TDP-43 aggregation induced by oxidative stress causes global mitochondrial imbalance in ALS

ALSUntangled #76: Wahls protocol

The Wahls diet is a modified Paleolithic diet that emphasizes dark green leafy vegetables, colorful fruits, high-quality animal proteins, and omega-3 polyunsaturated fatty acids, while limiting grains, legumes, dairy products, sugar, and processed foods containing proinflammatory omega-6 fatty acids. The Wahls diet may reduce inflammation, oxidative stress, and mitochondrial dysfunction and has plausible mechanisms for slowing amyotrophic lateral sclerosis (ALS) progression. However, research on its dietary components in the ALS animal models has yielded conflicting results. Though multiple cohort studies suggest high carotenoids, omega-3 fatty acids and fruit intake are associated with reduced ALS risks, neither the diet nor its components has been demonstrated to slow down ALS progression in case studies or clinical trials. On the contrary, the Wahls diet, a restrictive, low-carbohydrate and low glycemic index diet, caused an average weight loss of 7.2% BMI in multiple sclerosis clinical trials, which is a significant concern for people living with amyotrophic lateral sclerosis (PALS) as weight loss is associated with faster ALS progression and shorter survival. Considering the above, we cannot endorse the Wahls diet for slowing ALS progression.

TDP-43 transports ferritin heavy chain mRNA to regulate oxidative stress in neuronal axons

Amyotrophic lateral sclerosis (ALS) is characterized by the mislocalization and abnormal deposition of TAR DNA-binding protein 43 (TDP-43). This protein plays important roles in RNA metabolism and transport in motor neurons and glial cells. In addition, abnormal iron accumulation and oxidative stress are observed in the brain and spinal cord of patients with ALS exhibiting TDP-43 pathology and in animal models of ALS. We have previously demonstrated that TDP-43 downregulation significantly affects the expression of ferritin heavy chain (Fth1) mRNA in the axonal regions of neurons. Nevertheless, the mechanisms by which TDP-43 contributes to oxidative stress and iron accumulation in the central nervous system remain elusive. In this study, we aimed to investigate whether Fth1 mRNA is a target transported to the axon by TDP-43 using biophysical and biochemical analyses. Our results revealed Fth1 mRNA as a target mRNA transported to axons by TDP-43. Moreover, we demonstrated that TDP-43 regulates iron homeostasis and oxidative stress in neurons via Fth1 mRNA transport to the axons, possibly followed by a local translation of the ferritin heavy chain in the axons. This study suggests that TDP-43 plays an important role in preventing iron-mediated oxidative stress in neurons, with its loss contributing to ALS pathogenesis.

An overlap-weighted analysis on the association of constipation symptoms with disease progression and survival in amyotrophic lateral sclerosis: a nested case-control study

Background

Amyotrophic lateral sclerosis (ALS) is a rapidly progressing and rare neurodegenerative disease. Therefore, evaluating the risk factors affecting the survival of patients with ALS is crucial. Constipation, a common but overlooked symptom of ALS, can be effectively managed. It is currently unknown whether constipation contributes to the progression and survival of ALS.

Objectives

This study aimed to investigate the association between constipation and ALS development and survival using a novel overlap-weighted (OW) method to enhance the robustness and reliability of results.

Design

This prospective matching nested case-control (NCC) study was conducted within an ongoing ALS cohort at the Second Hospital of Hebei Medical University. Baseline data were collected from patients meeting the inclusion and exclusion criteria, with constipation as the exposure factor. A 9-month follow-up was conducted, with death as the endpoint event.

Methods

We primarily used the OW method in NCC studies to examine the association between constipation and ALS development and survival. Weighted Cox proportional hazards model was used to assess risk factors associated with overall survival. Survival differences between the two groups were analyzed using Kaplan-Meier's plots and log-rank tests. Finally, the bioinformatic analysis explored common pathways between ALS and constipation.

Results

Among the 190 patients included, the prevalence of constipation was 50%. Patients with ALS constipation exhibited faster disease progression (p < 0.001), with a positive correlation between constipation severity and progression rate (r = 0.356, p < 0.001). The constipation group had poorer survival before and after OW (log-rank test, p < 0.0001). In the Cox proportional hazards model of 114 patients, constipation was a risk factor for ALS both before (hazard ratio (HR) = 5.840, 95% confidence interval (CI) = 1.504-22.675, p = 0.011) and after (HR = 5.271, 95% CI = 1.241-22.379, p = 0.024) OW.

Conclusion

Constipation in individuals with ALS is associated with faster disease progression and reduced survival rates, potentially through the peroxisome proliferator-activated receptor pathway.

Targeting common disease pathomechanisms to treat amyotrophic lateral sclerosis

The motor neuron disease amyotrophic lateral sclerosis (ALS) is a devastating condition with limited treatment options. The past few years have witnessed a ramping up of translational ALS research, offering the prospect of disease-modifying therapies. Although breakthroughs using gene-targeted approaches have shown potential to treat patients with specific disease-causing mutations, the applicability of such therapies remains restricted to a minority of individuals. Therapies targeting more general mechanisms that underlie motor neuron pathology in ALS are therefore of considerable interest. ALS pathology is associated with disruption to a complex array of key cellular pathways, including RNA processing, proteostasis, metabolism and inflammation. This Review details attempts to restore cellular homeostasis by targeting these pathways in order to develop effective, broadly-applicable ALS therapeutics.

Isobicyclogermacrenal ameliorates hippocampal ferroptosis involvement in neurochemical disruptions and neuroinflammation induced by sleep deprivation in rats

BACKGROUND

Sleep deprivation (SLD) is a widespread condition that disrupts physiological functions and may increase mortality risk. Valeriana officinalis, a traditional medicinal herb known for its sedative and hypnotic properties, contains isobicyclogermacrenal (IG), a newly isolated active compound. However, research on the therapeutic potential of IG for treating SLD remains limited.

METHODS

In this study, IG was extracted and characterized from Valeriana officinalis, and an SLD model was established in rats using p-chlorophenylalanine (PCPA). Behavioral tests and pathological studies were conducted to assess the effects of IG on SLD, and transcriptomic and metabolomic analyses were utilized to investigate its underlying mechanisms.

RESULTS

IG administration significantly improved the cognitive performance of SLD rats in behavioral tests and ameliorated histological injuries in the hippocampus and cerebral cortex. IG treatment increased the levels of brain-derived neurotrophic factor (BDNF) and neurotransmitters such as serotonin (5-HT) in SLD rats. Additionally, IG directly targets TFRC, thereby improving iron metabolism in the hippocampus. Comprehensive transcriptomic and metabolomic analyses revealed that the improvements from IG stemmed from the mitigation of abnormalities in iron metabolism, cholesterol metabolism, and glutathione metabolism, leading to reduced oxidative stress, ferroptosis, and neuroinflammation in the hippocampus caused by SLD.

CONCLUSIONS

Collectively, these findings suggest that IG has the potential to ameliorate neurological damage and cognitive impairment caused by SLD, offering a novel strategy for protection against the adverse effects of SLD.

Predictive modeling of ALS progression: an XGBoost approach using clinical features

This research presents a predictive model aimed at estimating the progression of Amyotrophic Lateral Sclerosis (ALS) based on clinical features collected from a dataset of 50 patients. Important features included evaluations of speech, mobility, and respiratory function. We utilized an XGBoost regression model to forecast scores on the ALS Functional Rating Scale (ALSFRS-R), achieving a training mean squared error (MSE) of 0.1651 and a testing MSE of 0.0073, with R² values of 0.9800 for training and 0.9993 for testing. The model demonstrates high accuracy, providing a useful tool for clinicians to track disease progression and enhance patient management and treatment strategies.

