Oxidative stress, mitochondrial and proteostasis malfunction in adrenoleukodystrophy: A paradigm for axonal degeneration

Easily misdiagnosed X-linked adrenoleukodystrophy

BACKGROUND

Addison's disease and X-linked adrenoleukodystrophy (X-ALD) (Addison's-only) are two diseases that need to be identified. Addison's disease is easy to diagnose clinically when only skin and mucosal pigmentation symptoms are present. However, X-ALD (Addison's-only) caused by ABCD1 gene variation is ignored, thus losing the opportunity for early treatment. This study described two patients with initial clinical diagnosis of Addison's disease. However, they rapidly developed neurological symptoms triggered by infection. After further genetic testing, the two patients were diagnosed with X-ALD.

METHODS

We retrospectively analyzed X-ALD patients admitted to our hospital. Clinical features, laboratory test results, and imaging data were collected. Whole-exome sequencing was used in molecular genetics.

RESULTS

Two patients were included in this study. Both of them had significantly increased adrenocorticotropic hormone level and skin and mucosal pigmentation. They were initially clinically diagnosed with Addison's disease and received hydrocortisone treatment. However, both patients developed progressive neurological symptoms following infectious disease. Further brain magnetic resonance imaging was completed, and the results suggested demyelinating lesions. Molecular genetics suggested variations in the ABCD1 gene, which were c.109_110insGCCA (p.C39Pfs*156), c.1394-2 A > C (NM_000033), respectively. Therefore, the two patients were finally diagnosed with X-ALD, whose classification had progressed from X-ALD (Addison's-only) to childhood cerebral adrenoleukodystrophy (CCALD). Moreover, the infection exacerbates the demyelinating lesions and accelerates the onset of neurological symptoms. Neither the two variation sites in this study had been previously reported, which extends the ABCD1 variation spectrum.

CONCLUSIONS

Patients with only symptoms of adrenal insufficiency cannot be simply clinically diagnosed with Addison's disease. Being alert to the possibility of ABCD1 variation is necessary, and complete genetic testing is needed as soon as possible to identify X-ALD (Addison's-only) early to achieve regular monitoring of the disease and receive treatment early. In addition, infection, as a hit factor, may aggravate demyelinating lesions of CCALD. Thus, patients should be protected from external environmental factors to delay the progression of cerebral adrenoleukodystrophy.

Imbalanced mitochondrial dynamics contributes to the pathogenesis of X-linked adrenoleukodystrophy

The peroxisomal disease adrenoleukodystrophy (X-ALD) is caused by loss of the transporter of very-long-chain fatty acids (VLCFAs), ABCD1. An excess of VLCFAs disrupts essential homeostatic functions crucial for axonal maintenance, including redox metabolism, glycolysis and mitochondrial respiration. As mitochondrial function and morphology are intertwined, we set out to investigate the role of mitochondrial dynamics in X-ALD models. Using quantitative 3D transmission electron microscopy, we revealed mitochondrial fragmentation in corticospinal axons in Abcd1- mice. In patient fibroblasts, an excess of VLCFAs triggers mitochondrial fragmentation through the redox-dependent phosphorylation of DRP1 (DRP1S616). The blockade of DRP1-driven fission by the peptide P110 effectively preserved mitochondrial morphology. Furthermore, mRNA inhibition of DRP1 not only prevented mitochondrial fragmentation but also protected axonal health in a Caenorhabditis elegans model of X-ALD, underscoring DRP1 as a potential therapeutic target. Elevated levels of circulating cell-free mtDNA in patients' CSF align this leukodystrophy with primary mitochondrial disorders. Our findings underscore the intricate interplay between peroxisomal dysfunction, mitochondrial dynamics and axonal integrity in X-ALD, shedding light on potential avenues for therapeutic intervention.

Accelerated Course of Cerebral Adrenoleukodystrophy After Coronavirus Disease 2019 Infection

BACKGROUND

Coronavirus disease 2019 (COVID-19) can not only infect the respiratory system but also affect the nervous system through the release of inflammatory factors. Our study aimed to investigate the effect of COVID-19 infection on cerebral adrenoleukodystrophy (ALD).

METHODS

Changes in the neurological symptoms of cerebral ALD after infection with COVID-19 from January 2022 to February 2023 were retrospectively analyzed. The primary assessment indicator was the Neurologic Function Scale (NFS) score.

RESULTS

A total of 17 male patients with cerebral ALD were enrolled, with a median age of 101 months (80 to 151 months). Among them, 11 (11 of 17, 64.7%) developed an exacerbation of neurological symptoms after COVID-19 infection. Two patients with NFS = 0 started presenting with neurological symptoms after infection. Fifteen patients were in the advanced stage (NFS >1 and/or Loes score >9), of which nine did not progress to major functional disabilities (MFDs). Seven of the nine patients (77.8%) experienced an increase in NFS scores, ranging from 1 to 9 points, within two weeks of COVID-19 infection, with four of them experiencing MFDs. For the other six patients who had progressed to MFDs, there was not much room for further degeneration, so the NFS score did not increase after COVID-19 infection. No deaths related to COVID-19 infection occurred.

CONCLUSIONS

COVID-19 infection may aggravate neurological symptoms of cerebral ALD, particularly among patients who have not yet progressed to MFDs. Therefore, COVID-19 may accelerate the course of cerebral ALD, so protecting patients from infection is essential for maintaining the stability of the disease.

Generation and characterization of induced pluripotent stem cell lines derived from skin fibroblasts of patients with adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is a rare peroxisome disease with phenotypic heterogeneity. There is a lack of suitable in vitro models to study its pathogenesis. We established two strains of iPSCs from skin fibroblasts of patients with childhood cerebral ALD and Addison's disease, respectively. CytoTune™2.0 Sendai reprogramming kit was used. The iPSC lines showed typical stem cell morphology, normal karyotype, and carrying ABCD1 variation. The iPSC lines express pluripotency markers, and have the capacity to differentiate into three germ layers. iPSCs can be used as an alternative cell source for ALD in vitro model to study its pathogenesis and therapeutic strategies.

Abnormal activation of MAPKs pathways and inhibition of autophagy in a group of patients with Zellweger spectrum disorders and X-linked adrenoleukodystrophy

BACKGROUND

Zellweger spectrum disorders (ZSD) and X-linked adrenoleukodystrophy (X-ALD) are inherited metabolic diseases characterized by dysfunction of peroxisomes, that are essential for lipid metabolism and redox balance. Oxidative stress has been reported to have a significant role in the pathogenesis of neurodegenerative diseases such as peroxisomal disorders, but little is known on the intracellular activation of Mitogen-activated protein kinases (MAPKs). Strictly related to oxidative stress, a correct autophagic machinery is essential to eliminated oxidized proteins and damaged organelles. The aims of the current study are to investigate a possible implication of MAPK pathways and autophagy impairment as markers and putative therapeutic targets in X-ALD and ZSDs.

METHODS

Three patients with ZSD (2 M, 1 F; age range 8-17 years) and five patients with X-ALD (5 M; age range 5- 22 years) were enrolled. A control group included 6 healthy volunteers. To evaluate MAPKs pathway, p-p38 and p-JNK were assessed by western blot analysis on peripheral blood mononuclear cells. LC3II/LC3I ratio was evaluated ad marker of autophagy.

RESULTS

X-ALD and ZSD patients showed elevated p-p38 values on average 2- fold (range 1.21- 2.84) and 3.30-fold (range 1.56- 4.26) higher when compared with controls, respectively. p-JNK expression was on average 12-fold (range 2.20-19.92) and 2.90-fold (range 1.43-4.24) higher in ZSD and X-ALD patients than in controls. All patients had altered autophagic flux as concluded from the reduced LC3II/I ratio.

CONCLUSIONS

In our study X-ALD and ZSD patients present an overactivation of MAPK pathways and an inhibition of autophagy. Considering the absence of successful therapies and the growing interest towards new therapies with antioxidants and autophagy inducers, the identification and validation of biomarkers to monitor optimal dosing and biological efficacy of the treatments is of prime interest.

Exploratory study of autophagy inducer sirolimus for childhood cerebral adrenoleukodystrophy

Objectives

X-linked adrenoleukodystrophy (ALD) is a peroxisomal disease caused by mutations in the ABCD1 gene. Childhood cerebral ALD (CCALD) is characterized by inflammatory demyelination, rapidly progressing, often fatal. Hematopoietic stem cell transplant only delays disease progression in patients with early-stage cerebral ALD. Based on emergency humanitarianism, this study aims to investigate the safety and efficacy of sirolimus in the treatment of patients with CCALD.

Methods

This was a prospective, single-center, one-arm clinical trial. We enrolled patients with CCALD, and all enrolled patients received sirolimus treatment for three months. Adverse events were monitored and recorded to evaluate the safety. The efficacy was evaluated using the neurologic function scale (NFS), Loes score, and white matter hyperintensities.

Results

A total of 12 patients were included and all presented with CCALD. Four patients dropped out and a total of eight patients in the advanced stage completed a 3-month follow-up. There were no serious adverse events, and the common adverse events were hypertonia and oral ulcers. After sirolimus treatment, three of the four patients with an initial NFS > 10 showed improvements in their clinical symptoms. Loes scores decreased by 0.5-1 point in two of eight patients and remained unchanged in one patient. Analysis of white matter hyperintensities revealed a significant decrease in signal intensity (n = 7, p = 0.0156).

