MTOR-independent, autophagic enhancer trehalose prolongs motor neuron survival and ameliorates the autophagic flux defect in a mouse model of amyotrophic lateral sclerosis

CCR1 antagonist as a potential modulator of inflammatory, autophagic, and apoptotic markers in spinal cord injury

Spinal cord injury (SCI) leads to severe and lasting impairments in motor and sensory functions. The intense inflammatory response following SCI is a significant challenge, and autophagy has emerged as a key factor in the recovery process. The C-C chemokine receptor type 1 (CCR1), a G-protein coupled receptor, plays a crucial role in managing the chemokine response under stress. BX471, a selective and potent CCR1 antagonist, has been explored in various disease contexts for its therapeutic potential. In this study, we assessed the effects of BX471 in a mouse model of SCI. The treatment was administered at doses of 3 and 10 mg/kg, 1 h and 6 h after the injury occurred. Results showed that BX471 significantly improved tissue structure by positively influencing autophagy and reducing inflammation. Inflammatory markers, including CCR1 ligands RANTES, MIP-1α, TNF-α, and IL-1β, were measured using Western blot analysis. Additionally, histological evaluations revealed that BX471 effectively decreased infiltration and reduced astrocyte and microglial activation, supporting the idea that enhancing autophagy through CCR1 inhibition could promote neuronal survival. The highest efficacy was observed at the 10 mg/kg dose, leading to optimal out-comes across the assessments. These findings suggest that CCR1 blockade with BX471 may offer a promising therapeutic strategy for SCI, addressing a critical gap in the current pharmacological treatment options.

Trehalose supports the growth of Aedes aegypti cells and modifies gene expression and dengue virus replication

Trehalose is a non-reducing disaccharide that is the major sugar found in insect hemolymph fluid. Trehalose provides energy, and promotes growth, metamorphosis, stress recovery, chitin synthesis, and insect flight. Trehalase is the only enzyme responsible for the hydrolysis of trehalose, which makes it an attractive molecular target. Here we show that Aedes aegypti (Aag2) cells express trehalase and that they can grow on trehalose-containing cell culture media. Trehalase activity was confirmed by treating Aag2 cells with trehalase inhibitors, which inhibited conversion of trehalose to glucose and reduced cell proliferation. Cell entry of a fluorescent trehalose probe was dependent on trehalose concentration, suggesting that trehalose moves across the cell membrane via passive transport. Culturing Aag2 cells with trehalose-containing cell culture media led to significant changes in gene expression, intracellular lipids, and dengue virus replication and specific infectivity, and increased their susceptibility to trehalase inhibitors. These data describe an in vitro model that can be used to rapidly screen novel trehalase inhibitors and probes and underscores the importance of trehalose metabolism in Ae. aegypti physiology and transmission of a mosquito-borne virus.

Effect of oral trehalose supplementation on inflammation and wound healing in patients with peri-trochanteric fractures: study protocol for a randomised clinical trial

INTRODUCTION

Peri-trochanteric fractures, common among the elderly with osteoporosis, pose significant morbidity and mortality risks. These fractures are increasing due to the ageing population, with Nordic countries seeing a high incidence. They present challenges for orthopaedic surgeons and can lead to functional decline and high medical costs. Hip fractures have severe consequences, including pain, immobility and increased mortality. Managing wound care is complex, involving various healing phases. Trehalose, a disaccharide with antioxidant and anti-inflammatory properties, has shown promise in wound healing and other health conditions. Studies suggest its potential benefits in reducing inflammation and aiding wound healing in peri-trochanteric fracture patients, but more research is needed to confirm its clinical effectiveness in humans.

METHODS AND ANALYSIS

The study is a double-blind, placebo-controlled randomised clinical trial aiming to evaluate the effect of trehalose consumption on patients with peri-trochanteric fractures. The study will include 64 patients meeting specific inclusion criteria and will assess inflammatory markers and wound healing at different time points. Patients will be divided into two groups, one receiving trehalose and the other receiving a placebo for 12 weeks. Various measurements and assessments will be conducted, including biochemical assays, wound assessments, anthropometric measurements and dietary intake evaluations. Data analysis will be performed using SPSS software, and statistical tests will be used to compare outcomes between the intervention and control groups.

ETHICS AND DISSEMINATION

The Ethics Committee of Shahid Beheshti University of Medical Sciences (IR.SBMU.RETECH.REC.1403.191).

TRIAL REGISTRATION NUMBER

Iranian Registry of Clinical Trials. IRCT20180404039188N5. URL of trial registry record: https://irct.behdasht.gov.ir/trial/77572. Registration date: 7 July 2024.

Trehalose: Neuroprotective Effects and Mechanisms-An Updated Review

Trehalose is a naturally occurring disaccharide that has recently gained significant attention for its neuroprotective properties in various models of neurodegeneration. This review provides an overview of available experimental data on the beneficial properties of trehalose for central nervous system pathological conditions. Trehalose's impact on neuronal cell survival and function was also examined. As a result, we identified that trehalose's neuroprotection includes autophagy modulation as well as its capability to stabilize proteins and inhibit the formation of misfolded ones. Moreover, trehalose mitigates oxidative stress-induced neuronal damage by stabilizing cellular membranes and modulating mitochondrial function. Furthermore, trehalose attenuates excitotoxicity-induced neuroinflammation by suppressing pro-inflammatory cytokine release and inhibiting inflammasome activation. A possible connection of trehalose with the gut-brain axis was also examined. These findings highlight the potential therapeutic effects of trehalose in neurodegenerative diseases. According to the conclusions drawn from this study, trehalose is a promising neuroprotective agent as a result of its distinct mechanism of action, which makes this compound a candidate for further research and the development of therapeutic strategies to combat neuronal damage and promote neuroprotection in various neurological diseases.

Neuroprotective Effect of a Multistrain Probiotic Mixture in SOD1G93A Mice by Reducing SOD1 Aggregation and Targeting the Microbiota-Gut-Brain Axis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the selective loss of motor neurons. A bidirectional communication system known as the "microbiota-gut-brain" axis has a regulatory function in neurodegenerative disorders. The impact of probiotics on ALS through the "microbiota-gut-brain" axis remains uncertain. A longitudinal investigation was conducted to examine the alterations in the structure of the ileum and colon in mutant superoxide dismutase 1 (SOD1G93A) transgenic mice models of ALS by using immunofluorescence and Western blotting. Subsequently, the mice were administered a multistrain probiotic mixture (LBE) or vehicle orally, starting from 60 days of age until the terminal stage of the disease. The effects of these agents on the behavior, gut microbiota, microbial metabolites, and pathological processes of the spinal and intestine of SOD1G93A mice were analyzed, with a focus on exploring potential protective mechanisms. SOD1G93A mice exhibit various structural abnormalities in the intestine. Oral administration of LBE improved the proinflammatory response, reduced aberrant superoxide dismutase 1 (SOD1) aggregation, and protected neuronal cells in the intestine and spinal cord of SOD1G93A mice. Furthermore, LBE treatment resulted in a change in intestinal microbiota, an increase in short-chain fatty acid levels, and an enhancement in autophagy flux. SOD1G93A mice exhibited various structural abnormalities in the intestine. LBE can improve the proinflammatory response, reduce aberrant SOD1 aggregation, and protect neuronal cells in the spinal cord and intestine of SOD1G93A mice. The positive effect of LBE can be attributed to increased short-chain fatty acids and enhanced autophagy flux.

Unraveling autophagic imbalances and therapeutic insights in Mecp2-deficient models

Loss-of-function mutations in MECP2 are associated to Rett syndrome (RTT), a severe neurodevelopmental disease. Mainly working as a transcriptional regulator, MeCP2 absence leads to gene expression perturbations resulting in deficits of synaptic function and neuronal activity. In addition, RTT patients and mouse models suffer from a complex metabolic syndrome, suggesting that related cellular pathways might contribute to neuropathogenesis. Along this line, autophagy is critical in sustaining developing neuron homeostasis by breaking down dysfunctional proteins, lipids, and organelles.Here, we investigated the autophagic pathway in RTT and found reduced content of autophagic vacuoles in Mecp2 knock-out neurons. This correlates with defective lipidation of LC3B, probably caused by a deficiency of the autophagic membrane lipid phosphatidylethanolamine. The administration of the autophagy inducer trehalose recovers LC3B lipidation, autophagosomes content in knock-out neurons, and ameliorates their morphology, neuronal activity and synaptic ultrastructure. Moreover, we provide evidence for attenuation of motor and exploratory impairment in Mecp2 knock-out mice upon trehalose administration. Overall, our findings open new perspectives for neurodevelopmental disorders therapies based on the concept of autophagy modulation.