The nitrone compound OKN-007 delays motor neuron loss and disease progression in the G93A mouse model of amyotrophic lateral sclerosis

Our study investigated the therapeutic potential of OKN-007 in the SOD1 G93A mouse model of amyotrophic lateral sclerosis (ALS). The impact of OKN-007, known for its antioxidant, anti-inflammatory, and neuroprotective properties, was tested at two doses (150 mg/kg and 300 mg/kg) at onset and late-stage disease. Results demonstrated a significant delay in disease progression at both doses, with treated mice showing a slower advance to early disease stages compared to untreated controls. Motor neuron counts in the lumbar spinal cord were notably higher in OKN-007 treated mice at the time of disease onset, suggesting neuroprotection. Additionally, OKN-007 reduced microglial activation and preserved reduced neuromuscular junction fragmentation, although it did not significantly alter the increase in astrocyte number or the decline in hindlimb muscle mass. MR spectroscopy (MRS) revealed improved spinal cord perfusion and normalized myo-inositol levels in treated mice, supporting reduced neuroinflammation. While the expression of several proteins associated with inflammation is increased in spinal cord extracts from G93A mice, OKN-007 dampened the expression of IL-1β, IL-1ra and IL-1α. Despite its promising effects on early-stage disease progression, in general, the beneficial effects of OKN-007 diminished over longer treatment durations. Further, we found no improvement in muscle atrophy or weakness phenotypes in OKN-007 treated G93A mice, and no effect on mitochondrial function or lifespan. Overall, our findings suggest that OKN-007 holds potential as a disease-modifying treatment for ALS, although further research is needed to optimize dosing regimens and understand its long-term effects.

Co-Aggregation of TDP-43 with Other Pathogenic Proteins and Their Co-Pathologies in Neurodegenerative Diseases

Pathological aggregation of a specific protein into insoluble aggregates is a common hallmark of various neurodegenerative diseases (NDDs). In the earlier literature, each NDD is characterized by the aggregation of one or two pathogenic proteins, which can serve as disease-specific biomarkers. The aggregation of these specific proteins is thought to be a major cause of or deleterious result in most NDDs. However, accumulating evidence shows that a pathogenic protein can interact and co-aggregate with other pathogenic proteins in different NDDs, thereby contributing to disease onset and progression synergistically. During the past years, more than one type of NDD has been found to co-exist in some individuals, which may increase the complexity and pathogenicity of these diseases. This article reviews and discusses the biochemical characteristics and molecular mechanisms underlying the co-aggregation and co-pathologies associated with TDP-43 pathology. The TDP-43 aggregates, as a hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), can often be detected in other NDDs, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and spinocerebellar ataxia type 2 (SCA2). In many cases, TDP-43 is shown to interact and co-aggregate with multiple pathogenic proteins in vitro and in vivo. Furthermore, the co-occurrence and co-aggregation of TDP-43 with other pathogenic proteins have important consequences that may aggravate the diseases. Thus, the current viewpoint that the co-aggregation of TDP-43 with other pathogenic proteins in NDDs and their relevance to disease progression may gain insights into the patho-mechanisms and therapeutic potential of various NDDs.

The Scientific and Therapeutic Rationale for Off-Label Treatments in Amyotrophic Lateral Sclerosis

There are no dramatically effective pharmacological treatments for most patients with amyotrophic lateral sclerosis, a complex disease with multiple underlying mechanisms, such as neuroinflammation, oxidative stress, mitochondrial dysfunction, microbiome alteration, and antiretroviral activity. We sifted through 15 years of reviews by a group called ALSUntangled to identify 8 alternative and off-label treatments that target ≥1 of these mechanisms, and have ≥1 human trial suggesting meaningful benefits. Given the overlapping pathological mechanisms of the highlighted products, we suggest that combinations of these treatments targeting diverse mechanisms might be worthwhile for future amyotrophic lateral sclerosis therapy development. ANN NEUROL 2024.

BS-clock, advancing epigenetic age prediction with high-resolution DNA methylation bisulfite sequencing data

MOTIVATION

DNA methylation patterns provide precise and accurate estimates of biological age due to their robustness and predictable changes associated with aging processes. Although several methylation aging clocks have been developed in recent years, they are primarily designed for DNA methylation array data, which has limited CpG coverage and detection sensitivity compared to bisulfite sequencing data.

RESULTS

Here, we present BS-clock, a novel DNA methylation clock for human aging based on bisulfite sequencing data. Using BS-seq data from 529 samples retrieved from four tissues, our BS-clock achieves higher correlations with chronological age in multiple tissue types compared to existing array-based clocks. Our study revealed age-dependent aging rates across different age stages and disease conditions, and overall low cross-tissue prediction capability by applying the model trained on one tissue type to others. In summary, BS-clock overcomes limitations of array-based techniques, offering genome-wide CpG site coverage and more robust and accurate aging quantification. This research paves the way for advanced epigenetic studies of aging and holds promise for developing targeted interventions to promote healthy aging.

AVAILABILITY AND IMPLEMENTATION

All analysis codes for reproducing the results of the study are publicly available at https://github.com/hucongcong97/BS-clock.

Decreased antioxidant-related superoxide dismutase 1 expression in peripheral immune cells indicates early ethanol exposure

Alcohol consumption increases oxidative stress and imbalances in the antioxidant system, even with ethanol (EtOH) exposure at a young age. This study assessed changes in the antioxidant system following young EtOH exposure in peripheral immunity and measured sensitive indicators of heavy alcohol consumption. We used peripheral blood mononuclear cells (PBMCs) from 197 male university students without smoking habits to examine changes in antioxidant-related gene expression in vitro and in PBMCs. In vitro, the antioxidant system was impaired by EtOH. Next, we examined the expression of 84 antioxidant-related genes in the PBMCs of 162 young adults, among which the superoxide dismutase (SOD) 1 expression was most negatively correlated with alcohol consumption degree. The plasma SOD1 level had the highest area under the curve value (0.806) for heavy alcohol consumption. Our data demonstrated that a decreased SOD1 level is a sensitive indicator of an impaired antioxidant system and heavy alcohol consumption with early EtOH exposure.

Nasal instillation of polystyrene nanoplastics induce lung injury via mitochondrial DNA release and activation of the cyclic GMP-AMP synthase-stimulator of interferon genes-signaling cascade

Nanoplastics (NPs) are a common type of degraded plastic material associated with adverse health effects such as pulmonary injury. However, the molecular mechanism(s) underlying lung injury as caused by NPs remains uncertain. Thus, we herein investigated the pulmonary toxicity of NPs on RAW264.7 cells and C57BL/6 mice. Our in vitro study indicated that NPs induced oxidative stress, cell death, inflammation, and the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-signaling pathway. Mice in our in vivo study displayed significant pulmonary fibrosis, inflammation, apoptosis, necrosis, and excessive double-stranded DNA release into serum and bronchoalveolar lavage fluid. Our mechanistic exploration uncovered cGAS-STING-signaling activation as the leading cause of NPs-induced pulmonary fibrosis. The current study opens an avenue toward elucidating the role of the cGAS-STING-signaling pathway in NPs-induced pulmonary injury.

Advancements in Pharmacological Interventions and Novel Therapeutic Approaches for Amyotrophic Lateral Sclerosis

(1) Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease in which the patient suffers from an affection of both upper and lower motor neurons at the spinal and brainstem level, causing a progressive paralysis that leads to the patient's demise. Gender is also considered a predisposing risk factor for developing the disease. A brief review of the pathophysiological mechanisms of the disease is also described in this work. Despite the fact that a cure for ALS is currently unknown, there exists a variety of pharmacological and non-pharmacological therapies that can help reduce the progression of the disease over a certain period of time and alleviate symptoms. (2) We aim to analyze these pharmacological and non-pharmacological therapies through a systematic review. A comprehensive, multidisciplinary approach to treatment is necessary. (3) Drugs such as riluzole, edaravone, and sodium phenylbutyrate, among others, have been investigated. Additionally, it is important to stay updated on research on new drugs, such as masitinib, from which very good results have been obtained. (4) Therapies aimed at psychological support, speech and language, and physical therapy for the patient are also available, which increase the quality of life of the patients.