Conclusions

Our study suggested that autophagy inducer sirolimus is safe for CCALD. Sirolimus did not improve clinical symptoms of patients with advanced CCALD significantly. Further study with larger sample size and longer follow-up is needed to confirm the drug efficacy.Clinical Trial registration: https://www.chictr.org.cn/historyversionpuben.aspx, identifier ChiCTR1900021288.

The AMPK-dependent inhibition of autophagy plays a crucial role in protecting photoreceptor from photooxidative injury

Excessive light exposure can potentially cause irreversible damage to the various photoreceptor cells, and this aspect has been considered as an important factor leading to the progression of the different retinal diseases. AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR) are crucial intracellular signaling hubs involved in the regulation of cellular metabolism, energy homeostasis, cellular growth and autophagy. A number of previous studies have indicated that either AMPK activation or mTOR inhibition can promote autophagy in most cases. In the current study, we have established an in vitro as well as in vivo photooxidation-damaged photoreceptor model and investigated the possible influence of visible light exposure in the AMPK/mTOR/autophagy signaling pathway. We have also explored the potential regulatory effects of AMPK/mTOR on light-induced autophagy and protection achieved by suppressing autophagy in photooxidation-damaged photoreceptors. We observed that light exposure led to a significant activation of mTOR and autophagy in the photoreceptor cells. However, intriguingly, AMPK activation or mTOR inhibition significantly inhibited rather than promoting autophagy, which was termed as AMPK-dependent inhibition of autophagy. In addition, either indirectly suppressing autophagy by AMPK activation/ mTOR inhibition or directly blocking autophagy with an inhibitor exerted a significant protective effect on the photoreceptor cells against the photooxidative damage. Neuroprotective effects caused by the AMPK-dependent inhibition of autophagy were also verified with a retinal light injured mouse model in vivo. Overall, our findings demonstrated that AMPK / mTOR pathway could inhibit autophagy through AMPK-dependent inhibition of autophagy to significantly protect the photoreceptors from photooxidative injury, which may aid to further develop novel targeted retinal neuroprotective drugs.

Targeted Brain Delivery of Dendrimer-4-Phenylbutyrate Ameliorates Neurological Deficits in a Long-Term ABCD1-Deficient Mouse Model of X-Linked Adrenoleukodystrophy

X-linked adrenoleukodystrophy (ALD) is a genetic disorder that presents neurologically as either a rapid and fatal cerebral demyelinating disease in childhood (childhood cerebral adrenoleukodystrophy; ccALD) or slow degeneration of the spinal cord in adulthood (adrenomyeloneuropathy; AMN). All forms of ALD result from mutations in the ATP Binding Cassette Subfamily D Member (ABCD) 1 gene, encoding a peroxisomal transporter responsible for the import of very long chain fatty acids (VLCFA) and results mechanistically in a complex array of dysfunction, including endoplasmic reticulum stress, oxidative stress, mitochondrial dysfunction, and inflammation. Few therapeutic options exist for these patients; however, an additional peroxisomal transport protein (ABCD2) has been successfully targeted previously for compensation of dysfunctional ABCD1. 4-Phenylbutyrate (4PBA), a potent activator of the ABCD1 homolog ABCD2, is FDA approved, but use for ALD has been stymied by a short half-life and thus a need for unfeasibly high doses. We conjugated 4PBA to hydroxyl polyamidoamine (PAMAM) dendrimers (D-4PBA) to a create a long-lasting and intracellularly targeted approach which crosses the blood-brain barrier to upregulate Abcd2 and its downstream pathways. Across two studies, Abcd1 knockout mice administered D-4PBA long term showed neurobehavioral improvement and increased Abcd2 expression. Furthermore, when the conjugate was administered early, significant reduction of VLCFA and improved survival of spinal cord neurons was observed. Taken together, these data show improved efficacy of D-4PBA compared to previous studies of free 4PBA alone, and promise for D-4PBA in the treatment of complex and chronic neurodegenerative diseases using a dendrimer delivery platform that has shown successes in recent clinical trials. While recovery in our studies was partial, combined therapies on the dendrimer platform may offer a safe and complete strategy for treatment of ALD.

The physiological functions of human peroxisomes

Peroxisomes are subcellular organelles that play a central role in human physiology by catalyzing a range of unique metabolic functions. The importance of peroxisomes for human health is exemplified by the existence of a group of usually severe diseases caused by an impairment in one or more peroxisomal functions. Among others these include the Zellweger spectrum disorders, X-linked adrenoleukodystrophy, and Refsum disease. To fulfill their role in metabolism, peroxisomes require continued interaction with other subcellular organelles including lipid droplets, lysosomes, the endoplasmic reticulum, and mitochondria. In recent years it has become clear that the metabolic alliance between peroxisomes and other organelles requires the active participation of tethering proteins to bring the organelles physically closer together, thereby achieving efficient transfer of metabolites. This review intends to describe the current state of knowledge about the metabolic role of peroxisomes in humans, with particular emphasis on the metabolic partnership between peroxisomes and other organelles and the consequences of genetic defects in these processes. We also describe the biogenesis of peroxisomes and the consequences of the multiple genetic defects therein. In addition, we discuss the functional role of peroxisomes in different organs and tissues and include relevant information derived from model systems, notably peroxisomal mouse models. Finally, we pay particular attention to a hitherto underrated role of peroxisomes in viral infections.

Antioxidant Response in Human X-Linked Adrenoleukodystrophy Fibroblasts

Redox imbalance, mitochondrial dysfunction, and inflammation play a major role in the pathophysiology of X-linked adrenoleukodystrophy (X-ALD), an inherited neurodegenerative disease caused by mutations in the ABCD1 gene, encoding the protein responsible for peroxisomal import and degradation of very long chain fatty acids (VLCFAs). Therefore, VLCFAs accumulate in tissues and plasma, constituting a pathognomonic biomarker for diagnosis. However, the precise role of VLCFA accumulation on the diverse clinical phenotypes of X-ALD and the pathogenic link between VLCFAs and oxidative stress remain currently unclear. This study proposes ferroptosis as a crucial contributor to the disease development and progression. The expression profiles of "GPX4-glutathione" and "NQO1-CoQ₁₀" ferroptosis pathways have been analyzed in fibroblasts of one patient with AMN, the late onset and slowly progressive form of X-ALD, and in two patients with cALD, the cerebral inflammatory demyelinating form of early childhood. Furthermore, as no effective treatments are currently available, especially for the rapidly progressing form of X-ALD (cALD), the efficacy of NAC treatment has also been evaluated to open the way toward novel combined therapies. Our findings demonstrate that lipid peroxides accumulate in X-ALD fibroblasts and ferroptosis-counteracting enzymes are dysregulated, highlighting a different antioxidant response in patients with AMN and cALD.

Activating cannabinoid receptor 2 preserves axonal health through GSK-3β/NRF2 axis in adrenoleukodystrophy

Aberrant endocannabinoid signaling accompanies several neurodegenerative disorders, including multiple sclerosis. Here, we report altered endocannabinoid signaling in X-linked adrenoleukodystrophy (X-ALD), a rare neurometabolic demyelinating syndrome caused by malfunction of the peroxisomal ABCD1 transporter, resulting in the accumulation of very long-chain fatty acids (VLCFAs). We found abnormal levels of cannabinoid receptor 2 (CB2r) and related endocannabinoid enzymes in the brain and peripheral blood mononuclear cells (PBMCs) of X-ALD patients and in the spinal cord of a murine model of X-ALD. Preclinical treatment with a selective agonist of CB2r (JWH133) halted axonal degeneration and associated locomotor deficits, along with normalization of microgliosis. Moreover, the drug improved the main metabolic disturbances underlying this model, particularly in redox and lipid homeostatic pathways, including increased lipid droplets in motor neurons, through the modulation of the GSK-3β/NRF2 axis. JWH133 inhibited Reactive Oxygen Species elicited by excess VLCFAs in primary microglial cultures of Abcd1-null mice. Furthermore, we uncovered intertwined redox and CB2r signaling in the murine spinal cords and in patient PBMC samples obtained from a phase II clinical trial with antioxidants (NCT01495260). These findings highlight CB2r signaling as a potential therapeutic target for X-ALD and perhaps other neurodegenerative disorders that present with dysregulated redox and lipid homeostasis.

The Role of Oxidative Stress and Inflammation in X-Link Adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited disease caused by a mutation in the ABCD1 gene encoding a peroxisomal transmembrane protein. It is characterized by the accumulation of very-long-chain fatty acids (VLCFAs) in body fluids and tissues, leading to progressive demyelination and adrenal insufficiency. ALD has various phenotypes, among which the most common and severe is childhood cerebral adrenoleukodystrophy (CCALD). The pathophysiological mechanisms of ALD remain unclear, but some in vitro/in vivo research showed that VLCFA could induce oxidative stress and inflammation, leading to damage. In addition, the evidence that oxidative stress and inflammation are increased in patients with X-ALD also proves that it is a potential mechanism of brain and adrenal damage. Therefore, normalizing the redox balance becomes a critical therapeutic target. This study focuses on the possible predictors of the severity and progression of X-ALD, the potential mechanisms of pathogenesis, and the promising targeted drugs involved in oxidative stress and inflammation.