Acquisition of neurodegenerative features in isogenic OPTN(E50K) human stem cell-derived retinal ganglion cells associated with autophagy disruption and mTORC1 signaling reduction

The ability to derive retinal ganglion cells (RGCs) from human pluripotent stem cells (hPSCs) has led to numerous advances in the field of retinal research, with great potential for the use of hPSC-derived RGCs for studies of human retinal development, in vitro disease modeling, drug discovery, as well as their potential use for cell replacement therapeutics. Of all these possibilities, the use of hPSC-derived RGCs as a human-relevant platform for in vitro disease modeling has received the greatest attention, due to the translational relevance as well as the immediacy with which results may be obtained compared to more complex applications like cell replacement. While several studies to date have focused upon the use of hPSC-derived RGCs with genetic variants associated with glaucoma or other optic neuropathies, many of these have largely described cellular phenotypes with only limited advancement into exploring dysfunctional cellular pathways as a consequence of the disease-associated gene variants. Thus, to further advance this field of research, in the current study we leveraged an isogenic hPSC model with a glaucoma-associated mutation in the Optineurin (OPTN) protein, which plays a prominent role in autophagy. We identified an impairment of autophagic-lysosomal degradation and decreased mTORC1 signaling via activation of the stress sensor AMPK, along with subsequent neurodegeneration in OPTN(E50K) RGCs differentiated from hPSCs, and have further validated some of these findings in a mouse model of ocular hypertension. Pharmacological inhibition of mTORC1 in hPSC-derived RGCs recapitulated disease-related neurodegenerative phenotypes in otherwise healthy RGCs, while the mTOR-independent induction of autophagy reduced protein accumulation and restored neurite outgrowth in diseased OPTN(E50K) RGCs. Taken together, these results highlighted that autophagy disruption resulted in increased autophagic demand which was associated with downregulated signaling through mTORC1, contributing to the degeneration of RGCs.

Unlocking Trehalose's versatility: A comprehensive Journey from biosynthesis to therapeutic applications

For over forty years, a sugar of rare configuration known as trehalose (two molecules of glucose linked at their 1-carbons), has been recognised for more than just its roles as a storage compound. The ability of trehalose to protect an extensive range of biological materials, for instance cell lines, tissues, proteins and DNA, has sparked considerable interest in the biotechnology and pharmaceutical industries. Currently, trehalose is now being investigated as a promising therapeutic candidate for human use, as it has shown potential to reduce disease severity in various experimental models. Despite its diverse biological effects, the precise mechanism underlying this observation remain unclear. Therefore, this review delves into the significance of trehalose biosynthesis pathway in the development of novel drug, investigates the inhibitors of trehalose synthesis and evaluates the binding efficiency of T6P with TPS1. Additionally, it also emphasizes the knowledge about the protective effect of trehalose on modulation of autophagy, combating viral infections, addressing the conditions like cancer and neurodegenerative diseases based on the recent advancement. Furthermore, review also highlight the trehalose's emerging role as a surfactant in delivering monoclonal antibodies that will further broadening its potential application in biomedicines.

Gut microbiota immune cross-talk in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the loss of motor neurons. While there has been significant progress in defining the genetic contributions to ALS, greater than 90 ​% of cases are sporadic, which suggests an environmental component. The gut microbiota is altered in ALS and is an ecological factor that contributes to disease by modulating immunologic, metabolic, and neuronal signaling. Depleting the microbiome worsens disease in the SOD1 ALS animal model, while it ameliorates disease in the C9orf72 model of ALS, indicating critical subtype-specific interactions. Furthermore, administering beneficial microbiota or microbial metabolites can slow disease progression in animal models. This review discusses the current state of microbiome research in ALS, including interactions with different ALS subtypes, evidence in animal models and human studies, key immunologic and metabolomic mediators, and a path toward microbiome-based therapies for ALS.

Low-intensity pulsed ultrasound modulates disease progression in the SOD1G93A mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the progressive loss of motor neurons in the brain and spinal cord, and there are no effective drug treatments. Low-intensity pulsed ultrasound (LIPUS) has garnered attention as a promising noninvasive neuromodulation method. In this study, we investigate its effects on the motor cortex and underlying mechanisms using the SOD1G93A mouse model of ALS. Our results show that LIPUS treatment delays disease onset and prolongs lifespan in ALS mice. LIPUS significantly increases cerebral blood flow in the motor cortex by preserving vascular endothelial cell integrity and increasing microvascular density, which may be mediated via the ion channel TRPV4. RNA sequencing analysis reveals that LIPUS substantially reduces the expression of genes associated with neuroinflammation. These findings suggest that LIPUS applied to the motor cortex may represent a potentially effective therapeutic tool for the treatment of ALS.

Herbal medicines for SOD1G93A mice of amyotrophic lateral sclerosis: preclinical evidence and possible immunologic mechanism

Currently, there is no cure or effective treatment for Amyotrophic Lateral Sclerosis (ALS). The mechanisms underlying ALS remain unclear, with immunological factors potentially playing a significant role. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), a systematic review of preclinical studies was conducted, searching seven databases including PubMed, covering literature from the inception of the databases to April 10, 2024. Methodological quality of the included literature was assessed using CAMARADES, while the risk of bias in the included studies was evaluated using SYRCLE's ROB tool. Review Manager 5.4.1 statistical software was used for meta-analysis of the outcomes. The scoping review followed the Joanna Briggs Institute Methodological Guidelines and reporting of this review followed the PRISMA-extension for Scoping Reviews (PRISMA -ScR) checklist to explore the immunological mechanisms of Herbal Medicine (HM) in treating ALS. This systematic review and meta-analysis involved 18 studies with a total of 443 animals. The studies scored between 4 to 8 for methodological quality and 3 to 7 for risk of bias, both summing up to 10.A remarkable effects of HM in ALS mice, including onset time(Standardized Mean Difference(SMD): 1.75, 95% Confidence Interval(CI) (1.14 ~ 2.36), Z = 5.60, P < 0.01), survival time(SMD = 1.42, 95% CI (0.79 ~ 2.04), Z = 4.44, P < 0.01), stride length(SMD=1.90, 95% CI (1.21 to 2.59), Z = 5.39, P < 0.01) and duration time (Mean Difference(MD)=6.79, 95% CI [-0.28, 13.87], Z=1.88, P =0.06), showing HM's certain efficiency in treating ALS mice. The scoping review ultimately included 35 articles for review. HMs may treat ALS through mechanisms such as combating oxidative stress, excitatory amino acid toxicity, and calcium cytotoxicity, understanding and exploring the mechanisms will bring hope to patients. Individual herbs and their formulations within HM address ALS through a variety of immune pathways, including safeguarding the blood-brain barrier, countering neuroinflammation, impeding complement system activation, mitigating natural killer cell toxicity, and regulating T cell-mediated immune pathways. The preclinical evidence supports the utilization of HM as a conventional treatment for ALS mice. Growing evidence indicates that HM may potentially delay neurological degeneration in ALS by activating diverse signaling pathways, especially immune pathways.

Advances in the study of mitophagy in osteoarthritis

Osteoarthritis (OA), characterized by cartilage degeneration, synovial inflammation, and subchondral bone remodeling, is among the most common musculoskeletal disorders globally in people over 60 years of age. The initiation and progression of OA involves the abnormal metabolism of chondrocytes as an important pathogenic process. Cartilage degeneration features mitochondrial dysfunction as one of the important causative factors of abnormal chondrocyte metabolism. Therefore, maintaining mitochondrial homeostasis is an important strategy to mitigate OA. Mitophagy is a vital process for autophagosomes to target, engulf, and remove damaged and dysfunctional mitochondria, thereby maintaining mitochondrial homeostasis. Cumulative studies have revealed a strong association between mitophagy and OA, suggesting that the regulation of mitophagy may be a novel therapeutic direction for OA. By reviewing the literature on mitophagy and OA published in recent years, this paper elaborates the potential mechanism of mitophagy regulating OA, thus providing a theoretical basis for studies related to mitophagy to develop new treatment options for OA.