Expression Changes of miRNAs in Humans and Animal Models of Amyotrophic Lateral Sclerosis and Their Potential Application for Clinical Diagnosis

Amyotrophic lateral sclerosis (ALS) is a severe motor neuron disease. Current detection methods can only confirm the diagnosis at the onset of the disease, missing the critical window for early treatment. Recent studies using animal models have found that detecting changes in miRNA sites can predict the onset and severity of the disease in its early stages, facilitating early diagnosis and treatment. miRNAs show expression changes in motor neurons that connect the brain, spinal cord, and brain stem, as well as in the skeletal muscle in mouse models of ALS. Clinically, expression changes in some miRNAs in patients align with those in mouse models, such as the upregulation of miR-29b in the brain and the upregulation of miR-206 in the skeletal muscle. This study provides an overview of some miRNA study findings in humans as well as in animal models, including SOD1, FUS, TDP-43, and C9orf72 transgenic mice and wobbler mice, highlighting the potential of miRNAs as diagnostic markers for ALS. miR-21 and miR-206 are aberrantly expressed in both mouse model and patient samples, positioning them as key potential diagnostic markers in ALS. Additionally, miR-29a, miR-29b, miR-181a, and miR-142-3p have shown aberrant expression in both types of samples and show promise as clinical targets for ALS. Finally, miR-1197 and miR-486b-5p have been recently identified as aberrantly expressed miRNAs in mouse models for ALS, although further studies are needed to determine their viability as diagnostic targets.

The role of ALDH2 rs671 polymorphism and C-reactive protein in the phenotypes of male ALS patients

Background

The aldehyde dehydrogenase 2 (ALDH2) rs671 (A) allele has been implicated in neurodegeneration, potentially through oxidative and inflammatory pathways. The study aims to investigate the effects of the ALDH2 rs671 (A) allele and high sensitivity C-reactive protein (hs-CRP) on the clinical phenotypes of amyotrophic lateral sclerosis (ALS) in male and female patients.

Methods

Clinical data and ALDH2 rs671 genotype of 143 ALS patients, including 85 males and 58 females, were collected from January 2018 to December 2022. All patients underwent assessment using the Chinese version of the Edinburgh Cognitive and Behavioral ALS Screen (ECAS). Complete blood count and metabolic profiles were measured. Clinical and laboratory parameters were compared between carriers and non-carriers of the rs671 (A) allele in males and females, respectively. The significant parameters and rs671 (A) Allele were included in multivariate linear regression models to identify potential contributors to motor and cognitive impairment. Mediation analysis was employed to evaluate any mediation effects.

Results

Male patients carrying rs671 (A) allele exhibited higher levels of hs-CRP than non-carriers (1.70 mg/L vs. 0.50 mg/L, p = 0.006). The rs671 (A) allele was identified as an independent risk factor for faster disease progression only in male patients (β = 0.274, 95% CI = 0.048-0.499, p = 0.018). The effect of the rs671 (A) allele on the executive function in male patients was fully mediated by hs-CRP (Indirect effect = -1.790, 95% CI = -4.555--0.225). No effects of the rs671 (A) allele or hs-CRP were observed in female ALS patients. The effects of the ALDH2 rs671 (A) allele and the mediating role of hs-CRP in male patients remained significant in the sensitivity analyses.

Conclusion

The ALDH2 rs671 (A) allele contributed to faster disease progression and hs-CRP mediated cognitive impairment in male ALS patients.

Polystyrene nanoparticles trigger aberrant condensation of TDP-43 and amyotrophic lateral sclerosis-like symptoms

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the dysfunction and progressive death of cerebral and spinal motor neurons. Preliminary epidemiological research has hinted at a relationship between environmental risks and the escalation of ALS, but the underlying reasons remain mostly mysterious. Here we show that nanosize polystyrene plastics (PS) induce ALS-like symptoms and illustrate the related molecular mechanism. When exposed to PS, cells endure internal oxidative stress, which leads to the aggregation of TAR DNA-binding protein 43 kDa (TDP-43), triggering ALS-like characteristics. In addition, the oxidized heat shock protein 70 fails to escort TDP-43 back to the nucleus. The cytoplasmic accumulation of TDP-43 facilitates the formation of a complex between PS and TDP-43, enhancing the condensation and solidification of TDP-43. These findings are corroborated through in silico and in vivo assays. Altogether, our work illustrates a unique toxicological mechanism induced by nanoparticles and provides insights into the connection between environmental pollution and neurodegenerative disorders.

CHCHD2 P14L, found in amyotrophic lateral sclerosis, exhibits cytoplasmic mislocalization and alters Ca2+ homeostasis

CHCHD2 and CHCHD10, linked to Parkinson's disease and amyotrophic lateral sclerosis-frontotemporal dementia (ALS), respectively, are mitochondrial intermembrane proteins that form a heterodimer. This study aimed to investigate the impact of the CHCHD2 P14L variant, implicated in ALS, on mitochondrial function and its subsequent effects on cellular homeostasis. The missense variant of CHCHD2, P14L, found in a cohort of patients with ALS, mislocalized CHCHD2 to the cytoplasm, leaving CHCHD10 in the mitochondria. Drosophila lacking the CHCHD2 ortholog exhibited mitochondrial degeneration. In contrast, human CHCHD2 P14L, but not wild-type human CHCHD2, failed to suppress this degeneration, suggesting that P14L is a pathogenic variant. The mitochondrial Ca2+ buffering capacity was reduced in Drosophila neurons expressing human CHCHD2 P14L. The altered Ca2+-buffering phenotype was also observed in cultured human neuroblastoma SH-SY5Y cells expressing CHCHD2 P14L. In these cells, transient elevation of cytoplasmic Ca2+ facilitated the activation of calpain and caspase-3, accompanied by the processing and insolubilization of TDP-43. These observations suggest that CHCHD2 P14L causes abnormal Ca2+ dynamics and TDP-43 aggregation, reflecting the pathophysiology of ALS.

Composite Hydrogel Containing Collagen-Modified Polylactic Acid-Hydroxylactic Acid Copolymer Microspheres Loaded with Tetramethylpyrazine Promotes Articular Cartilage Repair

Articular cartilage defects pose a significant challenge due to the limited self-healing ability of cartilage. However, traditional techniques face limitations including autologous chondrocyte expansion issues. This study aims to investigate the effects of the polylactic acid-glycolic acid (PLGA) and collagen-surface modified polylactic acid-glycolic acid (CPLGA) microspheres loaded with tetramethylpyrazine (TMP) on two cell types and the regeneration potential of articular cartilage. CPLGA microspheres are prepared by Steglich reaction and characterized. They evaluated the effect of TMP-loaded microspheres on HUVECs (Human Umbilical Vein Endothelial Cells) and examined the compatibility of blank microspheres with BMSCs (Bone marrow mesenchymal stromal cells) and their potential to promote cartilage differentiation. Subcutaneous implant immune tests and cartilage defect treatment are conducted to assess biocompatibility and cartilage repair potential. The results highlight the efficacy of CPLGA microspheres in promoting tissue regeneration, attributed to improved hydrophilicity and collagen-induced mitigation of degradation. Under hypoxic conditions, both CPLGA and PLGA TMP-loaded microspheres exhibit inhibitory effects on HUVEC proliferation, migration, and angiogenesis. Notably, CPLGA microspheres show enhanced compatibility with BMSCs, facilitating chondrogenic differentiation. Moreover, the CPLGA microsphere-composite hydrogel exhibits potential for cartilage repair by modulating angiogenesis and promoting BMSC differentiation.