Therapeutic potential of resveratrol in diabetic nephropathy according to molecular signaling

BACKGROUND

Diabetic nephropathy (DN) as a severe complication of diabetes mellitus (DM), is a crucial menace for human health and survival and remarkably elevates the healthcare systems' costs. Therefore, it is worth noting to identify novel preventive and therapeutic strategies to alleviate the disease conditions. Resveratrol, as a well-defined anti-diabetic/ antioxidant agent has capabilities to counteract diabetic complications. It has been predicted that resveratrol will be a fantastic natural polyphenol for diabetes therapy in the next few years.

OBJECTIVE

Accordingly, the current review aims to depict the role of resveratrol in the regulation of different signaling pathways that are involved in the reactive oxygen species (ROS) production, inflammatory processes, autophagy, and mitochondrial dysfunction, as critical contributors to DN pathophysiology.

RESULTS

The pathogenesis of DN can be multifactorial; hyperglycemia is one of the prominent risk factors of DN development that is closely related to oxidative stress. Resveratrol, as a well-defined polyphenol, has various biological and medicinal properties, including anti-diabetic, anti-inflammatory, and anti-oxidative effects.

CONCLUSION

Resveratrol prevents kidney damages that are caused by oxidative stress, enhances antioxidant capacity, and attenuates the inflammatory and fibrotic responses. For this reason, resveratrol is considered an interesting target in DN research due to its therapeutic possibilities during diabetic disorders and renal protection.

The Peroxisome-Autophagy Redox Connection: A Double-Edged Sword?

Peroxisomes harbor numerous enzymes that can produce or degrade hydrogen peroxide (H2O2). Depending on its local concentration and environment, this oxidant can function as a redox signaling molecule or cause stochastic oxidative damage. Currently, it is well-accepted that dysfunctional peroxisomes are selectively removed by the autophagy-lysosome pathway. This process, known as "pexophagy," may serve a protective role in curbing peroxisome-derived oxidative stress. Peroxisomes also have the intrinsic ability to mediate and modulate H2O2-driven processes, including (selective) autophagy. However, the molecular mechanisms underlying these phenomena are multifaceted and have only recently begun to receive the attention they deserve. This review provides a comprehensive overview of what is known about the bidirectional relationship between peroxisomal H2O2 metabolism and (selective) autophagy. After introducing the general concepts of (selective) autophagy, we critically examine the emerging roles of H2O2 as one of the key modulators of the lysosome-dependent catabolic program. In addition, we explore possible relationships among peroxisome functioning, cellular H2O2 levels, and autophagic signaling in health and disease. Finally, we highlight the most important challenges that need to be tackled to understand how alterations in peroxisomal H2O2 metabolism contribute to autophagy-related disorders.

JAB1 deletion in oligodendrocytes causes senescence-induced inflammation and neurodegeneration in mice

Oligodendrocytes are the primary target of demyelinating disorders and progressive neurodegenerative changes may evolve in the CNS. DNA damage and oxidative stress are considered key pathogenic events, but the underlying molecular mechanisms remain unclear. Moreover, animal models do not fully recapitulate human diseases, complicating the path to effective treatments. Here we report that mice with cell autonomous deletion of the nuclear COP9 signalosome component CSN5 (JAB1) in oligodendrocytes develop DNA damage and defective DNA repair in myelinating glial cells. Interestingly, oligodendrocytes lacking JAB1 expression underwent a senescence-like phenotype that fostered chronic inflammation and oxidative stress. These mutants developed progressive CNS demyelination, microglia inflammation and neurodegeneration, with severe motor deficits and premature death. Notably, blocking microglia inflammation did not prevent neurodegeneration, whereas the deletion of p21CIP1 but not p16INK4a pathway ameliorated the disease. We suggest that senescence is key to sustaining neurodegeneration in demyelinating disorders and may be considered a potential therapeutic target.

ABCD1 and X-linked adrenoleukodystrophy: A disease with a markedly variable phenotype showing conserved neurobiology in animal models

X-linked adrenoleukodystrophy (X-ALD) is a phenotypically heterogeneous disorder involving defective peroxisomal β-oxidation of very long-chain fatty acids (VLCFAs), due to mutation in the ABCD1 gene. X-ALD is the most common peroxisomal inborn error of metabolism and confers a high degree of morbidity and mortality. Remarkably, a subset of patients exhibit a cerebral form with inflammatory invasion of the central nervous system and extensive demyelination, while in others only dying-back axonopathy or even isolated adrenal insufficiency is seen, without genotype-phenotype correlation. X-ALD's biochemical signature is marked elevation of VLCFAs in blood, a finding that has been utilized for massive newborn screening for early diagnosis. Investigational gene therapy approaches hold promises for improved outcomes. However, the pathophysiological mechanisms of the disease remain poorly understood, limiting investigation of targeted therapeutic options. Animal models for the disease recapitulate the biochemical signature of VLCFA accumulation and demonstrate mitochondrially generated reactive oxygen species, oxidative damage, increased glial death, and axonal damage. Most strikingly, however, cerebral invasion of leukocytes and demyelination were not observed in any animal model for X-ALD, reflecting upon pathological processes that are yet to be discovered. This review summarizes the current disease models in animals, the lessons learned from these models, and the gaps that remained to be filled in order to assist in therapeutic investigations for ALD.

Management of adrenoleukodystrophy: From pre-clinical studies to the development of new therapies

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurodegenerative disorder associated with mutations of the ABCD1 gene that encodes a peroxisomal transmembrane protein. It results in accumulation of very long chain fatty acids in tissues and body fluid. Along with other factors such as epigenetic and environmental involvement, ABCD1 mutation-provoked disorders can present different phenotypes including cerebral adrenoleukodystrophy (cALD), adrenomyeloneuropathy (AMN), and peripheral neuropathy. cALD is the most severe form that causes death in young childhood. Bone marrow transplantation and hematopoietic stem cell gene therapy are only effective when performed at an early stage of onsets in cALD. Nonetheless, current research and development of novel therapies are hampered by a lack of in-depth understanding disease pathophysiology and a lack of reliable cALD models. The Abcd1 and Abcd1/Abcd2 knock-out mouse models as well as the deficiency of Abcd1 rabbit models created in our lab, do not develop cALD phenotypes observed in human beings. In this review, we summarize the clinical and biochemical features of X-ALD, the progress of pre-clinical and clinical studies. Challenges and perspectives for future X-ALD studies are also discussed.

Translational and clinical pharmacology considerations in drug repurposing for X-linked adrenoleukodystrophy-A rare peroxisomal disorder

X-linked adrenoleukodystrophy (X-ALD) is an inherited, neurodegenerative rare disease that can result in devastating symptoms of blindness, gait disturbances and spastic quadriparesis due to progressive demyelination. Typically, the disease progresses rapidly, causing death within the first decade of life. With limited treatments available, efforts to determine an effective therapy that can alter disease progression or mitigate symptoms have been undertaken for many years, particularly through drug repurposing. Repurposing has generally been guided through clinical experience and small trials. At this time, none of the drug candidates have been approved for use, which may be due, in part, to the lack of pharmacokinetic/pharmacodynamic information on the repurposed medications in the target patient population. Greater consideration for the disease pathophysiology, drug pharmacology and potential drug-target interactions, specifically at the site of action, would improve drug repurposing and facilitate drug development. Incorporating advanced translational and clinical pharmacological approaches in preclinical studies and early-stage clinical trials will improve the success of repurposed drugs for X-ALD as well as other rare diseases.

Antioxidants resveratrol and SkQ1 attenuate praziquantel adverse effects on the liver in Opisthorchis felineus infected hamsters

Anthelmintic praziquantel (PZQ) is the drug of the choice for opisthorchiasis, schistosomiasis and other trematodiases therapy for several decades. Despite its good therapeutic performance and effective control of trematode infections, PZQ has some shortcomings; its inability to counteract disease sequelae necessitates novel therapeutic strategies. Testing of antioxidants that have proven themselves in clinical practice, in combination with this anthelmintic drug, offers new opportunities for developing alternatives to PZQ monotherapy. The effects of two antioxidants combined with PZQ on histological parameters of liver tissue were evaluated in a hamster model of opisthorchiasis felinea. Liver pathology including the parenchyma state, accumulation of neutral lipids and 4-Hydroxy-2-nonenal as a lipid peroxidation product, biochemical characteristics of hamster blood serum, and mRNA expression of inflammation- and fibrogenesis-associated genes were determined. PZQ and opisthorchiasis caused liver accumulation of lipids and glycogen. The combination of PZQ with resveratrol (RSV) or 10-(6'-plastoquinonyl)decyltriphenylphosphonium (SkQ1) significantly reduced hepatocyte changes (P = 0.009 and P = 0.009, respectively, Mann-Whitney U test) as compared with infected hamsters treated only with PZQ. RSV and SkQ1 significantly reduced cholangiocyte hyperplasia, bile duct proliferation, fibrosis, and lipid droplet and glycogen granule accumulation. The downregulation of 4-hydroxynonenal was also observed. The combinations of the anthelmintic drug with antioxidants RSV and SkQ1 ameliorate host oxidative stress and mitigate adverse effects of PZQ on hepatic parenchyma. The use of drug combinations may improve the action of standard anthelmintic agents, such as PZQ, which still remains the most effective agent against adult trematodes.