Mitochondrial homeostasis regulation: A promising therapeutic target for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) and the presence of Lewy bodies (LBs) or Lewy neurites (LNs) which consist of α-synuclein (α-syn) and a complex mix of other biomolecules. Mitochondrial dysfunction is widely believed to play an essential role in the pathogenesis of PD and other related neurodegenerative diseases. But mitochondrial dysfunction is subject to complex genetic regulation. There is increasing evidence that PD-related genes directly or indirectly affect mitochondrial integrity. Therefore, targeted regulation of mitochondrial function has great clinical application prospects in the treatment of PD. However, lots of PD drugs targeting mitochondria have been developed but their clinical therapeutic effects are not ideal. This review aims to reveal the role of mitochondrial dysfunction in the pathogenesis of neurodegenerative diseases based on the mitochondrial structure and function, which may highlight potential interventions and therapeutic targets for the development of PD drugs to recover mitochondrial dysfunction in neurodegenerative diseases.

Role of Autophagy and Mitophagy in Neurodegenerative Disorders

Autophagy is a self-destructive cellular process that removes essential metabolites and waste from inside the cell to maintain cellular health. Mitophagy is the process by which autophagy causes disruption inside mitochondria and the total removal of damaged or stressed mitochondria, hence enhancing cellular health. The mitochondria are the powerhouses of the cell, performing essential functions such as ATP (adenosine triphosphate) generation, metabolism, Ca2+ buffering, and signal transduction. Many different mechanisms, including endosomal and autophagosomal transport, bring these substrates to lysosomes for processing. Autophagy and endocytic processes each have distinct compartments, and they interact dynamically with one another to complete digestion. Since mitophagy is essential for maintaining cellular health and using genetics, cell biology, and proteomics techniques, it is necessary to understand its beginning, particularly in ubiquitin and receptor-dependent signalling in injured mitochondria. Despite their similar symptoms and emerging genetic foundations, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) have all been linked to abnormalities in autophagy and endolysosomal pathways associated with neuronal dysfunction. Mitophagy is responsible for normal mitochondrial turnover and, under certain physiological or pathological situations, may drive the elimination of faulty mitochondria. Due to their high energy requirements and post-mitotic origin, neurons are especially susceptible to autophagic and mitochondrial malfunction. This article focused on the importance of autophagy and mitophagy in neurodegenerative illnesses and how they might be used to create novel therapeutic approaches for treating a wide range of neurological disorders.

Trehalose improves the movement ability of AβarcDrosophila by restoring the damaged mitochondria

Background

The deposition of Aβ42 has been regarded as one of the important pathological features of Alzheimer's disease (AD). However, drug development for Aβ42 toxicity has been progressed slowly.

Objective

Our aim was to introduce the effect and related mechanism of trehalose on an Aβarc (arctic mutant Aβ42) Drosophila AD model.

Methods

The human Aβarc was expressed in Drosophila to construct the AD model. Trehalose was added to the culture vial. The movement ability was determined by detecting climbing ability and flight ability. Enzyme-linked immunosorbent assay was used to detect the levels of Aβarc, ATP, and lactate. Electron microscopy assay, mitochondrial membrane potential assay, and mitochondrial respiration assay were used to assess the mitochondrial structure and function.

Results

Trehalose strongly improved the movement ability of Aβarc Drosophila in a concentration gradient-dependent manner. Furthermore, trehalose increased the content of ATP and decreased the content of Aβarc and lactate both in the brain and thorax of Aβarc Drosophila. More importantly, the mitochondrial structure and function were greatly improved by trehalose treatment in Aβarc Drosophila.

Conclusion

Trehalose improves movement ability at least partly by reducing the Aβarc level and restoring the mitochondrial structure and function in Aβarc Drosophila.

Fundamental roles of the Optineurin gene in the molecular pathology of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive loss of motor neurons (MNs) in the brain and spinal cord. It is caused by multiple factors, including mutations in any one of several specific genes. Optineurin (OPTN) mutation is an essential cause of some familial and sporadic ALS. Besides, as a multifunctional protein, OPTN is highly expressed and conserved in the central nervous system. OPTN exerts its functions by interacting with various proteins, often acting as an adaptor to provide a link between two or more core proteins related to autophagy and inflammation, etc. OPTN mutation mainly results in its function deficiency, which alters these interactions, leading to functional impairment in many processes. Meanwhile, OPTN immunopositive inclusions are also confirmed in the cases of ALS due to C9ORF72, FUS, TARDBP, and SOD1 mutations. Therefore, OPTN gene may play fundamental roles in the molecular pathology of ALS in addition to OPTN mutation. In this review, we summarize the recent advances in the ALS pathology of OPTN defect, such as mitophagy disorder, neuroinflammation, neuronal axonal degeneration, vesicular transport dysfunction, etc., which will provide a reference for research on the pathogenesis and treatment of ALS.

Discovery of a Small-Molecule Modulator of the Autophagy-Lysosome Pathway That Targets Lamin A/C and LAMP1, Induces Autophagic Flux, and Affects Lysosome Positioning in Neurons

Autophagy is a major catabolic degradation and recycling process that maintains homeostasis in cells and is especially important in postmitotic neurons. We implemented a high-content phenotypic assay to discover small molecules that promote autophagic flux and completed target identification and validation studies to identify protein targets that modulate the autophagy pathway and promote neuronal health and survival. Efficient syntheses of the prioritized compounds were developed to readily access analogues of the initial hits, enabling initial structure-activity relationship studies to improve potency and preparation of a biotin-tagged pulldown probe that retains activity. This probe facilitated target identification and validation studies through pulldown and competition experiments using both an unbiased proteomics approach and western blotting to reveal Lamin A/C and LAMP1 as the protein targets of compound RH1115. Evaluation of RH1115 in neurons revealed that this compound induces changes to LAMP1 vesicle properties and alters lysosome positioning. Dysfunction of the autophagy-lysosome pathway has been implicated in a variety of neurodegenerative diseases, including Alzheimer's disease, highlighting the value of new strategies for therapeutic modulation and the importance of small-molecule probes to facilitate the study of autophagy regulation in cultured neurons and in vivo.

Trehalose-Bearing Carriers to Target Impaired Autophagy and Protein Aggregation Diseases

In recent years, trehalose, a natural disaccharide, has attracted growing attention because of the discovery of its potential to induce autophagy. Trehalose has also been demonstrated to preserve the protein's structural integrity and to limit the aggregation of pathologically misfolded proteins. Both of these properties have made trehalose a promising therapeutic candidate to target autophagy-related disorders and protein aggregation diseases. Unfortunately, trehalose has poor bioavailability due to its hydrophilic nature and susceptibility to enzymatic degradation. Recently, trehalose-bearing carriers, in which trehalose is incorporated either by chemical conjugation or physical entrapment, have emerged as an alternative option to free trehalose to improve its efficacy, particularly for the treatment of neurodegenerative diseases, atherosclerosis, nonalcoholic fatty liver disease (NAFLD), and cancers. In the current Perspective, we discuss all existing literature in this emerging field and try to identify key challenges for researchers intending to develop trehalose-bearing carriers to stimulate autophagy or inhibit protein aggregation.

Excess PrPC inhibits muscle cell differentiation via miRNA-enhanced liquid-liquid phase separation implicated in myopathy

The cellular prion protein (PrPC) is required for skeletal muscle function. Here, we report that a higher level of PrPC accumulates in the cytoplasm of the skeletal muscle of six myopathy patients compared to controls. PrPC inhibits skeletal muscle cell autophagy, and blocks myoblast differentiation. PrPC selectively binds to a subset of miRNAs during myoblast differentiation, and the colocalization of PrPC and miR-214-3p was observed in the skeletal muscle of six myopathy patients with excessive PrPC. We demonstrate that PrPC is overexpressed in skeletal muscle cells under pathological conditions, inhibits muscle cell differentiation by physically interacting with a subset of miRNAs, and selectively recruits these miRNAs into its phase-separated condensate in living myoblasts, which in turn enhances liquid-liquid phase separation of PrPC, promotes pathological aggregation of PrP, and results in the inhibition of autophagy-related protein 5-dependent autophagy and muscle bundle formation in myopathy patients characterized by incomplete muscle regeneration.