Aberrant protein aggregation in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal disease. As its pathological mechanisms are not well understood, there are no efficient therapeutics for it at present. While it is highly heterogenous both etiologically and clinically, it has a common salient hallmark, i.e., aberrant protein aggregation (APA). The upstream pathogenesis and the downstream effects of APA in ALS are sophisticated and the investigation of this pathology would be of consequence for understanding ALS. In this paper, the pathomechanism of APA in ALS and the candidate treatment strategies for it are discussed.

Ergothioneine promotes longevity and healthy aging in male mice

Healthy aging has emerged as a crucial issue with the increase in the geriatric population worldwide. Food-derived sulfur-containing amino acid ergothioneine (ERGO) is a potential dietary supplement, which exhibits various beneficial effects in experimental animals although the preventive effects of ERGO on aging and/or age-related impairments such as frailty and cognitive impairment are unclear. We investigated the effects of daily oral supplementation of ERGO dissolved in drinking water on lifespan, frailty, and cognitive impairment in male mice from 7 weeks of age to the end of their lives. Ingestion of 4 ~ 5 mg/kg/day of ERGO remarkably extended the lifespan of male mice. The longevity effect of ERGO was further supported by increase in life and non-frailty spans of Caenorhabditis elegans in the presence of ERGO. Compared with the control group, the ERGO group showed significantly lower age-related declines in weight, fat mass, and average and maximum movement velocities at 88 weeks of age. This was compatible with dramatical suppression by ERGO of the age-related increments in plasma biomarkers (BMs) such as the chemokine ligand 9, creatinine, symmetric dimethylarginine, urea, asymmetric dimethylarginine, quinolinic acid, and kynurenine. The oral intake of ERGO also rescued age-related impairments in learning and memory ability, which might be associated with suppression of the age-related decline in hippocampal neurogenesis and TDP43 protein aggregation and promotion of microglial shift to the M2 phenotype by ERGO ingestion. Ingestion of ERGO may promote longevity and healthy aging in male mice, possibly through multiple biological mechanisms.

Guggulsterone Selectively Modulates STAT-3, mTOR, and PPAR-Gamma Signaling in a Methylmercury-Exposed Experimental Neurotoxicity: Evidence from CSF, Blood Plasma, and Brain Samples

Amyotrophic lateral sclerosis (ALS) is a paralytic disease that damages the brain and spinal cord motor neurons. Several clinical and preclinical studies have found that methylmercury (MeHg+) causes ALS. In ALS, MeHg+-induced neurotoxicity manifests as oligodendrocyte destruction; myelin basic protein (MBP) deficiency leads to axonal death. ALS development has been connected to an increase in signal transducer and activator of transcription-3 (STAT-3), a mammalian target of rapamycin (mTOR), and a decrease in peroxisome proliferator-activated receptor (PPAR)-gamma. Guggulsterone (GST), a plant-derived chemical produced from Commiphorawhighitii resin, has been found to protect against ALS by modulating these signaling pathways. Vitamin D3 (VitD3) deficiency has been related to oligodendrocyte precursor cells (OPC) damage, demyelination, and white matter deterioration, which results in motor neuron death. As a result, the primary goal of this work was to investigate the therapeutic potential of GST by altering STAT-3, mTOR, and PPAR-gamma levels in a MeHg+-exposed experimental model of ALS in adult rats. The GST30 and 60 mg/kg oral treatments significantly improved the behavioral, motor, and cognitive dysfunctions and increased remyelination, as proven by the Luxol Fast Blue stain (LFB), and reduced neuroinflammation as measured by histological examinations. Furthermore, the co-administration of VitD3 exhibits moderate efficacy when administered in combination with GST60. Our results show that GST protects neurons by decreasing STAT-3 and mTOR levels while increasing PPAR-gamma protein levels in ALS rats.

Circulating proteomic biomarkers for diagnosing sporadic amyotrophic lateral sclerosis: a cross-sectional study

JOURNAL/nrgr/04.03/01300535-202408000-00039/figure1/v/2023-12-16T180322Z/r/image-tiff Biomarkers are required for the early detection, prognosis prediction, and monitoring of amyotrophic lateral sclerosis, a progressive disease. Proteomics is an unbiased and quantitative method that can be used to detect neurochemical signatures to aid in the identification of candidate biomarkers. In this study, we used a label-free quantitative proteomics approach to screen for substantially differentially regulated proteins in ten patients with sporadic amyotrophic lateral sclerosis compared with five healthy controls. Substantial upregulation of serum proteins related to multiple functional clusters was observed in patients with sporadic amyotrophic lateral sclerosis. Potential biomarkers were selected based on functionality and expression specificity. To validate the proteomics profiles, blood samples from an additional cohort comprising 100 patients with sporadic amyotrophic lateral sclerosis and 100 healthy controls were subjected to enzyme-linked immunosorbent assay. Eight substantially upregulated serum proteins in patients with sporadic amyotrophic lateral sclerosis were selected, of which the cathelicidin-related antimicrobial peptide demonstrated the best discriminative ability between patients with sporadic amyotrophic lateral sclerosis and healthy controls (area under the curve [AUC] = 0.713, P < 0.0001). To further enhance diagnostic accuracy, a multi-protein combined discriminant algorithm was developed incorporating five proteins (hemoglobin beta, cathelicidin-related antimicrobial peptide, talin-1, zyxin, and translationally-controlled tumor protein). The algorithm achieved an AUC of 0.811 and a P-value of < 0.0001, resulting in 79% sensitivity and 71% specificity for the diagnosis of sporadic amyotrophic lateral sclerosis. Subsequently, the ability of candidate biomarkers to discriminate between early-stage amyotrophic lateral sclerosis patients and controls, as well as patients with different disease severities, was examined. A two-protein panel comprising talin-1 and translationally-controlled tumor protein effectively distinguished early-stage amyotrophic lateral sclerosis patients from controls (AUC = 0.766, P < 0.0001). Moreover, the expression of three proteins (FK506 binding protein 1A, cathelicidin-related antimicrobial peptide, and hemoglobin beta-1) was found to increase with disease progression. The proteomic signatures developed in this study may help facilitate early diagnosis and monitor the progression of sporadic amyotrophic lateral sclerosis when used in combination with current clinical-based parameters.

Senataxin deficiency disrupts proteostasis through nucleolar ncRNA-driven protein aggregation

Senataxin is an evolutionarily conserved RNA-DNA helicase involved in DNA repair and transcription termination that is associated with human neurodegenerative disorders. Here, we investigated whether Senataxin loss affects protein homeostasis based on previous work showing R-loop-driven accumulation of DNA damage and protein aggregates in human cells. We find that Senataxin loss results in the accumulation of insoluble proteins, including many factors known to be prone to aggregation in neurodegenerative disorders. These aggregates are located primarily in the nucleolus and are promoted by upregulation of non-coding RNAs expressed from the intergenic spacer region of ribosomal DNA. We also map sites of R-loop accumulation in human cells lacking Senataxin and find higher RNA-DNA hybrids within the ribosomal DNA, peri-centromeric regions, and other intergenic sites but not at annotated protein-coding genes. These findings indicate that Senataxin loss affects the solubility of the proteome through the regulation of transcription-dependent lesions in the nucleus and the nucleolus.

Hetero-oligomerization of TDP-43 carboxy-terminal fragments with cellular proteins contributes to proteotoxicity

Carboxy terminal fragments (CTFs) of TDP-43 contain an intrinsically disordered region (IDR) and form cytoplasmic condensates containing amyloid fibrils. Such condensates are toxic and associated with pathogenicity in amyotrophic lateral sclerosis. However, the molecular details of how the domain of TDP-43 CTFs leads to condensation and cytotoxicity remain elusive. Here, we show that truncated RNA/DNA-recognition motif (RRM) at the N-terminus of TDP-43 CTFs leads to the structural transition of the IDR, whereas the IDR itself of TDP-43 CTFs is difficult to assemble even if they are proximate intermolecularly. Hetero-oligomers of TDP-43 CTFs that have recruited other proteins are more toxic than homo-oligomers, implicating loss-of-function of the endogenous proteins by such oligomers is associated with cytotoxicity. Furthermore, such toxicity of TDP-43 CTFs was cell-nonautonomously affected in the nematodes. Therefore, misfolding and oligomeric characteristics of the truncated RRM at the N-terminus of TDP-43 CTFs define their condensation properties and toxicity.