Modulation of mitochondrial and inflammatory homeostasis through RIP140 is neuroprotective in an adrenoleukodystrophy mouse model

AIMS

Mitochondrial dysfunction and inflammation are at the core of axonal degeneration in several multifactorial neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease, and Parkinson's disease. The transcriptional coregulator RIP140/NRIP1 (receptor-interacting protein 140) modulates these functions in liver and adipose tissue, but its role in the nervous system remains unexplored. Here, we investigated the impact of RIP140 in the Abcd1^- mouse model of X-linked adrenoleukodystrophy (X-ALD), a genetic model of chronic axonopathy involving the convergence of redox imbalance, bioenergetic failure, and chronic inflammation.

METHODS AND RESULTS

We provide evidence that RIP140 is modulated through a redox-dependent mechanism driven by very long-chain fatty acids (VLCFAs), the levels of which are increased in X-ALD. Genetic inactivation of RIP140 prevented mitochondrial depletion and dysfunction, bioenergetic failure, inflammatory dysregulation, axonal degeneration and associated locomotor disabilities in vivo in X-ALD mouse models.

CONCLUSIONS

Together, these findings show that aberrant overactivation of RIP140 promotes neurodegeneration in X-ALD, underscoring its potential as a therapeutic target for X-ALD and other neurodegenerative disorders that present with metabolic and inflammatory dyshomeostasis.

Concurrent axon and myelin destruction differentiates X-linked adrenoleukodystrophy from multiple sclerosis

Cerebral disease manifestation occurs in about two thirds of males with X-linked adrenoleukodystrophy (CALD) and is fatally progressive if left untreated. Early histopathologic studies categorized CALD as an inflammatory demyelinating disease, which led to repeated comparisons to multiple sclerosis (MS). The aim of this study was to revisit the relationship between axonal damage and myelin loss in CALD. We applied novel immunohistochemical tools to investigate axonal damage, myelin loss and myelin repair in autopsy brain tissue of eight CALD and 25 MS patients. We found extensive and severe acute axonal damage in CALD already in prelesional areas defined by microglia loss and relative myelin preservation. In contrast to MS, we did not observe selective phagocytosis of myelin, but a concomitant decay of the entire axon-myelin unit in all CALD lesion stages. Using a novel marker protein for actively remyelinating oligodendrocytes, breast carcinoma-amplified sequence (BCAS) 1, we show that repair pathways are activated in oligodendrocytes in CALD. Regenerating cells, however, were affected by the ongoing disease process. We provide evidence that-in contrast to MS-selective myelin phagocytosis is not characteristic of CALD. On the contrary, our data indicate that acute axonal injury and permanent axonal loss are thus far underestimated features of the disease that must come into focus in our search for biomarkers and novel therapeutic approaches.

How the brain fights fatty acids' toxicity

Neurons spurn hydrogen-rich fatty acids for energizing oxidative ATP synthesis, contrary to other cells. This feature has been mainly attributed to a lower yield of ATP per reduced oxygen, as compared to glucose. Moreover, the use of fatty acids as hydrogen donor is accompanied by severe β-oxidation-associated ROS generation. Neurons are especially susceptible to detrimental activities of ROS due to their poor antioxidative equipment. It is also important to note that free fatty acids (FFA) initiate multiple harmful activities inside the cells, particularly on phosphorylating mitochondria. Several processes enhance FFA-linked lipotoxicity in the cerebral tissue. Thus, an uptake of FFA from the circulation into the brain tissue takes place during an imbalance between energy intake and energy expenditure in the body, a situation similar to that during metabolic syndrome and fat-rich diet. Traumatic or hypoxic brain injuries increase hydrolytic degradation of membrane phospholipids and, thereby elevate the level of FFA in neural cells. Accumulation of FFA in brain tissue is markedly associated with some inherited neurological disorders, such as Refsum disease or X-linked adrenoleukodystrophy (X-ALD). What are strategies protecting neurons against FFA-linked lipotoxicity? Firstly, spurning the β-oxidation pathway in mitochondria of neurons. Secondly, based on a tight metabolic communication between neurons and astrocytes, astrocytes donate metabolites to neurons for synthesis of antioxidants. Further, neuronal autophagy of ROS-emitting mitochondria combined with the transfer of degradation-committed FFA for their disposal in astrocytes, is a potent protective strategy against ROS and harmful activities of FFA. Finally, estrogens and neurosteroids are protective as triggers of ERK and PKB signaling pathways, consequently initiating the expression of various neuronal survival genes via the formation of cAMP response element-binding protein (CREB).

mTOR inhibition improves mitochondria function/biogenesis and delays cardiovascular aging in kidney transplant recipients with chronic graft dysfunction

CVD remains the major cause of mortality with graft functioning in Kidney transplant recipients (KTRs), with an estimated risk of CV events about 50-fold higher than in the general population. Many strategies have been considered to reduce the CV risk such as the use of mTOR inhibitors. We evaluate whether chronic mTOR inhibition might influence CV aging in KTRs studying the molecular mechanisms involved in this effect. We retrospectively analyzed 210 KTRs with stable graft function on therapy with CNI and mycophenolic acid (Group A, 105 pts.), or with CNI and mTORi (Everolimus, Group B, 105 pts.). The presence of mTOR inhibitor in immunosuppressive therapy was associated to increase serum levels of Klotho with concomitant reduction in FGF-23, with a significant decrease in left ventricular mass. In addition, KTRs with mTORi improved mitochondrial function/biogenesis in PBMC with more efficient oxidative phosphorylation, antioxidant capacity and glutathione peroxidase activity. Finally, group B KTRs presented reduced levels of inflammaging markers such as reduced serum pentraxin-3 and p21ink expression in PBMC. In conclusion, we demonstrated that mTOR inhibition in immunosuppressive protocols prevents the occurrence and signs of CV aging in KTRs.

Autophagy in white matter disorders of the CNS: mechanisms and therapeutic opportunities

Autophagy is a constitutive process that degrades, recycles and clears damaged proteins or organelles, yet, despite activation of this pathway, abnormal proteins accumulate in neurons in neurodegenerative diseases and in oligodendrocytes in white matter disorders. Here, we discuss the role of autophagy in white matter disorders, including neurotropic infections, inflammatory diseases such as multiple sclerosis, and in hereditary metabolic disorders and acquired toxic‐metabolic disorders. Once triggered due to cell stress, autophagy can enhance cell survival or cell death that may contribute to oligodendrocyte damage and myelin loss in white matter diseases. For some disorders, the mechanisms leading to myelin loss are clear, whereas the aetiological agent and pathological mechanisms are unknown for other myelin disorders, although emerging studies indicate that a common mechanism underlying these disorders is dysregulation of autophagic pathways. In this review we discuss the alterations in the autophagic process in white matter disorders and the potential use of autophagy‐modulating agents as therapeutic approaches in these pathological conditions. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

The Value of Mouse Models of Rare Diseases: A Spanish Experience

Animal models are invaluable for biomedical research, especially in the context of rare diseases, which have a very low prevalence and are often complex. Concretely mouse models provide key information on rare disease mechanisms and therapeutic strategies that cannot be obtained by using only alternative methods, and greatly contribute to accelerate the development of new therapeutic options for rare diseases. Despite this, the use of experimental animals remains controversial. The combination of respectful management, ethical laws and transparency regarding animal experimentation contributes to improve society’s opinion about biomedical research and positively impacts on research quality, which eventually also benefits patients. Here we present examples of current advances in preclinical research in rare diseases using mouse models, together with our perspective on future directions and challenges.

High-dose biotin restores redox balance, energy and lipid homeostasis, and axonal health in a model of adrenoleukodystrophy

Biotin is an essential cofactor for carboxylases that regulates the energy metabolism. Recently, high-dose pharmaceutical-grade biotin (MD1003) was shown to improve clinical parameters in a subset of patients with chronic progressive multiple sclerosis. To gain insight into the mechanisms of action, we investigated the efficacy of high-dose biotin in a genetic model of chronic axonopathy caused by oxidative damage and bioenergetic failure, the Abcd1^- mouse model of adrenomyeloneuropathy. High-dose biotin restored redox homeostasis driven by NRF-2, mitochondria biogenesis and ATP levels, and reversed axonal demise and locomotor impairment. Moreover, we uncovered a concerted dysregulation of the transcriptional program for lipid synthesis and degradation in the spinal cord likely driven by aberrant SREBP-1c/mTORC1signaling. This resulted in increased triglyceride levels and lipid droplets in motor neurons. High-dose biotin normalized the hyperactivation of mTORC1, thus restoring lipid homeostasis. These results shed light into the mechanism of action of high-dose biotin of relevance for neurodegenerative and metabolic disorders.

Bone marrow deficiency of mRNA decaying protein Tristetraprolin increases inflammation and mitochondrial ROS but reduces hepatic lipoprotein production in LDLR knockout mice

Tristetraprolin (TTP), an mRNA binding and decaying protein, plays a significant role in controlling inflammation by decaying mRNAs encoding inflammatory cytokines such as TNFalpha. We aimed to test a hypothesis that TTP in bone marrow (BM) cells regulates atherogenesis by modulating inflammation and lipid metabolism through the modulation of oxidative stress pathways by TTP target genes. In a BM transplantation study, lethally irradiated atherogenic LDLR^-/- mice were reconstituted with BM cells from either wild type (TTP^+/+) or TTP knockout (TTP^-/-) mice, and fed a Western diet for 12 weeks. We made the following observations: (1) TTP^-/- BM recipients display a significantly higher systemic and multi-organ inflammation than TTP^+/+ BM recipients; (2) BM TTP deficiency modulates hepatic expression of genes, detected by microarray, involved in lipid metabolism, inflammatory responses, and oxidative stress; (3) TTP^-/- BM derived macrophages increase production of mitochondrial reactive oxygen species (mtROS); (4) BM-TTP^-/- mice display a significant reduction in serum VLDL/LDL levels, and attenuated hepatic steatosis compared to controls; and (5) Reduction of serum VLDL/LDL levels offsets the increased inflammation, resulting in no changes in atherosclerosis. These findings provide a novel mechanistic insight into the roles of TTP-mediated mRNA decay in bone marrow-derived cells in regulating systemic inflammation, oxidative stress, and liver VLDL/LDL biogenesis.