A neuroprotective dose of trehalose is harmless to metabolic organs: comprehensive histopathological analysis of liver, pancreas, and kidney

BACKGROUND

Trehalose is a non-reducing disaccharide synthesized by lower organisms. It has recently received special attention because of its neuroprotective properties by stimulating autophagy in Parkinson's disease (PD) models. Therefore, evaluating whether trehalose affects metabolic organs is vital to determine its neurotherapeutic safety.

METHODS

We validated the trehalose neuroprotective dosage in a PD model induced with intraperitoneal paraquat administration twice weekly for 7 weeks. One week before paraquat administration, mice were treated with trehalose in the drinking water and continued along with paraquat treatment. Histological and morphometrical analyses were conducted on the organs involved in trehalose metabolism, including the liver, pancreas, and kidney.

RESULTS

Paraquat-induced dopaminergic neuronal loss was significantly decreased by trehalose. After trehalose treatment, the liver morphology, the mononucleated/binucleated hepatocytes percentage, and sinusoidal diameter remained unchanged in each liver lobes. Endocrine and exocrine pancreas's histology was not affected, nor was any fibrotic process observed. The islet of Langerhans's structure was preserved when analyzing the area, the largest and smallest diameter, and circularity. Renal morphology remained undamaged, and no changes were identified within the glomerular basement membrane. The renal corpuscle structure did not suffer alterations in the Bowman's space, area, diameter, circularity, perimeter, and cellularity. Besides, the renal tubular structures's luminal area and internal and external diameter were preserved.

CONCLUSION

Our study demonstrates that systemic trehalose administration preserved the typical histological architecture of the organs involved in its metabolism, supporting its safety as a potential neuroprotective agent.

Lysosomes in senescence and aging

Dysfunction of lysosomes, the primary hydrolytic organelles in animal cells, is frequently associated with aging and age-related diseases. At the cellular level, lysosomal dysfunction is strongly linked to cellular senescence or the induction of cell death pathways. However, the precise mechanisms by which lysosomal dysfunction participates in these various cellular or organismal phenotypes have remained elusive. The ability of lysosomes to degrade diverse macromolecules including damaged proteins and organelles puts lysosomes at the center of multiple cellular stress responses. Lysosomal activity is tightly regulated by many coordinated cellular processes including pathways that function inside and outside of the organelle. Here, we collectively classify these coordinated pathways as the lysosomal processing and adaptation system (LYPAS). We review evidence that the LYPAS is upregulated by diverse cellular stresses, its adaptability regulates senescence and cell death decisions, and it can form the basis for therapeutic manipulation for a wide range of age-related diseases and potentially for aging itself.

Leflunomide alleviates obesity via activation of the TAK1-AMPK pathway and induction of lipophagy

Lipophagy is a subset of selective autophagy that specifically degrades lipid droplets and plays an important role in obesity. Leflunomide treatment in rheumatoid arthritis (RA) patients has been associated with weight loss and decreased blood glucose levels, which cannot be attributed to its known side effects. Our prior studies showed that A77 1726, the active metabolite of leflunomide, acts as an inhibitor of S6K1 to sensitize the insulin receptor and control hyperglycemia. Whether the anti-obesity effect of leflunomide is mediated by targeting S6K1 and its underlying mechanisms remain unclear. Here, we report that A77 1726 induced LC3 lipidation and increased the formation of autophagosomes and lipoautolysosomes in 3T3-L1 adipocytes by activating TGF-β-activated kinase 1 (TAK1), AMP-activated kinase (AMPK), and Unc-51 like autophagy-activated kinase 1 (ULK1). A77 1726 reduced the content of lipid droplets in 3T3-L1 adipocytes, which was blocked by bafilomycin or by beclin-1 knockdown. Similar observations were made in murine adipocytes differentiated from S6K1-/- embryonic fibroblasts (MEFs). Leflunomide treatment restricted bodyweight gains in ob/ob mice and reduced the visceral fat deposit and the size of adipocytes. Leflunomide treatment induced autophagy in adipose and liver tissues and reduced hepatic lipid contents. Consistently, S6K1 knockout increased the levels of LC3 lipidation in the liver, muscle, and fat of S6K-/- mice. Leflunomide treatment and S6K1 deficiency both induced TAK1, AMPK, and ULK1 phosphorylation in these tissues. These observations collectively suggest that leflunomide controls obesity in part by activating AMPK and inducing lipophagy. Our study provides insights into the mechanisms of leflunomide-mediated anti-obesity activity.

Lipoic acid inhibits cognitive impairment induced by multiple cell phones in young male rats: role of Sirt1 and Atg7 pathway

The utilization of digital technology has grown rapidly in the past three decades. With this rapid increase, cell phones emit electromagnetic radiation; that is why electromagnetic field (EMF) has become a substantial new pollution source in modern civilization, mainly having adverse effects on the brain. While such a topic attracted many researchers' scopes, there are still minimal discoveries made regarding chronic exposure to EMF. The extensive use of cell phones may affect children's cognition even indirectly if parents and guardians used their phones repeatedly near them. This study aims to investigate possible lipoic acid (LA) effects on cognitive functions and hippocampal structure in young male rats exposed to electromagnetic fields (EMF) emitted from multiple cell phones. Forty young male Wistar rats were randomly allocated into three groups: control, multiple cell phones-exposed and lipoic acid-treated rats. By the end of the experimental period, the Morris water maze was used as a cognitive test. The rats were sacrificed for the collection of serum and hippocampal tissue. These serum samples were then utilized for assessment of Liver function tests. The level ofglutamate, acetylcholine (Ach) and malondialdehyde (MDA) was estimated, in addition to evaluating the expression of autophagy-related protein-7 (Atg7) and Sirt1 genes. The left hippocampal specimens were used for histopathological studies. Results showed that multiple cell phone-exposed rats exhibited shorter latency time to reach the platform by the fifth day of training; additionally, there was a reduction in consolidation of spatial long-term memory. Correspondingly, there was an elevation of hippocampal Ach, glutamate, and MDA levels; accompanied by up-regulation of hippocampal Sirt1 and Atg7 gene expression. Compared to the EMF-exposed group, LA administration improved both learning and memory, this was proved by the significant decline in hippocampal MDA and Ach levels, the higher hippocampal glutamate, the downregulated hippocampal Sirt1 gene expression and the upregulated Atg7 gene expression. In conclusion, EMF exposure could enhance learning ability; however, it interfered with long-term memory consolidation shown by higher hippocampal Ach levels. Lipoic acid treatment improved both learning and memory by enhancing autophagy and hippocampal glutamate level and by the reduced Ach levels and Sirt1 gene expression.

Autophagy-related proteins: Potential diagnostic and prognostic biomarkers of aging-related diseases

Autophagy plays a key role in cellular, tissue and organismal homeostasis and in the production of the energy load needed at critical times during development and in response to nutrient shortage. Autophagy is generally considered as a pro-survival mechanism, although its deregulation has been linked to non-apoptotic cell death. Autophagy efficiency declines with age, thus contributing to many different pathophysiological conditions, such as cancer, cardiomyopathy, diabetes, liver disease, autoimmune diseases, infections, and neurodegeneration. Accordingly, it has been proposed that the maintenance of a proper autophagic activity contributes to the extension of the lifespan in different organisms. A better understanding of the interplay between autophagy and risk of age-related pathologies is important to propose nutritional and life-style habits favouring disease prevention as well as possible clinical applications aimed at promoting long-term health.