Protein aggregation and therapeutic strategies in SOD1- and TDP-43- linked ALS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with severe socio-economic impact. A hallmark of ALS pathology is the presence of aberrant cytoplasmic inclusions composed of misfolded and aggregated proteins, including both wild-type and mutant forms. This review highlights the critical role of misfolded protein species in ALS pathogenesis, particularly focusing on Cu/Zn superoxide dismutase (SOD1) and TAR DNA-binding protein 43 (TDP-43), and emphasizes the urgent need for innovative therapeutic strategies targeting these misfolded proteins directly. Despite significant advancements in understanding ALS mechanisms, the disease remains incurable, with current treatments offering limited clinical benefits. Through a comprehensive analysis, the review focuses on the direct modulation of the misfolded proteins and presents recent discoveries in small molecules and peptides that inhibit SOD1 and TDP-43 aggregation, underscoring their potential as effective treatments to modify disease progression and improve clinical outcomes.

RNP granules in ALS and neurodegeneration: From multifunctional membraneless organelles to therapeutic opportunities

Amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases are characterised by dysfunction of a host of RNA-binding proteins (RBPs) and a severely disrupted RNA metabolism. Recently, RBP-harbouring phase-separated complexes, ribonucleoprotein (RNP) granules, have come into the limelight as "crucibles" of neuronal pathology in ALS. RNP granules are indispensable for the multitude of regulatory processes underlying cellular RNA metabolism and serve as critical organisers of cellular biochemistry. Neurons, highly specialised cells, heavily rely on RNP granules for efficient trafficking, signalling and stress responses. Multiple RNP granule components, primarily RBPs such as TDP-43 and FUS, are affected by ALS mutations. However, even in the absence of mutations, RBP proteinopathies represent pathophysiological hallmarks of ALS. Given the high local concentrations of RBPs and RNAs, their weakened or enhanced interactions within RNP granules disrupt their homeostasis. Thus, the physiological process of phase separation and RNP granule formation, vital for maintaining the high-functioning state of neuronal cells, becomes their Achilles heel. Here, we will review the recent literature on the causes and consequences of abnormal RNP granule functioning in ALS and related disorders. In particular, we will summarise the evidence for the network-level dysfunction of RNP granules in these conditions and discuss considerations for therapeutic interventions to target RBPs, RNP granules and their network as a whole.

Drug Screening and Validation Targeting TDP-43 Proteinopathy for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) stands as a rare, yet severely debilitating disorder marked by the deterioration of motor neurons (MNs) within the brain and spinal cord, which is accompanied by degenerated corticobulbar/corticospinal tracts and denervation in skeletal muscles. Despite ongoing research efforts, ALS remains incurable, attributed to its intricate pathogenic mechanisms. A notable feature in the pathology of ALS is the prevalence of TAR DNA-binding protein 43 (TDP-43) proteinopathy, detected in approximately 97% of ALS cases, underscoring its significance in the disease's progression. As a result, strategies targeting the aberrant TDP-43 protein have garnered attention as a potential avenue for ALS therapy. This review delves into the existing drug screening systems aimed at TDP-43 proteinopathy and the models employed for drug efficacy validation. It also explores the hurdles encountered in the quest to develop potent medications against TDP-43 proteinopathy, offering insights into the intricacies of drug discovery and development for ALS. Through this comprehensive analysis, the review sheds light on the critical aspects of identifying and advancing therapeutic solutions for ALS.

L-Carnitine in the Treatment of Psychiatric and Neurological Manifestations: A Systematic Review

OBJECTIVE

L-carnitine (LC), a vital nutritional supplement, plays a crucial role in myocardial health and exhibits significant cardioprotective effects. LC, being the principal constituent of clinical-grade supplements, finds extensive application in the recovery and treatment of diverse cardiovascular and cerebrovascular disorders. However, controversies persist regarding the utilization of LC in nervous system diseases, with varying effects observed across numerous mental and neurological disorders. This article primarily aims to gather and analyze database information to comprehensively summarize the therapeutic potential of LC in patients suffering from nervous system diseases while providing valuable references for further research.

METHODS

A comprehensive search was conducted in PubMed, Web Of Science, Embase, Ovid Medline, Cochrane Library and Clinicaltrials.gov databases. The literature pertaining to the impact of LC supplementation on neurological or psychiatric disorders in patients was reviewed up until November 2023. No language or temporal restrictions were imposed on the search.

RESULTS

A total of 1479 articles were retrieved, and after the removal of duplicates through both automated and manual exclusion processes, 962 articles remained. Subsequently, a meticulous re-screening led to the identification of 60 relevant articles. Among these, there were 12 publications focusing on hepatic encephalopathy (HE), while neurodegenerative diseases (NDs) and peripheral nervous system diseases (PNSDs) were represented by 9 and 6 articles, respectively. Additionally, stroke was addressed in five publications, whereas Raynaud's syndrome (RS) and cognitive disorder (CD) each had three dedicated studies. Furthermore, migraine, depression, and amyotrophic lateral sclerosis (ALS) each accounted for two publications. Lastly, one article was found for other symptoms under investigation.

CONCLUSION

In summary, LC has demonstrated favorable therapeutic effects in the management of HE, Alzheimer's disease (AD), carpal tunnel syndrome (CTS), CD, migraine, neurofibromatosis (NF), PNSDs, RS, and stroke. However, its efficacy appears to be relatively limited in conditions such as ALS, ataxia, attention deficit hyperactivity disorder (ADHD), depression, chronic fatigue syndrome (CFS), Down syndrome (DS), and sciatica.

AGO2 Protects Against Diabetic Cardiomyopathy by Activating Mitochondrial Gene Translation

BACKGROUND

Diabetes is associated with cardiovascular complications. microRNAs translocate into subcellular organelles to modify genes involved in diabetic cardiomyopathy. However, functional properties of subcellular AGO2 (Argonaute2), a core member of miRNA machinery, remain elusive.

METHODS

We elucidated the function and mechanism of subcellular localized AGO2 on mouse models for diabetes and diabetic cardiomyopathy. Recombinant adeno-associated virus type 9 was used to deliver AGO2 to mice through the tail vein. Cardiac structure and functions were assessed by echocardiography and catheter manometer system.

RESULTS

AGO2 was decreased in mitochondria of diabetic cardiomyocytes. Overexpression of mitochondrial AGO2 attenuated diabetes-induced cardiac dysfunction. AGO2 recruited TUFM, a mitochondria translation elongation factor, to activate translation of electron transport chain subunits and decrease reactive oxygen species. Malonylation, a posttranslational modification of AGO2, reduced the importing of AGO2 into mitochondria in diabetic cardiomyopathy. AGO2 malonylation was regulated by a cytoplasmic-localized short isoform of SIRT3 through a previously unknown demalonylase function.

CONCLUSIONS

Our findings reveal that the SIRT3-AGO2-CYTB axis links glucotoxicity to cardiac electron transport chain imbalance, providing new mechanistic insights and the basis to develop mitochondria targeting therapies for diabetic cardiomyopathy.