The peroxisomal fatty acid transporter ABCD1/PMP-4 is required in the C. elegans hypodermis for axonal maintenance: A worm model for adrenoleukodystrophy

Adrenoleukodystrophy is a neurometabolic disorder caused by a defective peroxisomal ABCD1 transporter of very long-chain fatty acids (VLCFAs). Its pathogenesis is incompletely understood. Here we characterize a nematode model of X-ALD with loss of the pmp-4 gene, the worm orthologue of ABCD1. These mutants recapitulate the hallmarks of X-ALD: i) VLCFAs accumulation and impaired mitochondrial redox homeostasis and ii) axonal damage coupled to locomotor dysfunction. Furthermore, we identify a novel role for PMP-4 in modulating lipid droplet dynamics. Importantly, we show that the mitochondria targeted antioxidant MitoQ normalizes lipid droplets size, and prevents axonal degeneration and locomotor disability, highlighting its therapeutic potential. Moreover, PMP-4 acting solely in the hypodermis rescues axonal and locomotion abnormalities, suggesting a myelin-like role for the hypodermis in providing essential peroxisomal functions for the nematode nervous system.

Bergenin impedes the generation of extracellular matrix in glomerular mesangial cells and ameliorates diabetic nephropathy in mice by inhibiting oxidative stress via the mTOR/β-TrcP/Nrf2 pathway

Bergenin, a plant polyphenol, has been reported to lower the blood glucose level and ameliorate kidney function in streptozotocin (STZ)-induced diabetic rats. Herein, its protective effect on diabetic nephropathy (DN) was explored in view of extracellular matrix (ECM) generation in glomerular mesangial cells. Glomerular mesangial cells were treated with high glucose, and Q-PCR as well as western blot were used to determine the expression of ECM. To establish the participation and role of mammalian target of rapamycin (mTOR) and nuclear factor erythroid-derived 2-related factor 2 (Nrf2) in ECM generation, a combination of l-leucine (activator of mTOR) and Nrf2 shRNA transfection were performed, respectively. Moreover, a DN model was established in mice using high-glucose/high-fat diet and STZ. Bergenin impeded the generation of TGF-β1 and ECM, decreased the levels of intracellular superoxide anion and hydrogen peroxide, and increased the activity of antioxidant enzymes in the glomerular mesangial cells (HBZY-1 and HRMC cells) treated with high glucose. The inhibition of ECM generation by bergenin was dependent on the down-regulation of oxidative stress as confirmed via a superoxide overexpression system. The activation of Nrf2 was required for bergenin to inhibit the oxidative stress and ECM generation. Moreover, bergenin was found to inhibit the phosphorylation of mTOR, which is located at the upstream of Nrf2. Bergenin did not interfere with the expression of Nrf2 mRNA and Keap1 (the classic degradation control factor of Nrf2), but markedly inhibited the protein expression of the β-TrcP, an effect which could be abolished by l-leucine. In DN model mice, l-leucine diminished the ability of bergenin to reduce the levels of superoxide anion, hydrogen peroxide and ECM, which contributed to the eradication of the ameliorative effect of bergenin on nephropathy. Bergenin can inhibit glucose-induced ECM production in glomerular mesangial cells through the down-regulation of oxidative stress via the mTOR/β-TrcP/Nrf2 pathway, and it might be a candidate drug for the prevention and treatment of DN.

Inhibition of Opisthorchis felineus glutathione-dependent prostaglandin synthase by resveratrol correlates with attenuation of cholangiocyte neoplasia in a hamster model of opisthorchiasis

Food-borne trematodiases represent major neglected parasitic diseases. Trematodes of the family Opisthorchiidae including Opisthorchis felineus, Opisthorchis viverrini and Clonorchis sinensis are ranked eight on the global list of the 24 most prevalent food-borne parasites. Chronic O. felineus infection symptoms include precancerous lesions with the potential for malignancy. In recent decades, liver flukes of the family Opisthorchiidae have been extensively scientifically explored, however despite this the molecular mechanisms of O. felineus pathogenicity and its carcinogenic potential have not been studied. Opisthorchis felineus glutathione-dependent prostaglandin synthase (GST σ) is the major component of the excretory-secretory product of this liver fluke. We hypothesised that the activity of this enzyme is involved in the infection pathogenesis, including the formation of precancerous lesions. To test this hypothesis and to gain insights into the mechanisms of precancerous lesion formation, we (i) investigated whether excretory parasitic GST σ retains its enzymatic activity, (ii) tested resveratrol (RSV) as a possible inhibitor of this enzyme, and (iii) assessed biliary neoplasia and oxidative DNA damage as well as the expression of neoplasia and fibrogenesis marker genes after prolonged administration of RSV in a hamster model. RSV was found to inhibit GST σ enzymatic activity in a dose-dependent manner (R = 0.85, P < 0.001; half-maximal effective dose (ED₅₀) = 48.6 μM). Prolonged administration of RSV significantly suppressed high-grade biliary neoplasia (P = 0.008), attenuated upregulation of hyperplasia and fibrogenesis-related genes (Tgfb, α-SMA and CK7), and decreased the elevated oxidative DNA damage. Taking into account that RSV can influence a wide range of pathways, further research is needed to confirm the role of GST σ in O. felineus pathogenicity. Nevertheless, the chemopreventive effect of RSV targeting biliary neoplasia formation might be useful for improving the outcomes in infected populations and represents a compelling rationale for RSV testing in combination chemotherapy of opisthorchiasis.

Biopharmaceutical Monotargeting versus 'Universal Targeting' of Late-Onset Alzheimer's Disease Using Mixtures of Pleiotropic Natural Compounds

A five-year close reading of the scientific literature on late-onset Alzheimer’s disease (AD) has prompted the invention of a novel therapeutic method that biomechanistically targets the targetable disease-process targets of AD with one or another mixture of non-toxic pleiotropic natural compounds. The featured mixture herein is comprised of curcumin, resveratrol, and EGCG. The mixture’s targets include central pathological elements of AD (including amyloid, tau, synaptic dysfunction, oxidative stress, mitochondrial dysfunction, and aberrant neuroinflammation), modifiable risk factors, comorbidities, and epigenetic elements. The featured mixture and other such mixtures are suitable for long-term use, and may be applied to any stage of AD, including primary and secondary prevention. Such mixtures also would be amenable for use as pre-treatment, co-treatment, and post-treatment applications with certain biopharmaceutical agents. The targeting focus here is the major credible hypotheses of AD. The focus of future such articles will include other AD-related targets, modifiable risk factors and comorbidities, APOE4, epigenetic factors, bioavailability, dose response, and implications for clinical testing. The “universal targeting” method described herein—that is, “targeting the targetable targets” of AD using certain mixtures of natural compounds—is reprogrammable and thus is applicable to other chronic neurological conditions, including Parkinson’s disease, vascular dementia, ischemic-stroke prevention and recovery, and sports-related head injuries and sequelae leading to chronic traumatic encephalopathy.

mTOR and Aging: An Old Fashioned Dress

Aging is a physiologic/pathologic process characterized by a progressive impairment of cellular functions, supported by the alterations of several molecular pathways, leading to an increased cell susceptibility to injury. This deterioration is the primary risk factor for several major human pathologies. Numerous cellular processes, including genomic instability, telomere erosion, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, stem cell exhaustion, and altered intercellular signal transduction represent common denominators of aging in different organisms. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved nutrient sensing protein kinase that regulates growth and metabolism in all eukaryotic cells. Studies in flies, worms, yeast, and mice support the hypothesis that the mTOR signalling network plays a pivotal role in modulating aging. mTOR is emerging as the most robust mediator of the protective effects of various forms of dietary restriction, which has been shown to extend lifespan and slow the onset of age-related diseases across species. Herein we discuss the role of mTor signalling network in the development of classic age-related diseases, focused on cardiovascular system, immune response, and cancer.

Aberrant regulation of the GSK-3β/NRF2 axis unveils a novel therapy for adrenoleukodystrophy

The nuclear factor erythroid 2‐like 2 (NRF2) is the master regulator of endogenous antioxidant responses. Oxidative damage is a shared and early‐appearing feature in X‐linked adrenoleukodystrophy (X‐ALD) patients and the mouse model (Abcd1 null mouse). This rare neurometabolic disease is caused by the loss of function of the peroxisomal transporter ABCD1, leading to an accumulation of very long‐chain fatty acids and the induction of reactive oxygen species of mitochondrial origin. Here, we identify an impaired NRF2 response caused by aberrant activity of GSK‐3β. We find that GSK‐3β inhibitors can significantly reactivate the blunted NRF2 response in patients’ fibroblasts. In the mouse models (Abcd1⁻ and Abcd1⁻/Abcd2^−/− mice), oral administration of dimethyl fumarate (DMF/BG12/Tecfidera), an NRF2 activator in use for multiple sclerosis, normalized (i) mitochondrial depletion, (ii) bioenergetic failure, (iii) oxidative damage, and (iv) inflammation, highlighting an intricate cross‐talk governing energetic and redox homeostasis in X‐ALD. Importantly, DMF halted axonal degeneration and locomotor disability suggesting that therapies activating NRF2 hold therapeutic potential for X‐ALD and other axonopathies with impaired GSK‐3β/NRF2 axis.