Profiling neuroprotective potential of trehalose in animal models of neurodegenerative diseases: a systematic review

Trehalose, a unique nonreducing crystalline disaccharide, is a potential disease-modifying treatment for neurodegenerative diseases associated with protein misfolding and aggregation due to aging, intrinsic mutations, or autophagy dysregulation. This systematic review summarizes the effects of trehalose on its underlying mechanisms in animal models of selected neurodegenerative disorders (tau pathology, synucleinopathy, polyglutamine tract, and motor neuron diseases). All animal studies on neurodegenerative diseases treated with trehalose published in Medline (accessed via EBSCOhost) and Scopus were considered. Of the 2259 studies screened, 29 met the eligibility criteria. According to the SYstematic Review Center for Laboratory Animal Experiment (SYRCLE) risk of bias tool, we reported 22 out of 29 studies with a high risk of bias. The present findings support the purported role of trehalose in autophagic flux and protein refolding. This review identified several other lesser-known pathways, including modifying amyloid precursor protein processing, inhibition of reactive gliosis, the integrity of the blood-brain barrier, activation of growth factors, upregulation of the downstream antioxidant signaling pathway, and protection against mitochondrial defects. The absence of adverse events and improvements in the outcome parameters were observed in some studies, which supports the transition to human clinical trials. It is possible to conclude that trehalose exerts its neuroprotective effects through both direct and indirect pathways. However, heterogeneous methodologies and outcome measures across the studies rendered it impossible to derive a definitive conclusion. Translational studies on trehalose would need to clarify three important questions: 1) bioavailability with oral administration, 2) optimal time window to confer neuroprotective benefits, and 3) optimal dosage to confer neuroprotection.

In Silico Exploration of Metabolically Active Peptides as Potential Therapeutic Agents against Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is regarded as a fatal neurodegenerative disease that is featured by progressive damage of the upper and lower motor neurons. To date, over 45 genes have been found to be connected with ALS pathology. The aim of this work was to computationally identify unique sets of protein hydrolysate peptides that could serve as therapeutic agents against ALS. Computational methods which include target prediction, protein-protein interaction, and peptide-protein molecular docking were used. The results showed that the network of critical ALS-associated genes consists of ATG16L2, SCFD1, VAC15, VEGFA, KEAP1, KIF5A, FIG4, TUBA4A, SIGMAR1, SETX, ANXA11, HNRNPL, NEK1, C9orf72, VCP, RPSA, ATP5B, and SOD1 together with predicted kinases such as AKT1, CDK4, DNAPK, MAPK14, and ERK2 in addition to transcription factors such as MYC, RELA, ZMIZ1, EGR1, TRIM28, and FOXA2. The identified molecular targets of the peptides that support multi-metabolic components in ALS pathogenesis include cyclooxygenase-2, angiotensin I-converting enzyme, dipeptidyl peptidase IV, X-linked inhibitor of apoptosis protein 3, and endothelin receptor ET-A. Overall, the results showed that AGL, APL, AVK, IIW, PVI, and VAY peptides are promising candidates for further study. Future work would be needed to validate the therapeutic properties of these hydrolysate peptides by in vitro and in vivo approaches.

Bicalutamide and Trehalose Ameliorate Spinal and Bulbar Muscular Atrophy Pathology in Mice

Spinal and bulbar muscular atrophy (SBMA) is characterized by motor neuron (MN) degeneration that leads to slowly progressive muscle weakness. It is considered a neuromuscular disease since muscle has a primary role in disease onset and progression. SBMA is caused by a CAG triplet repeat expansion in the androgen receptor (AR) gene. The translated poly-glutamine (polyQ) tract confers a toxic gain of function to the mutant AR altering its folding, causing its aggregation into intracellular inclusions, and impairing the autophagic flux. In an in vitro SBMA neuronal model, we previously showed that the antiandrogen bicalutamide and trehalose, a natural disaccharide stimulating autophagy, block ARpolyQ activation, reduce its nuclear translocation and toxicity and facilitate the autophagic degradation of cytoplasmic AR aggregates. Here, in a knock-in SBMA mouse model (KI AR113Q), we show that bicalutamide and trehalose ameliorated SBMA pathology. Bicalutamide reversed the formation of the AR insoluble forms in KI AR113Q muscle, preventing autophagic flux blockage. We demonstrated that apoptosis is activated in KI AR113Q muscle, and that both compounds prevented its activation. We detected a decrease of mtDNA and an increase of OXPHOS enzymes, already at early symptomatic stages; these alterations were reverted by trehalose. Overall, bicalutamide and/or trehalose led to a partial recovery of muscle morphology and function, and improved SBMA mouse motor behavior, inducing an extension of their survival. Thus, bicalutamide and trehalose, by counteracting ARpolyQ toxicity in skeletal muscle, are valuable candidates for future clinical trials in SBMA patients.

PM2.5 exposure triggers cell death through lysosomal membrane permeabilization and leads to ferroptosis insensitivity via the autophagy dysfunction/p62-KEAP1-NRF2 activation in neuronal cells

PM2.5 exposure can be associated with the onset of neurodegenerative diseases, with oxidative stress-induced cellular homeostasis disruption and cell death as one of the main mechanisms. However, the exact cellular and molecular processes are still rarely investigated. Autophagy and KEAP1-NRF2 (Kelch-like ECH-Associating protein 1-nuclear factor erythroid 2 related factor 2) signaling pathway are two main cellular defense systems for maintaining cellular homeostasis and resisting oxidative stress. In this study, we primarily investigated the role of autophagy and KEAP1-NRF2 in regulating cell death resulting from PM2.5 exposure in mouse neuroblastoma N2a cells. Our results showed that PM2.5 exposure disrupted autophagic flux by impairing lysosomal function, including lysosomal alkalinization, increased lysosome membrane permeabilization (LMP), and Cathepsin B release. Furthermore, dysregulated autophagy enhances NRF2 activity in a p62-dependent manner, which then initiates the expression of a series of antioxidant genes and increases cellular insensitivity to ferroptosis. Meanwhile, autophagy dysfunction impairs the intracellular degradation of ferroptosis related proteins such as GPX4 and ferritin. As these proteins accumulate, cells also become less sensitive to ferroptosis. LMP-associated cell death may be the main mechanism of PM2.5-induced N2a cytotoxicity. Our results may provide insights into the mechanisms of PM2.5-induced neurotoxicity and predict effective prevention and treatment strategies.

Increased expression of coronin-1a in amyotrophic lateral sclerosis: a potential diagnostic biomarker and therapeutic target

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease. At present, no definite ALS biomarkers are available. In this study, exosomes from the plasma of patients with ALS and healthy controls were extracted, and differentially expressed exosomal proteins were compared. Among them, the expression of exosomal coronin-1a (CORO1A) was 5.3-fold higher than that in the controls. CORO1A increased with disease progression at a certain proportion in the plasma of patients with ALS and in the spinal cord of ALS mice. CORO1A was also overexpressed in NSC-34 motor neuron-like cells, and apoptosis, oxidative stress, and autophagic protein expression were evaluated. CORO1A overexpression resulted in increased apoptosis and oxidative stress, overactivated autophagy, and hindered the formation of autolysosomes. Moreover, CORO1A activated Ca2+-dependent phosphatase calcineurin, thereby blocking the fusion of autophagosomes and lysosomes. The inhibition of calcineurin activation by cyclosporin A reversed the damaged autolysosomes. In conclusion, the role of CORO1A in ALS pathogenesis was discovered, potentially affecting the disease onset and progression by blocking autophagic flux. Therefore, CORO1A might be a potential biomarker and therapeutic target for ALS.

Loss of endosomal exchanger NHE6 leads to pathological changes in tau in human neurons

Disruption of endolysosomal and autophagy-lysosomal systems is increasingly implicated in neurodegeneration. Sodium-proton exchanger 6 (NHE6) contributes to the maintenance of proper endosomal pH, and loss-of function mutations in the X-linked NHE6 lead to Christianson syndrome (CS) in males. Neurodegenerative features of CS are increasingly recognized, with postmortem and clinical data implicating a role for tau. We generated cortical neurons from NHE6 knockout (KO) and isogenic wild-type control human induced pluripotent stem cells. We report elevated phosphorylated and sarkosyl-insoluble tau in NHE6 KO neurons. We demonstrate that NHE6 KO leads to lysosomal and autophagy dysfunction involving reduced lysosomal number and protease activity, diminished autophagic flux, and p62 accumulation. Finally, we show that treatment with trehalose or rapamycin, two enhancers of autophagy-lysosomal function, each partially rescue this tau phenotype. We provide insight into the neurodegenerative processes underlying NHE6 loss of function and into the broader role of the endosome-lysosome-autophagy network in neurodegeneration.