The pathogenic mechanism of TAR DNA-binding protein 43 (TDP-43) in amyotrophic lateral sclerosis

The onset of amyotrophic lateral sclerosis is usually characterized by focal death of both upper and/or lower motor neurons occurring in the motor cortex, basal ganglia, brainstem, and spinal cord, and commonly involves the muscles of the upper and/or lower extremities, and the muscles of the bulbar and/or respiratory regions. However, as the disease progresses, it affects the adjacent body regions, leading to generalized muscle weakness, occasionally along with memory, cognitive, behavioral, and language impairments; respiratory dysfunction occurs at the final stage of the disease. The disease has a complicated pathophysiology and currently, only riluzole, edaravone, and phenylbutyrate/taurursodiol are licensed to treat amyotrophic lateral sclerosis in many industrialized countries. The TAR DNA-binding protein 43 inclusions are observed in 97% of those diagnosed with amyotrophic lateral sclerosis. This review provides a preliminary overview of the potential effects of TAR DNA-binding protein 43 in the pathogenesis of amyotrophic lateral sclerosis, including the abnormalities in nucleoplasmic transport, RNA function, post-translational modification, liquid-liquid phase separation, stress granules, mitochondrial dysfunction, oxidative stress, axonal transport, protein quality control system, and non-cellular autonomous functions (e.g., glial cell functions and prion-like propagation).

Understanding age-related pathologic changes in TDP-43 functions and the consequence on RNA splicing and signalling in health and disease

TAR DNA binding protein-43 (TDP-43) is a key component in RNA splicing which plays a crucial role in the aging process. In neurodegenerative diseases such as amyotrophic lateral sclerosis, frontotemporal dementia and limbic-predominant age-related TDP-43 encephalopathy, TDP-43 can be mutated, mislocalised out of the nucleus of neurons and glial cells and form cytoplasmic inclusions. These TDP-43 alterations can lead to its RNA splicing dysregulation and contribute to mis-splicing of various types of RNA, such as mRNA, microRNA, and circular RNA. These changes can result in the generation of an altered transcriptome and proteome within cells, ultimately changing the diversity and quantity of gene products. In this review, we summarise the findings of novel atypical RNAs resulting from TDP-43 dysfunction and their potential as biomarkers or targets for therapeutic development.

Large-scale RNA-seq mining reveals ciclopirox triggers TDP-43 cryptic exons

Nuclear clearance and cytoplasmic aggregation of TDP-43 in neurons, initially identified in ALS-FTD, are hallmark pathological features observed across a spectrum of neurodegenerative diseases. We previously found that TDP-43 loss-of-function leads to the transcriptome-wide inclusion of deleterious cryptic exons in brains and biofluids post-mortem as well as during the presymptomatic stage of ALS-FTD, but upstream mechanisms that lead to TDP-43 dysregulation remain unclear. Here, we developed a web-based resource (SnapMine) to determine the levels of TDP-43 cryptic exon inclusion across hundreds of thousands of publicly available RNA sequencing datasets. We established cryptic exon inclusion across a variety of human cells and tissues to provide ground truth references for future studies on TDP-43 dysregulation. We then explored studies that were entirely unrelated to TDP-43 or neurodegeneration and found that ciclopirox olamine (CPX), an FDA-approved antifungal, can trigger the inclusion of TDP-43-associated cryptic exons in a variety of mouse and human primary cells. CPX induction of cryptic exon occurs via heavy metal toxicity and oxidative stress, suggesting that similar vulnerabilities could play a role in neurodegeneration. Our work demonstrates how diverse datasets can be linked through common biological features and underscores that public archives of sequencing data represent a vastly underutilized resource with tremendous potential for uncovering novel insights into complex biological mechanisms and diseases.

Homozygous ALS-linked mutations in TARDBP/TDP-43 lead to hypoactivity and synaptic abnormalities in human iPSC-derived motor neurons

Cytoplasmic mislocalization and aggregation of the RNA-binding protein TDP-43 is a pathological hallmark of the motor neuron (MN) disease amyotrophic lateral sclerosis (ALS). Furthermore, while mutations in TARDBP (encoding TDP-43) have been associated with ALS, the pathogenic consequences of these mutations remain poorly understood. Using CRISPR-Cas9, we engineered two homozygous knock-in induced pluripotent stem cell lines carrying mutations in TARDBP encoding TDP-43A382T and TDP-43G348C, two common yet understudied ALS TDP-43 variants. Motor neurons (MNs) differentiated from knock-in iPSCs had normal viability and displayed no significant changes in TDP-43 subcellular localization, phosphorylation, solubility, or aggregation compared with isogenic control MNs. However, our results highlight synaptic impairments in both TDP-43A382T and TDP-43G348C MN cultures, as reflected in synapse abnormalities and alterations in spontaneous neuronal activity. Collectively, our findings suggest that MN dysfunction may precede the occurrence of TDP-43 pathology and neurodegeneration in ALS and further implicate synaptic and excitability defects in the pathobiology of this disease.

Ferroptosis regulation through Nrf2 and implications for neurodegenerative diseases

This article provides an overview of the background knowledge of ferroptosis in the nervous system, as well as the key role of nuclear factor E2-related factor 2 (Nrf2) in regulating ferroptosis. The article takes Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) as the starting point to explore the close association between Nrf2 and ferroptosis, which is of clear and significant importance for understanding the mechanism of neurodegenerative diseases (NDs) based on oxidative stress (OS). Accumulating evidence links ferroptosis to the pathogenesis of NDs. As the disease progresses, damage to the antioxidant system, excessive OS, and altered Nrf2 expression levels, especially the inhibition of ferroptosis by lipid peroxidation inhibitors and adaptive enhancement of Nrf2 signaling, demonstrate the potential clinical significance of Nrf2 in detecting and identifying ferroptosis, as well as targeted therapy for neuronal loss and mitochondrial dysfunction. These findings provide new insights and possibilities for the treatment and prevention of NDs.

New Insights into Oxidative Stress and Inflammatory Response in Neurodegenerative Diseases

Oxidative stress (OS) and inflammation are two important and well-studied pathological hallmarks of neurodegenerative diseases (NDDs). Due to elevated oxygen consumption, the high presence of easily oxidizable polyunsaturated fatty acids and the weak antioxidant defenses, the brain is particularly vulnerable to oxidative injury. Uncertainty exists over whether these deficits contribute to the development of NDDs or are solely a consequence of neuronal degeneration. Furthermore, these two pathological hallmarks are linked, and it is known that OS can affect the inflammatory response. In this review, we will overview the last findings about these two pathways in the principal NDDs. Moreover, we will focus more in depth on amyotrophic lateral sclerosis (ALS) to understand how anti-inflammatory and antioxidants drugs have been used for the treatment of this still incurable motor neuron (MN) disease. Finally, we will analyze the principal past and actual clinical trials and the future perspectives in the study of these two pathological mechanisms.

Icariin prevents methylmercury-induced experimental neurotoxicity: Evidence from cerebrospinal fluid, blood plasma, brain samples, and in-silico investigations

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that causes significant neurodegeneration. Methylmercury (MeHg+) is a neurotoxin that induces axonal neurodegeneration and motor nerve degeneration by destroying oligodendrocytes, degenerating white matter, inducing apoptosis, excitotoxicity, and reducing myelin basic protein (MBP). This study examines the inhibition of SIRT-1 (silence information regulator 1), Nrf-2 (nuclear factor E2-related factor 2), HO-1 (heme oxygenase 1), and TDP-43 (TAR-DNA-binding protein 43) accumulation in the context of ALS, as well as the modulation of these proteins by icariin (15 and 30 mg/kg, orally), a glycoside flavonoid with neuroprotective properties. Neuroprotective icariin activates SIRT-1, Nrf-2, and HO-1, mitigating inflammation and neuronal injury in neurodegenerative disorders. In-vivo and in-silico testing of experimental ALS models confirmed icariin efficacy in modulating these cellular targets. The addition of sirtinol 10 mg/kg, an inhibitor of SIRT-1, helps determine the effectiveness of icariin. In this study, we also examined neurobehavioral, neurochemical, histopathological, and LFB (Luxol fast blue) markers in various biological samples, including Cerebrospinal fluid (CSF), blood plasma, and brain homogenates (Cerebral Cortex, Hippocampus, Striatum, mid-brain, and Cerebellum). These results demonstrate that the administration of icariin ameliorates experimental ALS and that the mechanism underlying these benefits is likely related to regulating the SIRT-1, Nrf-2, and HO-1 signaling pathways.