Diagnosis of 'possible' mitochondrial disease: an existential crisis

Primary genetic mitochondrial diseases are often difficult to diagnose, and the term 'possible' mitochondrial disease is used frequently by clinicians when such a diagnosis is suspected. There are now many known phenocopies of mitochondrial disease. Advances in genomic testing have shown that some patients with a clinical phenotype and biochemical abnormalities suggesting mitochondrial disease may have other genetic disorders. In instances when a genetic diagnosis cannot be confirmed, a diagnosis of 'possible' mitochondrial disease may result in harm to patients and their families, creating anxiety, delaying appropriate diagnosis and leading to inappropriate management or care. A categorisation of 'diagnosis uncertain', together with a specific description of the metabolic or genetic abnormalities identified, is preferred when a mitochondrial disease cannot be genetically confirmed.

The Autophagy-Lysosomal Pathways and Their Emerging Roles in Modulating Proteostasis in Tumors

In normal physiological condition, the maintenance of cellular proteostasis is a prerequisite for cell growth, functioning, adapting to changing micro-environments, and responding to extracellular stress. Cellular proteostasis is maintained by specific proteostasis networks (PNs) to prevent protein misfolding, aggregating, and accumulating in subcellular compartments. Commonly, the PNs are composed of protein synthesis, molecular chaperones, endoplasmic reticulum (ER), unfolded protein response (UPR), stress response pathways (SRPs), secretions, ubiquitin proteasome system (UPS), and autophagy-lysosomal pathways (ALPs). Although great efforts have been made to explore the underlying detailed mechanisms of proteostasis, there are many questions remain to explore, especially in proteostasis regulated by the ALPs. Proteostasis out-off-balance is correlated with various human diseases such as diabetes, stroke, inflammation, hypertension, pulmonary fibrosis, and Alzheimer’s disease. Enhanced regulation of PNs is observed in tumors, thereby indicating that proteostasis may play a pivotal role in tumorigenesis and cancer development. Recently, inhibitors targeting the UPS have shown to be failed in solid tumor treatment. However, there is growing evidence showing that the ALPs play important roles in regulation of proteostasis alone or with a crosstalk with other PNs in tumors. In this review, we provide insights into the proteostatic process and how it is regulated by the ALPs, such as macroautophagy, aggrephagy, chaperone-mediated autophagy, microautophagy, as well as mitophagy during tumor development.

Natural history of a cohort of ABCD1 variant female carriers

BACKGROUND AND PURPOSE

The therapeutic scenario of X-linked adrenoleukodystrophy (X-ALD) is rapidly changing. Whereas the disease is well characterized in men, the condition remains to be fully clarified in women carrying ATP binding cassette subfamily D member 1 (ABCD1) variants. Specifically, data on clinical progression are needed, in order to recommend any appropriate management. The objective of this study was to outline the natural history of a cohort of untreated ABCD1 heterozygous female carriers.

METHODS

Longitudinal data from a single-center population of 60 carriers were retrospectively reviewed. Demographics, anthropometrics, serum very long chain fatty acid (VLCFA) levels, clinical parameters and the Adult ALD Clinical Score (AACS) were collected from every recorded visit in a 7-year period and analyzed to define the phenotype modifications, to determine factors associated with clinical features, and to estimate the annual progression rate and the subsequent sample size for interventional trials.

RESULTS

Thirty-two patients were eligible for the study, and 59.4% were symptomatic at baseline. Clinical severity worsens with age which increases risk of symptom onset, the cut-off of 41 years being crucial for phenoconversion. VLCFA levels were not predictive and did not change over time. Symptomatic carriers were followed up for 3.45 ± 2.1 years. The AACS increased at an annual rate of 0.24 points. The estimated sample size for 30% reduction in annual progression at 80% power was 272.

CONCLUSIONS

This study provides data on the natural disease progression of untreated ABCD1 heterozygous female carriers, demonstrating the relevance of aging. The estimated annual increase of the AACS will be useful for future interventional studies.

Oxidative Imbalance, Nitrative Stress, and Inflammation in C6 Glial Cells Exposed to Hexacosanoic Acid: Protective Effect of N-acetyl-L-cysteine, Trolox, and Rosuvastatin

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurometabolic disorder caused by disfunction of the ABCD1 gene, which encodes a peroxisomal protein responsible for the transport of the very long-chain fatty acids from the cytosol into the peroxisome, to undergo β-oxidation. The mainly accumulated saturated fatty acids are hexacosanoic acid (C26:0) and tetracosanoic acid (C24:0) in tissues and body fluids. This peroxisomal disorder occurs in at least 1 out of 20,000 births. Considering that pathophysiology of this disease is not well characterized yet, and glial cells are widely used in studies of protective mechanisms against neuronal oxidative stress, we investigated oxidative damages and inflammatory effects of vesicles containing lecithin and C26:0, as well as the protection conferred by N-acetyl-L-cysteine (NAC), trolox (TRO), and rosuvastatin (RSV) was assessed. It was verified that glial cells exposed to C26:0 presented oxidative DNA damage (measured by comet assay and endonuclease III repair enzyme), enzymatic oxidative imbalance (high catalase activity), nitrative stress [increased nitric oxide (NO) levels], inflammation [high Interleukin-1beta (IL-1β) levels], and induced lipid peroxidation (increased isoprostane levels) compared to native glial cells without C26:0 exposure. Furthermore, NAC, TRO, and RSV were capable to mitigate some damages caused by the C26:0 in glial cells. The present work yields experimental evidence that inflammation, oxidative, and nitrative stress may be induced by hexacosanoic acid, the main accumulated metabolite in X-ALD, and that antioxidants might be considered as an adjuvant therapy for this severe neurometabolic disease.

Epigenomic signature of adrenoleukodystrophy predicts compromised oligodendrocyte differentiation

Epigenomic changes may either cause disease or modulate its expressivity, adding a layer of complexity to mendelian diseases. X‐linked adrenoleukodystrophy (X‐ALD) is a rare neurometabolic condition exhibiting discordant phenotypes, ranging from a childhood cerebral inflammatory demyelination (cALD) to an adult‐onset mild axonopathy in spinal cords (AMN). The AMN form may occur with superimposed inflammatory brain demyelination (cAMN). All patients harbor loss of function mutations in the ABCD1 peroxisomal transporter of very‐long chain fatty acids. The factors that account for the lack of genotype‐phenotype correlation, even within the same family, remain largely unknown. To gain insight into this matter, here we compared the genome‐wide DNA methylation profiles of morphologically intact frontal white matter areas of children affected by cALD with adult cAMN patients, including male controls in the same age group. We identified a common methylomic signature between the two phenotypes, comprising (i) hypermethylation of genes harboring the H3K27me3 mark at promoter regions, (ii) hypermethylation of genes with major roles in oligodendrocyte differentiation such as MBP, CNP, MOG and PLP1 and (iii) hypomethylation of immune‐associated genes such as IFITM1 and CD59. Moreover, we found increased hypermethylation in CpGs of genes involved in oligodendrocyte differentiation, and also in genes with H3K27me3 marks in their promoter regions in cALD compared with cAMN, correlating with transcriptional and translational changes. Further, using a penalized logistic regression model, we identified the combined methylation levels of SPG20, UNC45A and COL9A3 and also, the combined expression levels of ID4 and MYRF to be good markers capable of discriminating childhood from adult inflammatory phenotypes. We thus propose the hypothesis that an epigenetically controlled, altered transcriptional program may drive an impaired oligodendrocyte differentiation and aberrant immune activation in X‐ALD patients. These results shed light into disease pathomechanisms and uncover putative biomarkers of interest for prognosis and phenotypic stratification.

Modeling and rescue of defective blood-brain barrier function of induced brain microvascular endothelial cells from childhood cerebral adrenoleukodystrophy patients

Background

X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene. 40% of X-ALD patients will convert to the deadly childhood cerebral form (ccALD) characterized by increased permeability of the brain endothelium that constitutes the blood–brain barrier (BBB). Mutation information and molecular markers investigated to date are not predictive of conversion. Prior reports have focused on toxic metabolic byproducts and reactive oxygen species as instigators of cerebral inflammation and subsequent immune cell invasion leading to BBB breakdown. This study focuses on the BBB itself and evaluates differences in brain endothelium integrity using cells from ccALD patients and wild-type (WT) controls.

Methods

The blood–brain barrier of ccALD patients and WT controls was modeled using directed differentiation of induced pluripotent stem cells (iPSCs) into induced brain microvascular endothelial cells (iBMECs). Immunocytochemistry and PCR confirmed characteristic expression of brain microvascular endothelial cell (BMEC) markers. Barrier properties of iBMECs were measured via trans-endothelial electrical resistance (TEER), sodium fluorescein permeability, and frayed junction analysis. Electron microscopy and RNA-seq were used to further characterize disease-specific differences. Oil-Red-O staining was used to quantify differences in lipid accumulation. To evaluate whether treatment with block copolymers of poly(ethylene oxide) and poly(propylene oxide) (PEO–PPO) could mitigate defective properties, ccALD-iBMECs were treated with PEO–PPO block copolymers and their barrier properties and lipid accumulation levels were quantified.