New Insights into the Molecular Interplay between Human Herpesviruses and Alzheimer’s Disease—A Narrative Review

Human herpesviruses (HHVs) have been implicated as possible risk factors in Alzheimer’s disease (AD) pathogenesis. Persistent lifelong HHVs infections may directly or indirectly contribute to the generation of AD hallmarks: amyloid beta (Aβ) plaques, neurofibrillary tangles composed of hyperphosphorylated tau proteins, and synaptic loss. The present review focuses on summarizing current knowledge on the molecular mechanistic links between HHVs and AD that include processes involved in Aβ accumulation, tau protein hyperphosphorylation, autophagy, oxidative stress, and neuroinflammation. A PubMed search was performed to collect all the available research data regarding the above mentioned mechanistic links between HHVs and AD pathology. The vast majority of research articles referred to the different pathways exploited by Herpes Simplex Virus 1 that could lead to AD pathology, while a few studies highlighted the emerging role of HHV 6, cytomegalovirus, and Epstein–Barr Virus. The elucidation of such potential links may guide the development of novel diagnostics and therapeutics to counter this devastating neurological disorder that until now remains incurable.

Disaccharide Trehalose in Experimental Therapies for Neurodegenerative Disorders: Molecular Targets and Translational Potential

Induction of autophagy is a prospective approach to the treatment of neurodegeneration. In the recent decade, trehalose attracted special attention. It is an autophagy inducer with negligible adverse effects and is approved for use in humans according to FDA requirements. Trehalose has a therapeutic effect in various experimental models of diseases. This glucose disaccharide with a flexible α-1-1'-glycosidic bond has unique properties: induction of mTOR-independent autophagy (with kinase AMPK as the main target) and a chaperone-like effect on proteins imparting them natural spatial structure. Thus, it can reduce the accumulation of neurotoxic aberrant/misfolded proteins. Trehalose has an anti-inflammatory effect and inhibits detrimental oxidative stress partially owing to the enhancement of endogenous antioxidant defense represented by the Nrf2 protein. The disaccharide activates lysosome and autophagosome biogenesis pathways through the protein factors TFEB and FOXO1. Here we review various mechanisms of the neuroprotective action of trehalose and touch on the possibility of pleiotropic effects. Current knowledge about specific features of trehalose pharmacodynamics is discussed. The neuroprotective effects of trehalose in animal models of major neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases are examined too. Attention is given to translational transition to clinical trials of this drug, especially oral and parenteral routes of administration. Besides, the possibility of enhancing the therapeutic benefit via a combination of mTOR-dependent and mTOR-independent autophagy inducers is analyzed. In general, trehalose appears to be a promising multitarget tool for the inhibition of experimental neurodegeneration and requires thorough investigation of its clinical capabilities.

Impairment of autophagy after spinal cord injury potentiates neuroinflammation and motor function deficit in mice

Autophagy is a catabolic process that degrades cytoplasmic constituents and organelles in the lysosome, thus serving an important role in cellular homeostasis and protection against insults. We previously reported that defects in autophagy contribute to neuronal cell damage in traumatic spinal cord injury (SCI). Recent data from other inflammatory models implicate autophagy in regulation of immune and inflammatory responses, with low levels of autophagic flux associated with pro-inflammatory phenotypes. In the present study, we examined the effects of genetically or pharmacologically manipulating autophagy on posttraumatic neuroinflammation and motor function after SCI in mice. Methods: Young adult male C57BL/6, CX3CR1-GFP, autophagy hypomorph Becn1+/- mice, and their wildtype (WT) littermates were subjected to moderate thoracic spinal cord contusion. Neuroinflammation and autophagic flux in the injured spinal cord were assessed using flow cytometry, immunohistochemistry, and NanoString gene expression analysis. Motor function was evaluated with the Basso Mouse Scale and horizontal ladder test. Lesion volume and spared white matter were evaluated by unbiased stereology. To stimulate autophagy, disaccharide trehalose, or sucrose control, was administered in the drinking water immediately after injury and for up to 6 weeks after SCI. Results: Flow cytometry demonstrated dysregulation of autophagic function in both microglia and infiltrating myeloid cells from the injured spinal cord at 3 days post-injury. Transgenic CX3CR1-GFP mice revealed increased autophagosome formation and inhibition of autophagic flux specifically in activated microglia/macrophages. NanoString analysis using the neuroinflammation panel demonstrated increased expression of proinflammatory genes and decreased expression of genes related to neuroprotection in Becn1+/- mice as compared to WT controls at 3 days post-SCI. These findings were further validated by qPCR, wherein we observed significantly higher expression of proinflammatory cytokines. Western blot analysis confirmed higher protein expression of the microglia/macrophage marker IBA-1, inflammasome marker, NLRP3, and innate immune response markers cGAS and STING in Becn1+/- mice at 3 day after SCI. Flow cytometry demonstrated that autophagy deficit did not affect either microglial or myeloid counts at 3 days post-injury, instead resulting in increased microglial production of proinflammatory cytokines. Finally, locomotor function showed significantly worse impairments in Becn1+/- mice up to 6 weeks after SCI, which was accompanied by worsening tissue damage. Conversely, treatment with a naturally occurring autophagy inducer trehalose, reduced protein levels of p62, an adaptor protein targeting cargo to autophagosomes as well as the NLRP3, STING, and IBA-1 at 3 days post-injury. Six weeks of trehalose treatment after SCI led to improved motor function recovery as compared to control group, which was accompanied by reduced tissue damage. Conclusions: Our data indicate that inhibition of autophagy after SCI potentiates pro-inflammatory activation in microglia and is associated with worse functional outcomes. Conversely, increasing autophagy with trehalose, decreased inflammation and improved outcomes. These findings highlight the importance of autophagy in spinal cord microglia and its role in secondary injury after SCI.

Role of Mitophagy in neurodegenerative Diseases and potential tagarts for Therapy

Mitochondria dysfunction has been defined as one of the hallmarks of aging-related diseases as is characterized by the destroyed integrity, abnormal distribution and size, insufficient ATP supply, increased ROS production, and subsequently damage and oxidize the proteins, lipids and nucleic acid. Mitophagy, an efficient way of removing damaged or defective mitochondria by autophagy, plays a pivotal role in maintaining the mitochondrial quantity and quality control enabling the degradation of unwanted mitochondria, and thus rescues cellular homeostasis in response to stress. Accumulating evidence demonstrates that impaired mitophagy has been associated with many neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) in a variety of patients and disease models with neural death, oxidative stress and disturbed metabolism, either as the cause or consequence. These findings suggest that modulation of mitophagy may be considered as a valid therapeutic strategy in neurodegenerative diseases. In this review, we summarize recent findings on the mechanisms of mitophagy and its role in neurodegenerative diseases, with a particular focus on mitochondrial proteins acting as receptors that mediate mitophagy in these diseases.

Trehalose-releasing nanogels: A step toward a trehalose delivery vehicle for autophagy stimulation

Trehalose has been widely studied as a treatment for a variety of human disorders due to its ability to stimulate autophagy. Trehalose, however, is poorly adsorbed and is hydrolyzed in the intestinal mucosa, and oral delivery requires relatively high doses to induce autophagy. The parenteral injection of trehalose-releasing nanogels proposed in this study offers an alternative mode of delivery. This study aimed to develop stable colloidal dispersions of trehalose-rich nanogels that could sustainably release trehalose under physiologically relevant conditions. The nanogel design was based on the covalent incorporation of 6-O-acryloyl-trehalose within a polymer network. A series of nine trehalose-rich nanogels with highly conjugated trehalose (up to 59 % w/w) were synthesized and shown to sustainably release trehalose at a rate that is not dose dependent. The nanogels were optimized to keep colloidal stability in serum-enriched cell culture media. The stable nanogels were not cytotoxic to primary HUVECs. Two selected nanogels with opposite surface charges were subjected to extended in vitro characterization that included a cellular uptake study and a hemocompatibility assay. Both nanogels were efficiently taken up by HUVECs during a short incubation. They also proved not to be hemolytic to human RBCs in concentrations up to 2.0 mg/mL. Finally, an in vivo autophagy stimulation study employing transgenic zebrafish and Drosophila larvae demonstrated that prolonged exposure to a cationic trehalose-releasing nanogel can induce autophagic activity in in vivo systems without any detectable toxicity.