Vitamin B12 Deficiency and the Nervous System: Beyond Metabolic Decompensation-Comparing Biological Models and Gaining New Insights into Molecular and Cellular Mechanisms

Vitamin B12 (VitB12) is a micronutrient and acts as a cofactor for fundamental biochemical reactions: the synthesis of succinyl-CoA from methylmalonyl-CoA and biotin, and the synthesis of methionine from folic acid and homocysteine. VitB12 deficiency can determine a wide range of diseases, including nervous system impairments. Although clinical evidence shows a direct role of VitB12 in neuronal homeostasis, the molecular mechanisms are yet to be characterized in depth. Earlier investigations focused on exploring the biochemical shifts resulting from a deficiency in the function of VitB12 as a coenzyme, while more recent studies propose a broader mechanism, encompassing changes at the molecular/cellular levels. Here, we explore existing study models employed to investigate the role of VitB12 in the nervous system, including the challenges inherent in replicating deficiency/supplementation in experimental settings. Moreover, we discuss the potential biochemical alterations and ensuing mechanisms that might be modified at the molecular/cellular level (such as epigenetic modifications or changes in lysosomal activity). We also address the role of VitB12 deficiency in initiating processes that contribute to nervous system deterioration, including ROS accumulation, inflammation, and demyelination. Consequently, a complex biological landscape emerges, requiring further investigative efforts to grasp the intricacies involved and identify potential therapeutic targets.

Implications of TDP-43 in non-neuronal systems

TAR DNA-binding protein 43 (TDP-43) is a versatile RNA/DNA-binding protein with multifaceted processes. While TDP-43 has been extensively studied in the context of degenerative diseases, recent evidence has also highlighted its crucial involvement in diverse life processes beyond neurodegeneration. Here, we mainly reviewed the function of TDP-43 in non-neurodegenerative physiological and pathological processes, including spermatogenesis, embryonic development, mammary gland development, tumor formation, and viral infection, highlighting its importance as a key regulatory factor for the maintenance of normal functions throughout life. TDP-43 exhibits diverse and sometimes opposite functionality across different cell types through various mechanisms, and its roles can shift at distinct stages within the same biological system. Consequently, TDP-43 operates in both a context-dependent and a stage-specific manner in response to a variety of internal and external stimuli. Video Abstract.

Integration of FUNDC1-associated mitochondrial protein import and mitochondrial quality control contributes to TDP-43 degradation

Though TDP-43 protein can be translocated into mitochondria and causes mitochondrial damage in TDP-43 proteinopathy, little is known about how TDP-43 is imported into mitochondria. In addition, whether mitochondrial damage is caused by mitochondrial mislocalization of TDP-43 or a side effect of mitochondria-mediated TDP-43 degradation remains to be investigated. Here, our bioinformatical analyses reveal that mitophagy receptor gene FUNDC1 is co-expressed with TDP-43, and both TDP-43 and FUNDC1 expression is correlated with genes associated with mitochondrial protein import pathway in brain samples of patients diagnosed with TDP-43 proteinopathy. FUNDC1 promotes mitochondrial translocation of TDP-43 possibly by promoting TDP-43-TOM70 and DNAJA2-TOM70 interactions, which is independent of the LC3 interacting region of FUNDC1 in cellular experiments. In the transgenic fly model of TDP-43 proteinopathy, overexpressing FUNDC1 enhances TDP-43 induced mitochondrial damage, whereas down-regulating FUNDC1 reverses TDP-43 induced mitochondrial damage. FUNDC1 regulates mitochondria-mediated TDP-43 degradation not only by regulating mitochondrial TDP-43 import, but also by increasing LONP1 level and by activating mitophagy, which plays important roles in cytosolic TDP-43 clearance. Together, this study not only uncovers the mechanism of mitochondrial TDP-43 import, but also unravels the active role played by mitochondria in regulating TDP-43 homeostasis.

Characteristics of Sensory Neuron Dysfunction in Amyotrophic Lateral Sclerosis (ALS): Potential for ALS Therapy

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterised by the progressive degeneration of motor neurons, resulting in muscle weakness, paralysis, and, ultimately, death. Presently, no effective treatment for ALS has been established. Although motor neuron dysfunction is a hallmark of ALS, emerging evidence suggests that sensory neurons are also involved in the disease. In clinical research, 30% of patients with ALS had sensory symptoms and abnormal sensory nerve conduction studies in the lower extremities. Peroneal nerve biopsies show histological abnormalities in 90% of the patients. Preclinical research has reported several genetic abnormalities in the sensory neurons of animal models of ALS, as well as in motor neurons. Furthermore, the aggregation of misfolded proteins like TAR DNA-binding protein 43 has been reported in sensory neurons. This review aims to provide a comprehensive description of ALS-related sensory neuron dysfunction, focusing on its clinical changes and underlying mechanisms. Sensory neuron abnormalities in ALS are not limited to somatosensory issues; proprioceptive sensory neurons, such as MesV and DRG neurons, have been reported to form networks with motor neurons and may be involved in motor control. Despite receiving limited attention, sensory neuron abnormalities in ALS hold potential for new therapies targeting proprioceptive sensory neurons.

Janus kinase inhibitors are potential therapeutics for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a poorly treated multifactorial neurodegenerative disease associated with multiple cell types and subcellular organelles. As with other multifactorial diseases, it is likely that drugs will need to target multiple disease processes and cell types to be effective. We review here the role of Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) signalling in ALS, confirm the association of this signalling with fundamental ALS disease processes using the BenevolentAI Knowledge Graph, and demonstrate that inhibitors of this pathway could reduce the ALS pathophysiology in neurons, glia, muscle fibres, and blood cells. Specifically, we suggest that inhibition of the JAK enzymes by approved inhibitors known as Jakinibs could reduce STAT3 activation and modify the progress of this disease. Analysis of the Jakinibs highlights baricitinib as a suitable candidate due to its ability to penetrate the central nervous system and exert beneficial effects on the immune system. Therefore, we recommend that this drug be tested in appropriately designed clinical trials for ALS.

Effects of non-coding RNAs and RNA-binding proteins on mitochondrial dysfunction in diabetic cardiomyopathy

Vascular complications are the main cause of diabetes mellitus-associated morbidity and mortality. Oxidative stress and metabolic dysfunction underly injury to the vascular endothelium and myocardium, resulting in diabetic angiopathy and cardiomyopathy. Mitochondrial dysfunction has been shown to play an important role in cardiomyopathic disruptions of key cellular functions, including energy metabolism and oxidative balance. Both non-coding RNAs and RNA-binding proteins are implicated in diabetic cardiomyopathy, however, their impact on mitochondrial dysfunction in the context of this disease is largely unknown. Elucidating the effects of non-coding RNAs and RNA-binding proteins on mitochondrial pathways in diabetic cardiomyopathy would allow further insights into the pathophysiological mechanisms underlying diabetic vascular complications and could facilitate the development of new therapeutic strategies. Stem cell-based models can facilitate the study of non-coding RNAs and RNA-binding proteins and their unique characteristics make them a promising tool to improve our understanding of mitochondrial dysfunction and vascular complications in diabetes.

Nutritional and metabolic factors in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease that is classically thought to impact the motor system. Over the past 20 years, research has started to consider the contribution of non-motor symptoms and features of the disease, and how they might affect ALS prognosis. Of the non-motor features of the disease, nutritional status (for example, malnutrition) and metabolic balance (for example, weight loss and hypermetabolism) have been consistently shown to contribute to more rapid disease progression and/or earlier death. Several complex cellular changes observed in ALS, including mitochondrial dysfunction, are also starting to be shown to contribute to bioenergetic failure. The resulting energy depletion in high energy demanding neurons makes them sensitive to apoptosis. Given that nutritional and metabolic stressors at the whole-body and cellular level can impact the capacity to maintain optimal function, these factors present avenues through which we can identify novel targets for treatment in ALS. Several clinical trials are now underway evaluating the effectiveness of modifying energy balance in ALS, making this article timely in reviewing the evidence base for metabolic and nutritional interventions.