Results

iBMECs from patients with ccALD had significantly decreased TEER (2592 ± 110 Ω cm²) compared to WT controls (5001 ± 172 Ω cm²). They also accumulated lipid droplets to a greater extent than WT-iBMECs. Upon treatment with a PEO–PPO diblock copolymer during the differentiation process, an increase in TEER and a reduction in lipid accumulation were observed for the polymer treated ccALD-iBMECs compared to untreated controls.

Conclusions

The finding that BBB integrity is decreased in ccALD and can be rescued with block copolymers opens the door for the discovery of BBB-specific molecular markers that can indicate the onset of ccALD and has therapeutic implications for preventing the conversion to ccALD.

Electronic supplementary material

The online version of this article (10.1186/s12987-018-0094-5) contains supplementary material, which is available to authorized users.

Loss of SIRT2 leads to axonal degeneration and locomotor disability associated with redox and energy imbalance

Sirtuin 2 (SIRT2) is a member of a family of NAD⁺‐dependent histone deacetylases (HDAC) that play diverse roles in cellular metabolism and especially for aging process. SIRT2 is located in the nucleus, cytoplasm, and mitochondria, is highly expressed in the central nervous system (CNS), and has been reported to regulate a variety of processes including oxidative stress, genome integrity, and myelination. However, little is known about the role of SIRT2 in the nervous system specifically during aging. Here, we show that middle‐aged, 13‐month‐old mice lacking SIRT2 exhibit locomotor dysfunction due to axonal degeneration, which was not present in young SIRT2 mice. In addition, these Sirt2^−/− mice exhibit mitochondrial depletion resulting in energy failure, and redox dyshomeostasis. Our results provide a novel link between SIRT2 and physiological aging impacting the axonal compartment of the central nervous system, while supporting a major role for SIRT2 in orchestrating its metabolic regulation. This underscores the value of SIRT2 as a therapeutic target in the most prevalent neurodegenerative diseases that undergo with axonal degeneration associated with redox and energetic dyshomeostasis.

Antioxidant Capacity and Superoxide Dismutase Activity in Adrenoleukodystrophy

Importance

X-linked adrenoleukodystrophy (ALD) may switch phenotype to the fatal cerebral form (ie, cerebral ALD [cALD]), the cause of which is unknown. Determining differences in antioxidant capacity and superoxide dismutase (SOD) levels between phenotypes may allow for the generation of a clinical biomarker for predicting the onset of cALD, as well as initiating a more timely lifesaving therapy.

Objective

To identify variations in the levels of antioxidant capacity and SOD activity between ALD phenotypes in patients with cALD or adrenomyeloneuropathy (AMN), heterozygote female carriers, and healthy controls and, in addition, correlate antioxidant levels with clinical outcome scores to determine a possible predictive value.

Design, Setting, and Participants

Samples of monocytes and blood plasma were prospectively collected from healthy controls, heterozygote female carriers, and patients with AMN or cALD. We are counting each patient as 1 sample in our study. Because adrenoleukodystrophy is an X-linked disease, the affected group populations of cALD and AMN are all male. The heterozygote carriers are all female. The samples were assayed for total antioxidant capacity and SOD activity. The data were collected in an academic hospital setting. Eligibility criteria included patients who received a diagnosis of ALD and heterozygote female carriers, both of which groups were compared with age-matched controls. The prospective samples (n = 30) were collected between January 2015 to January 2016, and existing samples were collected from tissue storage banks at the Kennedy Krieger Institute (n = 30). The analyses were performed during the first 3 months of 2016.

Main Outcome and Measures

Commercially available total antioxidant capacity and SOD assays were performed on samples of monocytes and blood plasma and correlated with magnetic resonance imaging severity score.

Results

A reduction in antioxidant capacity was shown between the healthy controls (0.225 mmol trolox equivalent) and heterozygote carriers (0.181 mmol trolox equivalent), and significant reductions were seen between healthy controls and patients with AMN (0.102 mmol trolox equivalent; P < .01), as well as healthy controls and patients with cALD (0.042 mmol trolox equivalent; P < .01). Superoxide dismutase activity in human blood plasma mirrored these reductions between prospectively collected samples from healthy controls (2.66 units/mg protein) and samples from heterozygote female carriers (1.91 units/mg protein), patients with AMN (1.39 units/mg protein; P = .01), and patients with cALD (0.8 units/mg protein; P < .01). Further analysis of SOD activity in biobank samples showed significant reductions between patients with AMN (0.89 units/mg protein) and patients with cALD (0.18 units/mg protein) (P = .03). Plasma SOD levels from patients with cALD demonstrated an inverse correlation to brain magnetic resonance imaging severity score (R2 = 0.75, P < .002). Longitudinal plasma SOD samples from the same patients (n = 4) showed decreased activity prior to and at the time of cerebral diagnosis over a period of 13 to 42 months (mean period, 24 months).

Conclusions and Relevance

Plasma SOD may serve as a potential biomarker for cerebral disease in ALD following future prospective studies.

The Peroxisome-Mitochondria Connection: How and Why?

Over the past decades, peroxisomes have emerged as key regulators in overall cellular lipid and reactive oxygen species metabolism. In mammals, these organelles have also been recognized as important hubs in redox-, lipid-, inflammatory-, and innate immune-signaling networks. To exert these activities, peroxisomes must interact both functionally and physically with other cell organelles. This review provides a comprehensive look of what is currently known about the interconnectivity between peroxisomes and mitochondria within mammalian cells. We first outline how peroxisomal and mitochondrial abundance are controlled by common sets of cis- and trans-acting factors. Next, we discuss how peroxisomes and mitochondria may communicate with each other at the molecular level. In addition, we reflect on how these organelles cooperate in various metabolic and signaling pathways. Finally, we address why peroxisomes and mitochondria have to maintain a healthy relationship and why defects in one organelle may cause dysfunction in the other. Gaining a better insight into these issues is pivotal to understanding how these organelles function in their environment, both in health and disease.

Comparison of the effects of major fatty acids present in the Mediterranean diet (oleic acid, docosahexaenoic acid) and in hydrogenated oils (elaidic acid) on 7-ketocholesterol-induced oxiapoptophagy in microglial BV-2 cells

Increased levels of 7-ketocholesterol (7KC), which results mainly from cholesterol auto-oxidation, are often found in the plasma and/or cerebrospinal fluid of patients with neurodegenerative diseases and might contribute to activation of microglial cells involved in neurodegeneration. As major cellular dysfunctions are induced by 7KC, it is important to identify molecules able to impair its side effects. Since consumption of olive and argan oils, and fish is important in the Mediterranean diet, the aim of the study was to determine the ability of oleic acid (OA), a major compound of olive and argan oil, and docosahexaenoic acid (DHA) present in fatty fishes, such as sardines, to attenuate 7KC-induced cytotoxic effects. Since elaidic acid (EA), the trans isomer of OA, can be found in hydrogenated cooking oils and fried foods, its effects on 7KC-induced cytotoxicity were also determined. In murine microglial BV-2 cells, 7KC induces cell growth inhibition, mitochondrial dysfunctions, reactive oxygen species overproduction and lipid peroxidation, increased plasma membrane permeability and fluidity, nuclei condensation and/or fragmentation and caspase-3 activation, which are apoptotic characteristics, and an increased LC3-II/LC3-I ratio, which is a criterion of autophagy. 7KC is therefore a potent inducer of oxiapoptophagy (OXIdation+APOPTOsis+autoPHAGY) on BV-2 cells. OA and EA, but not DHA, also favor the accumulation of lipid droplets revealed with Masson's trichrome, Oil Red O, and Nile Red staining. The cytotoxicity of 7KC was strongly attenuated by OA and DHA. Protective effects were also observed with EA. However, 7KC-induced caspase-3 activation was less attenuated with EA. Different effects of OA and EA on autophagy were also observed. In addition, EA (but not OA) increased plasma membrane fluidity, and only OA (but not EA) was able to prevent the 7KC-induced increase in plasma membrane fluidity. Thus, in BV-2 microglial cells, the principal fatty acids of the Mediterranean diet (OA, DHA) were able to attenuate the major toxic effects of 7KC, thus reinforcing the interest of natural compounds present in the Mediterranean diet to prevent the development of neurodegenerative diseases.

Brain energy metabolism spurns fatty acids as fuel due to their inherent mitotoxicity and potential capacity to unleash neurodegeneration

The brain uses long-chain fatty acids (LCFAs) to a negligible extent as fuel for the mitochondrial energy generation, in contrast to other tissues that also demand high energy. Besides this generally accepted view, some studies using cultured neural cells or whole brain indicate a moderately active mitochondrial β-oxidation. Here, we corroborate the conclusion that brain mitochondria are unable to oxidize fatty acids. In contrast, the combustion of liver-derived ketone bodies by neural cells is long-known. Furthermore, new insights indicate the use of odd-numbered medium-chain fatty acids as valuable source for maintaining the level of intermediates of the citric acid cycle in brain mitochondria. Non-esterified LCFAs or their activated forms exert a large variety of harmful side-effects on mitochondria, such as enhancing the mitochondrial ROS generation in distinct steps of the β-oxidation and therefore potentially increasing oxidative stress. Hence, the question arises: Why do in brain energy metabolism mitochondria selectively spurn LCFAs as energy source? The most likely answer are the relatively higher content of peroxidation-sensitive polyunsaturated fatty acids and the low antioxidative defense in brain tissue. There are two remarkable peroxisomal defects, one relating to α-oxidation of phytanic acid and the other to uptake of very long-chain fatty acids (VLCFAs) which lead to pathologically high tissue levels of such fatty acids. Both, the accumulation of phytanic acid and that of VLCFAs give an enlightening insight into harmful activities of fatty acids on neural cells, which possibly explain why evolution has prevented brain mitochondria from the equipment with significant β-oxidation enzymatic capacity.