Preconditioning with Trehalose Protects the Bone Marrow-Derived Mesenchymal Stem Cells Under Oxidative Stress and Enhances the Stem Cell-Based Therapy for Cerebral Ischemic Stroke

Bone marrow-derived mesenchymal stem cell (BMSC) transplantation has emerged as a potential treatment for ischemic stroke. Preconditioning with pharmacological agents before cell transplantation has been shown to increase the efficiency of cell therapy. In this study, trehalose (Tre), an autophagy inducer, was used as a pharmacological agent to treat BMSCs, and the neuroprotective effect of BMSCs preconditioned with Tre on cerebral ischemia was assessed. BMSCs were treated in vitro with different concentrations of Tre. Immunofluorescence staining of LC3B was performed to detect autophagy, and Western blotting for LC3, Beclin1, p-AMPK, and p-mTOR was performed. Flow cytometry and Western blotting analysis were performed to measure cell apoptosis in the presence of hydrogen peroxide (H₂O₂). Enzyme-linked immunosorbent assay was used to test the secretion levels of neurotrophic factors. An in vivo ischemia/reperfusion model was generated by middle cerebral artery occlusion in male Sprague Dawley rats, and Tre-preconditioned BMSCs were administered intralesionally 24 hours after ischemic injury. Histopathological examination and neurological function studies were conducted. In vitro, Tre promotes autophagy of BMSCs through the activation of the AMPK signal pathway. Tre protected BMSCs from H₂O₂-induced cell viability reduction and apoptosis. Moreover, Tre pretreatment increased the secretion of brain-derived neurotrophic factor, vascular endothelial growth factor, and hepatocyte growth factor. In vivo, preconditioning with Tre could further enhance the survival of BMSCs, reduce infarct size, alleviate cell apoptosis, abate vessel decrease, and ultimately improve functional recovery. Our study indicates that Tre can enhance the survival of BMSCs under oxidative stress and enhance BMSC-based treatment of ischemia/reperfusion injury.

The Interplay Between Autophagy and RNA Homeostasis: Implications for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia

Amyotrophic lateral sclerosis and frontotemporal dementia are neurodegenerative disorders that lie on a disease spectrum, sharing genetic causes and pathology, and both without effective therapeutics. Two pathways that have been shown to play major roles in disease pathogenesis are autophagy and RNA homeostasis. Intriguingly, there is an increasing body of evidence suggesting a critical interplay between these pathways. Autophagy is a multi-stage process for bulk and selective clearance of malfunctional cellular components, with many layers of regulation. Although the majority of autophagy research focuses on protein degradation, it can also mediate RNA catabolism. ALS/FTD-associated proteins are involved in many stages of autophagy and autophagy-mediated RNA degradation, particularly converging on the clearance of persistent pathological stress granules. In this review, we will summarise the progress in understanding the autophagy-RNA homeostasis interplay and how that knowledge contributes to our understanding of the pathobiology of ALS/FTD.

Trehalose induces B cell autophagy to alleviate myocardial injury via the AMPK/ULK1 signalling pathway in acute viral myocarditis induced by Coxsackie virus B3

Viral myocarditis (VMC) is the main cause of sudden acute heart failure and cardiac death in adolescents; however, treatment for VMC is limited. Trehalose is a natural non-reductive disaccharide that protects against cardiovascular diseases by inducing autophagy. The protective effect of trehalose on VMC and the specific mechanism remains unclear. In this study, we established a VMC mouse model, treated with trehalose in vivo, and cultured B cells from VMC mice with trehalose in vitro to elucidate the effect of trehalose on B cells in acute VMC. Trehalose alleviated myocardial injury in VMC mice and increased the number of autophagosomes, LC3II/LC3I ratio, and expression level of LAMP2, whereas it decreased the expression of p62 in VMC-B cells. Bafilomycin A1 suppressed VMC-B cell autophagy induced by trehalose. At the mechanistic level, trehalose treatment significantly upregulated the phosphorylation of AMPK and ULK1 in VMC-B cells. Dorsomorphin and SBI-0206965 abolished the increased phosphorylation level and altered the expression levels of autophagy-related proteins. In conclusion, trehalose alleviates myocardial inflammatory damage of VMC by inducing B cell autophagy, mediated by the AMPK/ULK1 signalling pathway. Thus, trehalose may be a potentially useful molecule for alleviating myocardial injury in VMC.

Functional and transcriptional profiling of microglial activation during the chronic phase of TBI identifies an age-related driver of poor outcome in old mice

Elderly patients with traumatic brain injury (TBI) have greater mortality and poorer outcomes than younger individuals. The extent to which old age alters long-term recovery and chronic microglial activation after TBI is unknown, and evidence for therapeutic efficacy in aged mice is sorely lacking. The present study sought to identify potential inflammatory mechanisms underlying age-related outcomes late after TBI. Controlled cortical impact was used to induce moderate TBI in young and old male C57BL/6 mice. At 12 weeks post-injury, aged mice exhibited higher mortality, poorer functional outcomes, larger lesion volumes, and increased microglial activation. Transcriptomic analysis identified age- and TBI-specific gene changes consistent with a disease-associated microglial signature in the chronically injured brain, including those involved with complement, phagocytosis, and autophagy pathways. Dysregulation of phagocytic and autophagic function in microglia was accompanied by increased neuroinflammation in old mice. As proof-of-principle that these pathways have functional importance, we administered an autophagic enhancer, trehalose, in drinking water continuously for 8 weeks after TBI. Old mice treated with trehalose showed enhanced functional recovery and reduced microglial activation late after TBI compared to the sucrose control group. Our data indicate that microglia undergo chronic changes in autophagic regulation with both normal aging and TBI that are associated with poorer functional outcome. Enhancing autophagy may therefore be a promising clinical therapeutic strategy for TBI, especially in older patients.

Mitophagy and Neurodegeneration: Between the Knowns and the Unknowns

Macroautophagy (henceforth autophagy) an evolutionary conserved intracellular pathway, involves lysosomal degradation of damaged and superfluous cytosolic contents to maintain cellular homeostasis. While autophagy was initially perceived as a bulk degradation process, a surfeit of studies in the last 2 decades has revealed that it can also be selective in choosing intracellular constituents for degradation. In addition to the core autophagy machinery, these selective autophagy pathways comprise of distinct molecular players that are involved in the capture of specific cargoes. The diverse organelles that are degraded by selective autophagy pathways are endoplasmic reticulum (ERphagy), lysosomes (lysophagy), mitochondria (mitophagy), Golgi apparatus (Golgiphagy), peroxisomes (pexophagy) and nucleus (nucleophagy). Among these, the main focus of this review is on the selective autophagic pathway involved in mitochondrial turnover called mitophagy. The mitophagy pathway encompasses diverse mechanisms involving a complex interplay of a multitude of proteins that confers the selective recognition of damaged mitochondria and their targeting to degradation via autophagy. Mitophagy is triggered by cues that signal the mitochondrial damage such as disturbances in mitochondrial fission-fusion dynamics, mitochondrial membrane depolarisation, enhanced ROS production, mtDNA damage as well as developmental cues such as erythrocyte maturation, removal of paternal mitochondria, cardiomyocyte maturation and somatic cell reprogramming. As research on the mechanistic aspects of this complex pathway is progressing, emerging roles of new players such as the NIPSNAP proteins, Miro proteins and ER-Mitochondria contact sites (ERMES) are being explored. Although diverse aspects of this pathway are being investigated in depth, several outstanding questions such as distinct molecular players of basal mitophagy, selective dominance of a particular mitophagy adapter protein over the other in a given physiological condition, molecular mechanism of how specific disease mutations affect this pathway remain to be addressed. In this review, we aim to give an overview with special emphasis on molecular and signalling pathways of mitophagy and its dysregulation in neurodegenerative disorders.