Monomerization of TDP-43 is a key determinant for inducing TDP-43 pathology in amyotrophic lateral sclerosis

The cytoplasmic aggregation of TAR DNA binding protein-43 (TDP-43), also known as TDP-43 pathology, is the pathological hallmark of amyotrophic lateral sclerosis (ALS). However, the mechanism underlying TDP-43 cytoplasmic mislocalization and subsequent aggregation remains unclear. Here, we show that TDP-43 dimerization/multimerization is impaired in the postmortem brains and spinal cords of patients with sporadic ALS and that N-terminal dimerization-deficient TDP-43 consists of pathological inclusion bodies in ALS motor neurons. Expression of N-terminal dimerization-deficient mutant TDP-43 in Neuro2a cells and induced pluripotent stem cell-derived motor neurons recapitulates TDP-43 pathology, such as Nxf1-dependent cytoplasmic mislocalization and aggregate formation, which induces seeding effects. Furthermore, TDP-DiLuc, a bimolecular luminescence complementation reporter assay, could detect decreased N-terminal dimerization of TDP-43 before TDP-43 pathological changes caused by the transcription inhibition linked to aberrant RNA metabolism in ALS. These findings identified TDP-43 monomerization as a critical determinant inducing TDP-43 pathology in ALS.

Bilirubin and Redox Stress in Age-Related Brain Diseases

Cellular redox status has a crucial role in brain physiology, as well as in pathologic conditions. Physiologic senescence, by dysregulating cellular redox homeostasis and decreasing antioxidant defenses, enhances the central nervous system's susceptibility to diseases. The reduction of free radical accumulation through lifestyle changes, and the supplementation of antioxidants as a prophylactic and therapeutic approach to increase brain health, are strongly suggested. Bilirubin is a powerful endogenous antioxidant, with more and more recognized roles as a biomarker of disease resistance, a predictor of all-cause mortality, and a molecule that may promote health in adults. The alteration of the expression and activity of the enzymes involved in bilirubin production, as well as an altered blood bilirubin level, are often reported in neurologic conditions and neurodegenerative diseases (together denoted NCDs) in aging. These changes may predict or contribute both positively and negatively to the diseases. Understanding the role of bilirubin in the onset and progression of NCDs will be functional to consider the benefits vs. the drawbacks and to hypothesize the best strategies for its manipulation for therapeutic purposes.

Mitochondrial dysfunction: roles in skeletal muscle atrophy

Mitochondria play important roles in maintaining cellular homeostasis and skeletal muscle health, and damage to mitochondria can lead to a series of pathophysiological changes. Mitochondrial dysfunction can lead to skeletal muscle atrophy, and its molecular mechanism leading to skeletal muscle atrophy is complex. Understanding the pathogenesis of mitochondrial dysfunction is useful for the prevention and treatment of skeletal muscle atrophy, and finding drugs and methods to target and modulate mitochondrial function are urgent tasks in the prevention and treatment of skeletal muscle atrophy. In this review, we first discussed the roles of normal mitochondria in skeletal muscle. Importantly, we described the effect of mitochondrial dysfunction on skeletal muscle atrophy and the molecular mechanisms involved. Furthermore, the regulatory roles of different signaling pathways (AMPK-SIRT1-PGC-1α, IGF-1-PI3K-Akt-mTOR, FoxOs, JAK-STAT3, TGF-β-Smad2/3 and NF-κB pathways, etc.) and the roles of mitochondrial factors were investigated in mitochondrial dysfunction. Next, we analyzed the manifestations of mitochondrial dysfunction in muscle atrophy caused by different diseases. Finally, we summarized the preventive and therapeutic effects of targeted regulation of mitochondrial function on skeletal muscle atrophy, including drug therapy, exercise and diet, gene therapy, stem cell therapy and physical therapy. This review is of great significance for the holistic understanding of the important role of mitochondria in skeletal muscle, which is helpful for researchers to further understanding the molecular regulatory mechanism of skeletal muscle atrophy, and has an important inspiring role for the development of therapeutic strategies for muscle atrophy targeting mitochondria in the future.

CRISPR/Cas9: implication for modeling and therapy of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a deadly neurological disease with a complicated and variable pathophysiology yet to be fully understood. There is currently no effective treatment available to either slow or terminate it. However, recent advances in ALS genomics have linked genes to phenotypes, encouraging the creation of novel therapeutic approaches and giving researchers more tools to create efficient animal models. Genetically engineered rodent models replicating ALS disease pathology have a high predictive value for translational research. This review addresses the history of the evolution of gene editing tools, the most recent ALS disease models, and the application of CRISPR/Cas9 against ALS disease.

RNA-binding proteins as a common ground for neurodegeneration and inflammation in amyotrophic lateral sclerosis and multiple sclerosis

The neurodegenerative and inflammatory illnesses of amyotrophic lateral sclerosis and multiple sclerosis were once thought to be completely distinct entities that did not share any remarkable features, but new research is beginning to reveal more information about their similarities and differences. Here, we review some of the pathophysiological features of both diseases and their experimental models: RNA-binding proteins, energy balance, protein transportation, and protein degradation at the molecular level. We make a thorough analysis on TDP-43 and hnRNP A1 dysfunction, as a possible common ground in both pathologies, establishing a potential link between neurodegeneration and pathological immunity. Furthermore, we highlight the putative variations that diverge from a common ground in an atemporal course that proposes three phases for all relevant molecular events.

Oxidative stress: roles in skeletal muscle atrophy

Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.

Early activation of cellular stress and death pathways caused by cytoplasmic TDP-43 in the rNLS8 mouse model of ALS and FTD

TAR DNA binding protein 43 (TDP-43) pathology is a key feature of over 95% of amyotrophic lateral sclerosis (ALS) and nearly half of frontotemporal dementia (FTD) cases. The pathogenic mechanisms of TDP-43 dysfunction are poorly understood, however, activation of cell stress pathways may contribute to pathogenesis. We, therefore, sought to identify which cell stress components are critical for driving disease onset and neurodegeneration in ALS and FTD. We studied the rNLS8 transgenic mouse model, which expresses human TDP-43 with a genetically-ablated nuclear localisation sequence within neurons of the brain and spinal cord resulting in cytoplasmic TDP-43 pathology and progressive motor dysfunction. Amongst numerous cell stress-related biological pathways profiled using qPCR arrays, several critical integrated stress response (ISR) effectors, including CCAAT/enhancer-binding homologous protein (Chop/Ddit3) and activating transcription factor 4 (Atf4), were upregulated in the cortex of rNLS8 mice prior to disease onset. This was accompanied by early up-regulation of anti-apoptotic gene Bcl2 and diverse pro-apoptotic genes including BH3-interacting domain death agonist (Bid). However, pro-apoptotic signalling predominated after onset of motor phenotypes. Notably, pro-apoptotic cleaved caspase-3 protein was elevated in the cortex of rNLS8 mice at later disease stages, suggesting that downstream activation of apoptosis drives neurodegeneration following failure of early protective responses. Unexpectedly, suppression of Chop in the brain and spinal cord using antisense oligonucleotide-mediated silencing had no effect on overall TDP-43 pathology or disease phenotypes in rNLS8 mice. Cytoplasmic TDP-43 accumulation therefore causes very early activation of ISR and both anti- and pro-apoptotic signalling that switches to predominant pro-apoptotic activation later in disease. These findings suggest that precise temporal modulation of cell stress and death pathways may be beneficial to protect against neurodegeneration in ALS and FTD.