of the compounds detected with low analytical variability (variation coefficient<30%) for each method. Finally, we assessed the coverage of muscle metabolic pathways obtained.

RESULTS

Methanol/chloroform/water and water/methanol were the best extraction solvent for muscle metabolome analysis by NMR and MS, respectively. We identified 38 metabolites by nuclear magnetic resonance, 37 by FIA-MS/MS, 18 by GC-MS, and 80 by LC-HRMS. The combination led us to identify a total of 132 metabolites with low variability partitioned into 58 metabolic pathways, such as amino acid, nitrogen, purine, and pyrimidine metabolism, and the citric acid cycle. This combination also showed that the contribution of GC-MS was low when used in combination with other mass spectrometry methods and nuclear magnetic resonance to explore muscle samples.

CONCLUSION

This study reports the validation of several analytical methods, based on nuclear magnetic resonance and several mass spectrometry methods, to explore the muscle metabolome from a small amount of tissue, comparable to that obtained during a clinical trial. The combination of several techniques may be relevant for the exploration of muscle metabolism, with acceptable analytical variability and overlap between methods However, the difficult and time-consuming data pre-processing, processing, and statistical analysis steps do not justify systematically combining analytical methods.

Wildtype motoneurons, ALS-Linked SOD1 mutation and glutamate profoundly modify astrocyte metabolism and lactate shuttling

The selective degeneration of motoneuron that typifies amyotrophic lateral sclerosis (ALS) implicates non-cell-autonomous effects of astrocytes. However, mechanisms underlying astrocyte-mediated neurotoxicity remain largely unknown. According to the determinant role of astrocyte metabolism in supporting neuronal function, we propose to explore the metabolic status of astrocytes exposed to ALS-associated conditions. We found a significant metabolic dysregulation including purine, pyrimidine, lysine, and glycerophospholipid metabolism pathways in astrocytes expressing an ALS-causing mutated superoxide dismutase-1 (SOD1) when co-cultured with motoneurons. SOD1 astrocytes exposed to glutamate revealed a significant modification of the astrocyte metabolic fingerprint. More importantly, we observed that SOD1 mutation and glutamate impact the cellular shuttling of lactate between astrocytes and motoneurons with a decreased in extra- and intra-cellular lactate levels in astrocytes. Based on the emergent strategy of metabolomics, this work provides novel insight for understanding metabolic dysfunction of astrocytes in ALS conditions and opens the perspective of therapeutics targets through focusing on these metabolic pathways. GLIA 2017 GLIA 2017;65:592-605.