Carrier-Free Trehalose-Based Nanomotors Targeting Macrophages in Inflammatory Plaque for Treatment of Atherosclerosis

Inducing autophagy of macrophages to improve abnormal lipid metabolism is an important way to treat atherosclerosis (AS). Yet, the current application of the mammalian target of rapamycin (mTOR)-dependent autophagy inducers is limited by the side effects and lack of targeting and low biological availability. Herein, a kind of nitric oxide (NO)-driven carrier-free nanomotor based on the reaction between trehalose (Tr, one of the mTOR-independent autophagy inducers), L-arginine (Arg), and phosphatidylserine (PS) is reported. The developed nanomotors use NO as the driving force, which is generated from the reaction between Arg and excessive reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS) specifically presenting in the AS microenvironment. The high expression of ROS and iNOS in the AS site can be used as chemoattractants to induce chemotaxis behavior of the nanomotors to achieve the first-step targeting an AS plaque. Subsequently, the "eat me" signal sent by PS is exploited to precisely target to the macrophages in the AS plaque, realizing the plaque-macrophage-targeted effect by this step-by-step strategy. In vitro and in vivo results confirm that the introduction of the concept of carrier-free nanomotors has greatly improved the biological availability of trehalose (the dose can be reduced from 2.5 g kg^-1 in previous reports to 0.01 g kg^-1 in this work). Particularly, consumed ROS and the production of NO during the targeting process also play positive roles, in which the former regulates the M2 polarization of macrophages and the latter promotes the reconstruction of an endothelial barrier, which contributes to the multilink treatment of AS.

Deciphering therapeutic options for neurodegenerative diseases: insights from SIRT1

Silent information regulator 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD +)-dependent protein deacetylase that exerts biological effects through nucleoplasmic transfer. Recent studies have highlighted that SIRT1 deacetylates protein substrates to exert its neuroprotective effects, including decreased oxidative stress and inflammatory, increases autophagy, increases levels of nerve growth factors (correlated with behavioral changes), and maintains neural integrity (affects neuronal development and function) in aging or neurological disorder. In this review, we highlight the molecular mechanisms underlying the protective role of SIRT1 in modulating neurodegeneration, focusing on protein homeostasis, aging-related signaling pathways, neurogenesis, and synaptic plasticity. Meanwhile, the potential of targeting SIRT1 to block the occurrence and progression of neurodegenerative diseases is also discussed. Taken together, this review provides an up-to-date evaluation of our current understanding of the neuroprotective mechanisms of SIRT1 and also be involved in the potential therapeutic opportunities of AD and related neurodegenerative diseases.

Neuroprotective effects of naturally sourced bioactive polysaccharides: an update

Polysaccharides are macromolecular complexes that have various biological activities. In vivo and in vitro studies have shown that polysaccharides play neuroprotective roles through multiple mechanisms; consequently, they have potential in the prevention and treatment of neurodegenerative diseases. This paper summarizes related research published during 2015-2020 and reviews advances in the understanding of the neuroprotective effects of bioactive polysaccharides. This review focuses on 15 bioactive polysaccharides from plants and fungi that have neuroprotective properties against oxidative stress, apoptosis, neuroinflammation, and excitatory amino acid toxicity mainly through the regulation of nuclear factor kappa-B, phosphatidylinositol-3-kinase/protein kinase B, mitogen-activated protein kinase, nuclear factor-E2-related factor 2/ hemeoxygenase-1, c-jun N-terminal kinase, protein kinase B-mammalian target of rapamycin, and reactive oxygen species-nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 signaling pathways. Natural bioactive polysaccharides have potential in the prevention and treatment of neurodegenerative diseases because of their advantageous characteristics, including multi-targeting, low toxicity, and synergistic effects. However, most of the recent related research has focused on cell and animal models. Future randomized clinical trials involving large sample sizes are needed to validate the therapeutic benefits of these neuroprotective polysaccharides in patients having neurodegenerative diseases.

Regulation of neuronal autophagy and the implications in neurodegenerative diseases

Neurons are highly polarized and post-mitotic cells with the specific requirements of neurotransmission accompanied by high metabolic demands that create a unique challenge for the maintenance of cellular homeostasis. Thus, neurons rely heavily on autophagy that constitutes a key quality control system by which dysfunctional cytoplasmic components, protein aggregates, and damaged organelles are sequestered within autophagosomes and then delivered to the lysosome for degradation. While mature lysosomes are predominantly located in the soma of neurons, the robust, constitutive biogenesis of autophagosomes occurs in the synaptic terminal via a conserved pathway that is required to maintain synaptic integrity and function. Following formation, autophagosomes fuse with late endosomes and then are rapidly and efficiently transported by the microtubule-based cytoplasmic dynein motor along the axon toward the soma for lysosomal clearance. In this review, we highlight the recent knowledge of the roles of autophagy in neuronal health and disease. We summarize the available evidence about the normal functions of autophagy as a protective factor against neurodegeneration and discuss the mechanism underlying neuronal autophagy regulation. Finally, we describe how autophagy function is affected in major neurodegenerative diseases with a special focus on Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis.

Role of Glia-Derived Extracellular Vesicles in Neurodegenerative Diseases

Extracellular vesicles (EVs), as nano-sized vesicles secreted by almost all cells, have been recognized as the essential transmitter for cell-to-cell communication and participating in multiple biological processes. Neurodegenerative diseases (ND), such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis, share common mechanisms of the aggregation and propagation of distinct pathologic proteins among cells in the nervous systems and neuroinflammatory reactions mediated by glia during the pathogenic process. This feature indicates the vital role of crosstalk between neurons and glia in the pathogenesis of ND. In recent years, glia-derived EVs have been investigated as potential mediators of signals between neurons and glia, which provides a new direction and strategy for understanding ND. By a comprehensive summary, it can be concluded that glia-derived EVs have both a beneficial and/or a detrimental effect in the process of ND. Therefore, this review article conveys the role of glia-derived EVs in the pathogenesis of ND and raises current limitations of their potential application in the diagnosis and treatment of ND.

A Novel Supplement Attenuates Oxidative Stress-Induced TDP-43-Related Pathogenesis in TDP-43-Expressed Cells

Amyotrophic lateral sclerosis (ALS) is caused by selective the loss of spinal motor neurons by multifactorial pathological mechanisms and results in muscle atrophy. Incidence rates of ALS are increasing over time, but there are no effective treatments at present due to limitations on approved therapies (riluzole and edaravone). Therefore, this study investigated whether combined treatment with Bojungikgi-tang and riluzole could act synergistically in transactive response DNA-binding protein 43 (TDP-43) stress granule cells. To examine the effect of combined treatment on oxidative stress-induced cell death, the CCK8 assay was performed for the detection of cell viability. The expression of oxidative stress-induced proteins was determined by Western blot. Quantification of sodium arsenite-induced reactive oxygen species (ROS) was measured in TDP-43 stress granular cells using 2,7-diacetyl dichlorofluorescein diacetate. To investigate the effect of combined treatment on TDP-43 aggregation, immunofluorescence and immunoblotting were performed in TDP-43 stress granular cells. This combined treatment alleviated oxidative stress-induced cell death by increasing the expression levels of antioxidation proteins, such as heme oxygenase-1 and B cell lymphoma-2-associated X protein. Furthermore, it reduced oxidative stress-induced TDP-43 aggregates and lowered the levels of autophagy-related proteins, including p62, light chain 3b, and ATG8, in TDP-43-expressing cells. Our results suggest that this combined treatment could be helpful for autophagy regulation in other neurodegenerative diseases.

Amyotrophic lateral sclerosis alters the metabolic aging profile in patient derived fibroblasts

Aging is a major risk factor for neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). As metabolic alterations are a hallmark of aging and have previously been observed in ALS, it is important to examine the effect of aging in the context of ALS metabolic function. Here, using a newly established phenotypic metabolic approach, we examined the effect of aging on the metabolic profile of fibroblasts derived from ALS cases compared to controls. We found that ALS fibroblasts have an altered metabolic profile, which is influenced by age. In control cases, we found significant increases with age in NADH metabolism in the presence of several metabolites including lactic acid, trehalose, uridine and fructose, which was not recapitulated in ALS cases. Conversely, we found a reduction of NADH metabolism with age of biopsy, age of onset and age of death in the presence of glycogen in the ALS cohort. Furthermore, we found that NADH production correlated with disease progression rates in relation to a number of metabolites including inosine and α-ketoglutaric acid. Inosine or α-ketoglutaric acid supplementation in ALS fibroblasts was bioenergetically favourable. Overall, we found aging related defects in energy substrates that feed carbon into glycolysis at various points as well as the tricarboxylic acid (TCA) cycle in ALS fibroblasts, which was validated in induced neuronal progenitor cell derived iAstrocytes. Our results suggest that supplementing those pathways may protect against age related metabolic dysfunction in ALS.