Differentially expressed miRNAs in sepsis-induced acute kidney injury target oxidative stress and mitochondrial dysfunction pathways

Objective

To identify specific miRNAs involved in sepsis-induced AKI and to explore their targeting pathways.

Methods

The expression profiles of miRNAs in serum from patients with sepsis-induced AKI (n = 6), sepsis-non AKI (n = 6), and healthy volunteers (n = 3) were investigated by microarray assay and validated by quantitative PCR (qPCR). The targets of the differentially expressed miRNAs were predicted by Target Scan, mirbase and Miranda. Then the significant functions and involvement in signaling pathways of gene ontology (GO) and KEGG pathways were analyzed. Furthermore, eight miRNAs were randomly selected out of the differentially expressed miRNAs for further testing by qPCR.

Results

qPCR analysis confirmed that the expressions levels of hsa-miR-23a-3p, hsa-miR-4456, hsa-miR-142-5p, hsa-miR-22-3p and hsa-miR-191-5p were significantly lower in patients with sepsis compared with the healthy volunteers, while hsa-miR-4270, hsa-miR-4321, hsa-miR-3165 were higher in the sepsis patients. Statistically, miR-4321; miR-4270 were significantly upregulated in the sepsis-induced AKI compared with sepsis-non AKI, while only miR-4321 significantly overexpressed in the sepsis groups compared with control groups. GO analysis showed that biological processes regulated by the predicted target genes included diverse terms. They were related to kidney development, regulation of nitrogen compound metabolic process, regulation of cellular metabolic process, cellular response to oxidative stress, mitochondrial outer membrane permeabilization, etc. Pathway analysis showed that several significant pathways of the predicted target genes related to oxidative stress. miR-4321 was involved in regulating AKT1, mTOR and NOX5 expression while miR-4270 was involved in regulating PPARGC1A, AKT3, NOX5, PIK3C3, WNT1 expression. Function and pathway analysis highlighted the possible involvement of miRNA-deregulated mRNAs in oxidative stress and mitochondrial dysfunction.

Conclusion

This study might help to improve understanding of the relationship between serum miRNAs and sepsis-induced AKI, and laid an important foundation for further identification of the potential mechanisms of sepsis-induced AKI and oxidative stress and mitochondrial dysfunction.

Insights for Oxidative Stress and mTOR Signaling in Myocardial Ischemia/Reperfusion Injury under Diabetes

Diabetes mellitus (DM) displays a high morbidity. The diabetic heart is susceptible to myocardial ischemia/reperfusion (MI/R) injury. Impaired activation of prosurvival pathways, endoplasmic reticulum (ER) stress, increased basal oxidative state, and decreased antioxidant defense and autophagy may render diabetic hearts more vulnerable to MI/R injury. Oxidative stress and mTOR signaling crucially regulate cardiometabolism, affecting MI/R injury under diabetes. Producing reactive oxygen species (ROS) and reactive nitrogen species (RNS), uncoupling nitric oxide synthase (NOS), and disturbing the mitochondrial quality control may be three major mechanisms of oxidative stress. mTOR signaling presents both cardioprotective and cardiotoxic effects on the diabetic heart, which interplays with oxidative stress directly or indirectly. Antihyperglycemic agent metformin and newly found free radicals scavengers, Sirt1 and CTRP9, may serve as promising pharmacological therapeutic targets. In this review, we will focus on the role of oxidative stress and mTOR signaling in the pathophysiology of MI/R injury in diabetes and discuss potential mechanisms and their interactions in an effort to provide some evidence for cardiometabolic targeted therapies for ischemic heart disease (IHD).

Tauroursodeoxycholic bile acid arrests axonal degeneration by inhibiting the unfolded protein response in X-linked adrenoleukodystrophy

The activation of the highly conserved unfolded protein response (UPR) is prominent in the pathogenesis of the most prevalent neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS), which are classically characterized by an accumulation of aggregated or misfolded proteins. This activation is orchestrated by three endoplasmic reticulum (ER) stress sensors: PERK, ATF6 and IRE1. These sensors transduce signals that induce the expression of the UPR gene programme. Here, we first identified an early activator of the UPR and investigated the role of a chronically activated UPR in the pathogenesis of X-linked adrenoleukodystrophy (X-ALD), a neurometabolic disorder that is caused by ABCD1 malfunction; ABCD1 transports very long-chain fatty acids (VLCFA) into peroxisomes. The disease manifests as inflammatory demyelination in the brain or and/or degeneration of corticospinal tracts, thereby resulting in spastic paraplegia, with the accumulation of intracellular VLCFA instead of protein aggregates. Using X-ALD mouse model (Abcd1⁻ and Abcd1⁻/Abcd2^−/− mice) and X-ALD patient’s fibroblasts and brain samples, we discovered an early engagement of the UPR. The response was characterized by the activation of the PERK and ATF6 pathways, but not the IRE1 pathway, showing a difference from the models of AD, PD or ALS. Inhibition of PERK leads to the disruption of homeostasis and increased apoptosis during ER stress induced in X-ALD fibroblasts. Redox imbalance appears to be the mechanism that initiates ER stress in X-ALD. Most importantly, we demonstrated that the bile acid tauroursodeoxycholate (TUDCA) abolishes UPR activation, which results in improvement of axonal degeneration and its associated locomotor impairment in Abcd1⁻/Abcd2^−/− mice. Altogether, our preclinical data provide evidence for establishing the UPR as a key drug target in the pathogenesis cascade. Our study also highlights the potential role of TUDCA as a treatment for X-ALD and other axonopathies in which similar molecular mediators are implicated.

Liujunzi Tang, a famous traditional Chinese medicine, ameliorates cigarette smoke-induced mouse model of COPD

ETHNOPHARMACOLOGICAL RELEVANCE

Liujunzi Tang is a traditional herbal medicine widely used in East Asia and clinically applied to treat Phlegm-Heat Syndrome. The purpose of the present study was to investigate the protective effects of Liujunzi Tang on cigarette smoke-induced (CS) mouse model of chronic obstructive pulmonary disease (COPD) and explore its potential molecular mechanism.

MATERIALS AND METHODS

The mice received 1h of cigarette smoke for 8 weeks. The serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 were determined by enzyme-linked immunosorbent assay (ELISA) kits. Superoxide dismutase (SOD) and malondialdehyde (MDA) were tested by biochemical methods. Histopathological alteration was observed by hematoxylin-eosin (H&E) staining. Additionally, the expressions of nuclear transcription factor-κB (NF-κBp65) and (inhibitor of NF-κB)IκB-α were determined by western blot and immunohistochemistry analysis.

RESULTS

Liujunzi Tang enhanced the activities of antioxidant enzymes and attenuated the levels of lipid oxidative production, meanwhile significantly inhibited the generations of inflammatory cytokines by inhibiting the phosphorylation of IκB-α and NF-κB.

CONCLUSION

Our findings indicated that Liujunzi Tang exhibited the protective effect on cigarette smoke-induced COPD mice by anti-inflammatory and anti-oxidative properties through the inhibition of NF-κB activation.

Protective Effects of α-Tocopherol, γ-Tocopherol and Oleic Acid, Three Compounds of Olive Oils, and No Effect of Trolox, on 7-Ketocholesterol-Induced Mitochondrial and Peroxisomal Dysfunction in Microglial BV-2 Cells

Lipid peroxidation products, such as 7-ketocholesterol (7KC), may be increased in the body fluids and tissues of patients with neurodegenerative diseases and trigger microglial dysfunction involved in neurodegeneration. It is therefore important to identify synthetic and natural molecules able to impair the toxic effects of 7KC. We determined the impact of 7KC on murine microglial BV-2 cells, especially its ability to trigger mitochondrial and peroxisomal dysfunction, and evaluated the protective effects of α- and γ-tocopherol, Trolox, and oleic acid (OA). Multiple complementary chemical assays, flow cytometric and biochemical methods were used to evaluate the antioxidant and cytoprotective properties of these molecules. According to various complementary assays to estimate antioxidant activity, only α-, and γ-tocopherol, and Trolox had antioxidant properties. However, only α-tocopherol, γ-tocopherol and OA were able to impair 7KC-induced loss of mitochondrial transmembrane potential, which is associated with increased permeability to propidium iodide, an indicator of cell death. In addition, α-and γ-tocopherol, and OA were able to prevent the decrease in Abcd3 protein levels, which allows the measurement of peroxisomal mass, and in mRNA levels of Abcd1 and Abcd2, which encode for two transporters involved in peroxisomal β-oxidation. Thus, 7KC-induced side effects are associated with mitochondrial and peroxisomal dysfunction which can be inversed by natural compounds, thus supporting the hypothesis that the composition of the diet can act on the function of organelles involved in neurodegenerative diseases.